Skip to main content

Full text of "Respiratory care : the official journal of the American Association for Respiratory Therapy"

See other formats 


DECEMBER  1  999 
VOLUME  44 
NUMBER    12 

ISSN  0020-1324-RECACP 


A  MONTHLY  SCIENCE  JOURNAL 
44TH  YEAR— ESTABLISHED  1956 


Call  for  Abstracts 

Open  Forum  2000 

Deadline  February  29, 2000 


ORIGINAL  CONTRIBUTIONS 


Automated  Rotational  Therapy  for  Prevention  of  Respiratory 
Complications  during  Mechanical  Ventilation 

Medical  and  Psychiatric  Predictors  of  Airway  Reactivity 

Improvement  in  Pulmonary  and  Exercise  Performance  in 
Obese  Patients  after  Weight  Loss 

Performance  of  the  MicroPlus  Portable  Spirometer  vs  the 
SensorMedics  Vmax22  Diagnostic  Spirometer 

In  Vitro  Testing  of  MDI  Spacers:  Measuring  Respirable  Dose 
Output  with  Actuation  In-  or  Out-of-Phase  with  Inhalation 


SPECIAL  ARTICLE 


Possible  Underestimation  of  Shunt  Fraction  in  the 
Hepatopulmonary  Syndrome 


ANNUAL  INDEXES 


^O  Kf  K\  -V^     (Si- 


-i    .  ^ 


1^< 


'V-K 


1-- .•*/WIK-;V.'i  l^"! 


'.  V: 


.jr^ 


I  LEADING  INSTITUTIONS 
AVE  RELIED  ON  THE  ACCURA 
^QF  ASTECH  INSTRUMENTS, 
FOR  YEARS  *A 


n^k  V 


T^ 


^iP 


Just  as  ancient  institutions  relied  on  the  Az^ 
calendar  for  vital  measurements  of  time,  today's 
leading  medical  institutions  rely  on  ASTECH  Peak 
Flow  Meters  for  vital  patient  measurements* 
Because  more  accurate  information  leads  to  more 
effective  therapy. 

Entrust  the  health  of  your  patients  to  the  peak 
flow  meter  trusted  by  some  of  the  leading  medical 
hospitals  for  pulmonary  medicine. 

The  ASTECH  Peak  Flow  Meter.  A  precision  instru- 
ment with  a  record  of  accuracy  and  reproducibility 
that  has  stood  the  test  of  time  in  the  most 
demanding  environments. 

Call  800-527-4278  today  for  really  accurate  infor- 
mation about  a  really  accurate  peak  flow  meter. 

ASTECH  ^  PEAK  FLOW  METER 


on  product  info  card 


ZENITH  JW^ 
AWABDWSIB 


€'1999  DEY.  Al!  rights  reserved, 
09-733-00   1/99 

'  Na'ional  Jewish  Medical  and  Research  Cemer  (ranked  #1  lor  puimonary  diseases  by  U.S.  Neivs  and  \Stirld  Rcpor;. 
July  1998)  and  other  though!  leaders  use  the  Astech  fcak  Fio«'  Meter  exclusively. 


1 


•11  • 


77/ 


Literary  Awards 


From  The  American  Respiratory 
Care  Foundation 


Allen  DeVilbiss 
Technology  Paper  Award 

Best  Ordinal  Paper 


Radiometer  Award 


I 


Paul  B  Blanch  RRT 

Mechanical  Ventilator  Malfunctions:  A  Descriptive  and 

Comparative  Study  of  6  Common  Ventilator  Brands 

[RespirCare  1999;44(10):1 183-1 192] 


Fujlyasu  Kakizaki  PT,  Masato  Shibuya  MD  PhD, 

Tsutomu  Yamazaki  PT  PhD,  Minehiko  Yamada  MD  PhD, 

Hajime  Suzuki  MD  PhD,  &  Ikuo  Homma  MD  PhD 

Preliminary  Report  on  the  Effects  of  Respiratory  Muscle  Stretch  Gymnastics 

on  Chest  Wall  Mobility  in  Patients  with  Chronic  Obstructive 

Pulmonary  Disease 

[RespirCare  1999;44(4):409-414] 

James  B  Fink  MS  RRT  &  Rajiv  Dhand  MD 

Awarded  for  their  series  of  feature  papers  exploring  aerosol 
therapy  in  medicine 

Bronchodilator  Therapy  in  Mechanically  Ventilated  Patients 
[RespirCare  1999;44{l):53-69] 

Dry  Powder  Inhalers 
[Respir  Care  1 999;44(8):940-95 1  ] 

Bronchodilator  Resuscitation  in  the  Emergency  Department — 

Part  1  of  2:  Device  Selection 

[Respir  Care  1 999;44(  1 1 ):  1 353- 1 374] 


Saturation  Recorded  During  Rubbing  Motion 

Masmo  SET  accurately  tracks  the  desaturation  and  resaturatii 

SNfeye  the  Oxiamart  product  misses  the  hypoxemic  event. 

This  study  was  performed  on  adult  I'olunteers. 

Data  courtesy  of  Dr.  Steven  Barker  Ph.D.,  M.D.,  Professor^nd  Chairrruin, 

Departmen^^f  Anesthesiology,  University  of  Arizona 


Masimo  SET 
Motion  Hand 


16 

Minutes 

N-3000  (OXISMART) 
Motion  Hand 


17.5 


Reference  (N-200) 
Non-Motion  Hand 


the  proof  is  in  the  performance 


mafeion    study 


SpOj  System 


OXISMART 

N-3000      N-200 


False  Alarms 


0% 


36%       30% 


True  Hypoxemias  Missed      0%         16%        1% 

Source:  Barker  SJ.  Shah  NK.  The  Effects  of  Motion  on  the  Performance  of  Pulse  Oximeters 
in  Volunteers,  >tnesr/les/otog>'1997;86(1):101-108. 


la\A/    perfusion    st:udy 

SpOj  System 


OXISMART 

N-3000      N-200 


Drop  Out  Rate 


0.8%     9.9%      17.8% 


True  Hypoxemias  Missed    0%       33.3%     33.3% 

Source:  Barker  SJ.  Novak  S,  Morgan  S.  The  Performance  of  Three  Pulse  Oximeters  During 
Low  Perfusion  in  Volunteers,  -Anesfhesiotogy  f  997;87(3A):A409. 


The  facts  about  Masimo  SET  pulse  oximetry: 

The  only  pulse  oximetry  technology  clinically 
proven  accurate  during  motion  and  low  perfusion 

Virtually  eliminates  false  alarms 

More  reliable  in  detecting  true  alarms 

Continuous  monitoring  (no  freezing) 

Over  the  past  two  years,  approximately  one-third  of  the 
world's  pulse  oximetry  suppliers  have  adopted  Masimo  SET 
as  their  pulse  oximetry  solution.  Now,  more  than  twenty 
patient  monitors  are  available  from  leading  patient 
monitoring  companies  with  Masimo  SET  pulse  oximetry. 


Prior  to  the  introduction  of  Masimo  SET,  conventional 
pulse  oximeters  could  only  be  relied  upon  for  accurate 
measurement  during  ideal  conditions.  Masimo  SET  reliably 
and  continuously  tracks  changes  in  saturation  and  pulse  rate, 
giving  you  accurate  monitoring  when  you  need  it  most,  even 
when  your  patients  are  moving  or  have  low  perfusion. 

Prove  it  to  yourself  —  take  Masimo  SET  pulse  oximetry 
to  your  toughest  patients  and  perform  a  confirming 
CO-Oximeter  ABG.  If  the  Masimo  SET  pulse  oximeter 
measurement  is  further  from  the  CO-Oximeter 
measurement  than  any  other  non-Masimo  SET  pulse 
oximeter,  we  will  reimburse  the  cost  of  your  test.* 


for  mors  information  on  IVIaaimo  SET  pulaa  oxime1:ry  or  to  schedule  a  free  trial  evaluation,  contact  us  by  phone  or  internet 


■B77-4-l\/IASIMO 

Circle  140  on  product  Info  card 


v\/v\/v\/.  masimo .  com 

Visit  Booth  1202  In  Las  Vegas 


$ 


l$[ 


Instruments  and  sensors  containing  Masimo  SET  technology  are  identified  with  the  Masimo  SET  logo. 
Look  for  the  Masimo  SET  designation  to  ensure  accurate  pulse  oximetry  when  needed  most. 

"■t  must  be  performed  on  a  calibrated  CO-Oximeter  with  four  or  more  wsvelen^ha  (e.g.,  IL  482  or  Radiometer  0SM3).  Certain  other  rules  and  restrictions  apply.  Contact  Masimo  for  more  details. 
<j99  Manimo  Corporation.  Maaimo,  SET  and  %  are  federally  registered  trademarks  of  Masimo  Corporation.   N-3000.  OXISMART  and  N-200  are  trademarks  of  Nellcor  Puritan  Bennett. 


DECEMBER  1999  /  VOLUME  44  /  NUMBER  12 


FOR  INFORMATION, 
CONTACT: 

AARC  Membership  or  Other  AARC 
Services 

American  Association  for 

Respiratory  Care 

11030  Abies  Ln 

Dallas  TX  75229-4593 

(972)  243-2272  •  Fax  (972)  484-2720 

http://www.aarc.org 

Therapist  Registration  or 
Technician  Certification 

National  Board  for  Respiratory 

Care 

8310Nieman  Rd 

LenexaKS  66214 

(913)  599-4200  •  Fax  (913)  541-0156 

http://www.nbrc.org 

Accreditation  of  Education 
Programs 

Committee  on  Accreditation  for 

Respiratory  Care 

1701  W  Euless  Blvd.  Suite  300 

Euless  TX  76040 

(817)  283-2835  •  Fax  (817)  354-8519 

http://www.coarc.com 

Grants,  Scholarships,  Community 
Projects 

American  Respiratory  Care 

Foundation 

11030  Abies  Ln 

Dallas  TX  75229-4593 

(972)  243-2272  •  Fax  (972)  484-2720 

Government  Affairs  — 

Cheryl  West  MHA  (703-548-8506) 

State  Government  Affairs  — 

Jill  Eicher  MPA  (703-548-8538) 
1225  King  St,  Second  Floor 
Alexandria  VA  22314 
Fax  (703)  548-8499 


RE/PIRATORy 
O^RE 


RESPIRATORY  CARE  (ISSN  0020-1324.  USPS  0489- 
190)  is  published  monthly  by  Daedalus  Enterprises  Inc,  at 
1 1030  Abies  Lane.  Dallas  TX  75229-4593.  for  the  Amer- 
ican Association  for  Respiratory  Care.  One  volume  is 
published  per  year  beginning  each  January.  Subscription 
rates  are  $75  per  year  in  the  US;  $90  in  all  other  countries 
(for  airmail,  add  $94). 

The  contents  of  the  Journal  are  indexed  in  Hospital  and 
Health  Administration  Index.  Cumulative  Index  to  Nurs- 
ing and  Allied  Health  Literature,  EMBASE/Exerpta  Med- 
ica,  and  RNdex  Library  Edition.  Abridged  versions  of 
Respiratory  Care  are  also  published  in  Italian. 
French,  and  Japanese,  with  permission  from  Daedalus  En- 
terprises Inc. 

Periodicals  postage  paid  at  Dallas  TX  and  at  additional 
mailing  offices.  POSTMASTER:  Send  address  changes  to 
RESPIRATORY  CARE,  Membership  Office,  Daedalus  En- 
terprises Inc,  1 1030  Abies  Lane,  Dallas  TX  75229-4593. 

Printed  in  the  United  States  of  America 
Copyright  ©  1999,  by  Daedalus  Enterprises  Inc. 


ORIGINAL  CONTRIBUTIONS 


Automated  Rotational  Therapy  for  the  Prevention  of  Respiratory 

Complications  during  Mechanical  Ventilation 

by  Neil  R  Maclntyre  and  Michael  Helms — Durham,  North  Carolina, 

Richard  Wunderink — Memphis  Tennessee,  Gregory  Schmidt — Chicago  Illinois, 

and  Steven  A  Sahn — Charleston,  South  Carolina 


Medical  and  Psychiatric  Predictors  of  Airway  Reactivity 
by  Karen  B  Schmaling,  Niloofar  Afari,  Scott  Barnhart, 
and  Dedra  S  Buchwald — Seattle,  Washington 

Improvement  in  Pulmonary  and  Exercise  Performance  in  Obese 

Patients  after  Weight  Loss 

by  Michael  J  Caretla — East  Lansing,  Michigan, 

Susan  Blonshine  and  C  Mohan  Cera — Lansing,  Michigan, 

Ved  V  Gossain  and  Brad  Ropp — East  Lansing,  Michigan 


Performance  Comparison  of  the  Hand-Held  MicroPlus  Portable 
Spirometer  and  the  SensorMedics  Vmax22  Diagnostic  Spirometer 

by  William  E  Caras,  Michael  G  Winter,  Thomas  Dillard, 
and  Tammy  Reasor — Tacoma,  Washington 

In  Vitro  Testing  of  MDI  Spacers:  A  Technique  for  Measuring  Respirable 
Dose  Output  with  Actuation  In-Phase  or  Out-of-Phase  with  Inhalation 
by  Scott  A  Foss  and  Jean  W  Keppel — Tuscon,  Arizona 


1447 
1452 


1458 

1465 
1474 


SPECIAL  ARTICLE 


Possible  Underestimation  of  Shunt  Fraction  in  the  Hepatopulmonary  Syndrome  ^  .  -  - 
by  Kevin  McCarthy  and  James  K  Stoller — Cleveland,  Ohio  1  4  0  0 


PPT  NUGGETS 


A  66- Year-Old  Woman  with  Longstanding  Dyspnea  on  Exertion 
by  Niranjan  Seshadri  and  Atul  C  Mehta — Cleveland,  Ohio 

A  71-Year-Old  Man  with  Progressive  Shortness  of  Breath  and  Orthopnea 

by  Loutfi  S  Aboussouan — Detroit,  Michigan 


1489 
1491 


LETTERS 


Vital  Capacity  Maneuver  in  Modified  Spirometry  Technique 

by  Brenton  Eckert — Brisbane,  Australia 

Response  by  James  K  Stoller,  Daniel  Laskowski,  and  Kevin  McCarthy — Cleveland,  Ohio 


BOOKS,  FILMS,  TAPES,  &  SOFTWARE 

Interpretation  of  Pulmonary  Function  Tests:  A  Practical  Guide 

reviewed  bv  J  M  Cairo — New  Orleans,  Louisiana 


The  Handbook  of  Critical  Care  Drug  Therapy,  2nd  Edition 

reviewed  by  Richard  J  Maunder  and  Keith  Hyde — Portland,  Oregon 


1493 

1494 
1494 


Want  to  get  out  of  the  parts  business? 

Introducing  Praxair's  Grab  'n  Go.  The  all-in-one  portable  medical  oxygen  system. 


Praxair's  Grab  'n  Go™  system  is  an  oxygen  cylinder  with  a 
regulator  and  a  contents  gauge  already  attached.  It's  the 
fastest,  easiest,  safest  way  to  dispense  portable 
oxygen.  Here's  what  you  do:  Grab.  And  go. 

Because  the  Grab  'n  Go  system  has  no  sepa- 
rate parts,  you  don't  waste  time  searching  for  and 
keeping  track  of  equipment.  You  don't  waste 
money  maintaining  and  repairing  equipment. 
And  you  don't  hassle  with  wrenches  and  keys. 

With  Praxair's  Grab  'n  Go  system  you  have 
everything  you  need.  The  built-in  gauge  lets 
you  verify  contents  at  a  glance.  And  the  easy-to- 


PRAX  •  'M  (K-  M  (WrNG  AIRSTREiAM  design  and  GRAB  'N  GO  are  cither  uadernari^s  tn  rcgiMcird  Irjtlcmaits 
of  ftaxair  IV.Ini  liii'i.  Inc.  tnthc  Uiiilcd  Stales  and/or  nther  cotinlncs. 
0  1999.  pii- .  ■  U.  iinoL^y.  Ini'  All  ri|hls  reserved 
1099    P-»4;s 


use  regulator  lets  you  adjust  oxygen  flow  with  the  turn  of  a 
dial.  The  Grab'n  Go  system  also  has  a  handle  that  makes  it 
a  cinch  to  carry. 

Save  time.  End  frustration.  And  get  out  of  the 
parts  business. 

Want  to  try  Praxair's  Grab'n  Go  system?  Call 
1-800-299-7977  ext.  6961,  or  stop  by  our  web 
site  at  www.praxair.com/healthcare  to  find  out 
how  you  can  take  advantage  of  our  demo  pro- 
gram. And  while  you're  at  it,  check  out  Praxair's 
extensive  line  of  respiratory  gases,  equipment 
and  services. 


1PRAXAIR 


Making  our  planet  more  productive ' 

Circle  109  on  product  info  card 
Visit  Booth  629  in  Las  Vegas 


ALSO 
IN  THIS  ISSUE 

AARC  Membership 
1523                Application 

1416 

Abstracts  from 
Other  Journals 

1536 

Advertisers  Index 
&  Help  Lines 

1536 

Author 
Index 

1534 

Calendar 
of  Events 

1525 

Call  For  Open 
FORUM  Abstracts 

1499 

Correction  to  Open 
Forum  Abstracts 

1527 

Manuscript 
Preparation  Guide 

1531 

MedWatch 

1533 

New  Products 

1535 

Notices 

RE/PIRATORy 
CARE 

A  Monthly  Science  Journal 
Established  in  1956 

The  Official  Journal  of  the 

American  Association  for 

Respiratory  Care 


Rehabilitation  of  the  Patient  with  Respiratory  Disease 

reviewed  by  Martu  Cudjonsdottir  and  Claudia  F  Doitner — Veruno,  Italy 

SI  Units  for  Clinical  Measurement 

reviewed  by  Robert  L  Chatbiirn — Cleveland.  Ohio 

Publishing  Your  Medical  Research  Paper:  What  They  Don't 
Teach  in  Medical  School 

reviewed  by  David  J  Pierson — Seattle,  Washington 


CONTINUED... 

1495 
1496 

1496 


LITERARY  AWARDS 


1999  Award  Winners  and  Prizes 

1409 

ANNUAL    NDEXES  FOR  VOLUME  44, 

1999 

Appreciation  of  Reviewers:  Listing  of  This  Year's 
Manuscript  and  OPEN  FORUM  Reviewers 

1500 

Author  Index 

1502 

Subject  Index 

1509 

COMNG  N  JANUARYS  FEBRUARY  2000 

PROCEEDINGS  OF  THE 

STATE-OF-THE-ART 
JOURNAL  CONFERENCE 

ON 

LONG-TERM  OXYGEN 
THERAPY 


CO-CHAIRS: 
THOMAS  L  PETTY  MD 
DAVID  J  PIERSON  MD 


How  did  your  last  ventilator  setting 
affect  your  patient? 

Look  at  it  from  their  point  of  view 


Did  your  last  ventilator  change  improve  CO2 
elimination  or  make  it  worse?  Now  there  is  a  sys- 
tem that  tells  you  immediately  and  non-invasively. 

CO2SMO  Plus!  is  the  first  respiratory  profile  monitor 
to  provide  one  simple  method  to  measure  your 
patient's  response  to  ventilator  changes. 

COj  elimination,  alveolar  ventilation  and  deadspace 
are  parameters  that  provide  a  direct  correlation  to 
ventilatory  status  and  give  you  the  confidence  that 


your  ventilator  changes  are  optimized  for  your  patient. 
COjSMO  P/us.'  is  the  right  choice  for  ventilator 
management. 

For  more  information,  call  us  at  1-800-243-3444  or 
203-265-7701,  or  visit  us  at  www.novametrix.com. 


NOVAMETRIX 

MEDICAL  SYSTEMS  INC 

...simply,  the  leading  edge 

www.novametrix.com 


Circle  126  on  product  info  card 
Visit  Booth  1119  in  Las  Vegas 


EDITORIAL  OFFICE 

600  Ninth  Avenue,  Suite  702 

Seattle  WA  98104 

(206) 223-0558 

Fax (206) 223-0563 

www.rcjoumal.com 

MANAGING  EDITOR 

Ray  Masferrer  RRT 


ASSISTANT 
EDITOR 

Katherine  Kreilkamp 


EDITORIAL 
ASSISTANT 

Linda  Barcus 


COPY  EDITOR 

Matthew  Mere 

PRODUCTION 

Kelly  Piotrowski 

PUBLISHER 

Sam  P  Giordano  MBA  RRT 


MARKETING 

Dale  L  Griffiths 
Director  of  Marketing 

Tim  Goldsbury 
Director,  Advertising  Sales 

Beth  Binkley 

Advertising  Assistant 


EDITOR  IN  CHIEF 


RE/PIRATORy 

caRE 


A  Monthly  Science  Journal 
Established  in  1956 

The  Official  Journal  of  the 

American  Association  for 

Respiratory  Care 


David  J  Pierson  MD 

Harborview  Medical  Center 
University  of  Washington 
Seattle,  Washington 


ASSOCIATE  EDITORS 


Richard  D  Branson  RRT 
University  of  Cincinnati 
Cincinnati,  Ohio 


Charles  G  Durbin  Jr  MD 
University  of  Virginia 
Charlottesville,  Virginia 

EDITORIAL  BOARD 


Dean  R  Hess  PhD  RRT  FAARC 

Massachusetts  General  Hospital 
Harvard  University 
Boston,  Massachusetts 

James  K  Stoller  MD 

The  Cleveland  Clinic  Foundation 

Cleveland,  Ohio 


Thomas  A  Barnes  EdD  RRT 

Northeastern  University 
Boston,  Massachusetts 

Michael  J  Bishop  MD 

University  of  Washington 
Seattle,  Washington 

Bartoiome  R  Ceili  MD 

Tufts  University 
Boston,  Massachusetts 

Robert  L  Chatbum  RRT 
FAARC 

University  Hospitals  of  Cleveland 
Case  Western  Reserx'e  University 
Cleveland,  Ohio 

Luciano  Gattinoni  MD 

University  of  Milan 
Milan,  Italy 

John  E  Heffner  MD 

Medical  University  of  South  Carolina 
Charleston,  South  Carolina 

Mark  J  Heulitt  MD 

University  of  Arkansas 
Little  Rock.  ArkatLsas 


SECTION  EDITORS 


Leonard  D  Hudson  MD 

University  of  Washington 
Seattle,  Washington 

Robert  M  Kacmarek  PhD  RRT 

FAARC 

Massachusetts  General  Hospital 

Harvard  University 

Boston,  Massachusetts 

Toshihiko  Koga  MD 
Koga  Hospital 
Kurume.  Japan 

Marin  HKollefMD 

Washington  University 
St  Louis,  Missouri 

Patrick  Leger  MD 
Clinique  Medicate  Edouard  Rist 
Paris,  France 

Neil  R  Maclntyre  MD  FAARC 

Duke  University 
Durham,  North  Carolina 

John  J  Marini  MD 

University  of  Minnesota 
St  Paul,  Minnesota 


Shelley  C  Mishoe  PhD  RRT 
FAARC 

Medical  College  of  Georgia 
Augusta,  Georgia 

Joseph  L  Rau  PhD  RRT 
Georgia  State  University 
Atlanta,  Georgia 

Catherine  SH  Sassoon  MD 
University  of  California  Irvine 
Long  Beach,  California 

Arthur  S  Slutsky  MD 
University  of  Toronto 
Toronto,  Ontario,  Canada 

Martin  J  Tobin  MD 

Loyola  University 
Maywood,  Illinois 


STATISTICAL  CONSULTANT 

Gordon  D  Rubenfeld  MD 

University  of  Washington 
Seattle,  Washington 


Hugh  S  Mathewson  MD 
Joseph  L  Rau  PhD  RRT 
Drug  Capsule 


Charles  G  Irvin  PhD 

Gregg  L  Ruppel  MEd  RRT  RPFT  FAARC 

PFT  Comer 


Richard  D  Branson  RRT 
Robert  S  Campbell  RRT 
Kittredge's  Comer 


Jon  Nilsestuen  PhD  RRT  FAARC 
Ken  Hargett  RRT 
Graphics  Comer 


Patricia  Ann  Doorley  MS  RRT 
Charles  G  Durbin  Jr  MD 
Test  Your  Radiologic  Skill 


*•; 


Abstracts 


Summaries  of  Pertinent  Articles  in  Other  Journals 


Editorials,  Commentaries,  and  Reviews  to  Note 

NIPPV:  Patient- Ventilator  Synchrony:  The  Difference  Between  Success  and  Failure?  Kac- 
marek  RM.  Intensive  Care  Med  1999  Jul;25(7):645-647. 

The  Laryngeal  Mask  Airway:  Routine,  Risk,  or  Rescue?  Weiler  N,  Eberle  B,  Heinrichs  W. 
Intensive  Care  Med  1999  Jul;25(7):761-762. 

Intensive  Care  Medicine  Comes  of  Age — And  Offers  A  Multidisciplinary  Model  for  Future 
Emerging  Specialties  (editorial)— Soni  N.  Wyncoll  D.  BMJ  1999  Jul  31;319(7205):271-272. 

ABC  of  Intensive  Care:  Withdrawal  of  Treatment  (review)— Winter  B,  Cohen  S.  BMJ  1999 
Jul  31;319(7205):306-308. 

The  Ideal  Sedation  Assessment  Tool:  An  Elusive  Instrument  (editorial) — Wittbrodt  ET.  Crit 
Care  Med  1999  Jul;27(7):1384-1385. 

The  Esophageal  Detector  Device  Is  Unreliable  when  the  Stomach  Has  Been  Ventilated — 

Andres  AH,  Langenstein  H.  Anesthesiology  1999  Aug;91(2):.'i66-568. 

Airway  Exchange  Catheters:   Simple  Concept,  Potentially  Great  Danger  (editorial) — 
BenumofJL.  Anesthesiology  1999  Aug;91(2):342-344. 


Additional  Inspiratory  Work  of  Breathing 
Imposed  by  Tracheostomy  Tubes  and  Non- 
Ideal  Ventilator  Properties  in  Critically  III 

Patients— Haberthur  C,  Fabry  B.  Stocker  R, 
Ritz  R,  Guttmann  J.  Intensive  Care  Med  1999 

MayL25(5):514-5l9. 

OBJECTIVE:  To  determine  the  tracheostomy 
tube-related  additional  work  of  breathing 
(WOB.,jj)  in  critically  ill  patients  and  to  show 
its  reduction  by  different  ventilatory  modes.  DE- 
SIGN: Prospective,  clinical  study.  SETTING: 
Medical  ICU  of  a  university  teaching  hospital. 
INTERVENTION:  Standard  tracheostomy  due 
to  prolonged  respiratory  failure.  MEASURE- 
MENTS AND  RESULTS:  Ten  tracheos- 
tomized,  spontaneously  breathing  patients  were 
investigated.  As  the  tube  resistance  depends  on 
gas  flow,  patients  were  subdivided  according  to 
minute  ventilation  into  a  low  ventilation  group 
(=  10  L/niin;  n  =  5)  and  a  high  ventilation 
group  (>  10  Umin;  n  =  5).  The  WOB,,jj  due 
to  tube  resistance  and  non-ideal  ventilator  prop- 
erties was  calculated  on  the  basis  of  the  tracheal 
pressure  measured.  Ventilatory  modes  investi- 
gated were:  continuous  positive  airway  pres- 
sure (CPAP).  inspiratory  pressure  support  (IPS) 
of  5,  10.  and  15  cm  H,0  above  PEEP,  and 
automatic  lube  compensation  (ATC).  In  (he  low 
ventilation  group.  WOB.,,,,,  during  CPAP  was 
;»  382±0.1()6  J/L.  Il  was  reduced  to  below  15% 


of  that  value  by  ATC  or  IPS  more  than  5  cm 
HiO.  In  the  high  ventilation  group  WOB.,jj  dur- 
ing CPAP  increased  to  0.908 ±0.142  J/L.  In 
this  group,  however,  only  ATC  was  able  to  re- 
duce WOB,,jj  below  15%  of  the  value  observed 
in  the  CPAP  mode.  CONCLUSIONS:  The  re- 
sults indicate  that,  depending  on  respiratory  flow 
rate,  (I)  tracheostomy  tubes  can  cause  a  con- 
siderable amount  of  WOB,,jj.  and  (2)  ATC,  in 
contrast  to  IPS.  is  a  suitable  mode  to  compen- 
sate for  WOBadd  at  any  ventilatory  effort  of 
the  patient. 

Noninvasive  Ventilation:  Experience  at  a 
Community  Teaching  Hospital — Alsous  F. 
Amoateng-Adjepong  Y.  Manthous  CA.  Inten- 
sive Care  Med  1999  May;25(5):458-463. 

OBJECTIVE:  To  describe  our  hospital's  expe- 
rience with  noninvasive  positive  pressure  ven- 
tilation (bilevel  positive  airway  pressure;  Bi- 
PAP)  for  patients  with  respiratory  failure  (RF). 
DESIGN:  Retrospective,  observational  study. 
SETTING:  A  30()-bed  community  teaching  hos- 
pital. METHODS:  Medical  records  were  ana- 
lyzed for  physiologic  and  outcome  variables  for 
all  patients  who  received  BiPAP  for  RF  be- 
tween January  1994  and  December  1996.  RE- 
SULTS: Eighty  patients  with  a  mean  (±  S.E.) 
age  of  7 1.5 ±1.3  years  and  APACHE  II  score  of 
I7.2±0.6  received  BiPAP  for  RF  during  the 


study  period.  Thirty-one  patients  received  Bi- 
PAP for  hypoxemic  RF.  25  for  acute  hypercap- 
nic  RF.  9  for  chronic  hypercapnic  RF.  10  for 
postexlubation  RF  and  5  could  not  be  catego- 
rized. BiPAP  success  was  defined  as  no  need 
for  invasive  ventilation.  BiPAP  was  successful 
in  47  of  75  cases  that  could  be  classified;  all 
BiPAP  successes  lived  whereas  18  of  28  Bi- 
PAP failures  died.  In  the  overall  cohort.  BiPAP 
success  was  associated  with  a  lower  ICU  length 
of  stay  (5.8±0.9  versus  I0.6±1.4  days,  p  < 
0.01).  The  duration  of  BiPAP  dependency  in 
successful  ca.ses  was  35.3±6.7  h.  BiPAP  was 
successful  in  20  of  25  patients  with  acute  hy- 
percapnic RF  and  in  15  of  31  patients  with 
hypoxemic  RF.  The  risk  of  BiPAP  failure  was 
significantly  greater  (risk  ratio  =  2.6.  95%  CI  = 
1.1-6.1)  for  patients  with  hypoxemic  than  for 
those  with  hypercapnic  RF.  BiPAP  success  was 
marked  by  increased  PaoyF|„,  in  patients  with 
hypoxemic  RF  and  by  increased  pH  and  re- 
duced P(-„,  in  patients  with  hypercapnic  RF. 
BiPAP  use  was  also  successful  in  8  of  10  pa- 
tients who  developed  RF  within  48  h  of  endo- 
tracheal extubation.  CONCLUSIONS:  BiPAP 
is  highly  effective  in  selected  patients  with  RF 
during  routine  use  in  a  community  teaching  hos- 
pital. The  success  rate  is  higher  amongst  pa- 
tients presenting  with  hypercapnic  than  amongst 
those  with  hypoxemic  RF  and  BiPAP  failure  is 
associated  with  an  increa.sed  likelihood  of  in- 


1416 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Have  Ybu  "Hit"  The  Hub? 

The  Internet's  Fastest  Growing  Healthcare  Recruitment  Site 


For  Job  Seekers 

Thousands  of  Searchable  Jobs 
Hundreds  of  Hospital  Profiles 
Online  Healthcare  Magazine 
Career  Resource  Center 
Chat  Rooms  &  Discussion  Boards 


For  Facilities 

Broad  Healthcare  Exposure 
Customized  Facility  Profiles 
Over  4  Million  Hits  Per  Year 
Live  Online  Job  Postings 
Cost-Effective  Recruitment  Solutions 


An  entire  web  community  for 
Respiratory  Therapists  on  the  fast  tracic! 

www.hospitaJhiib.com 

Hub  Hotline  -  888-562-4357 


Circle  105  on  product  info  card 


hospital  mortality,  BiPAP  may  also  be  used  suc- 
cessfully to  temporize  patients  who  develop  RF 
in  the  period  following  endotracheal  extuba- 
tion.  The  duration  of  BiPAP  dependency  (35  h 
in  this  study)  was  shorter  than  in  previous  tri- 
als, and.  though  this  is  speculative,  may  have 
been  minimized  by  our  performing  a  trial  of 
unassisted  breathing  each  day. 


A  Novel  Approach  to  Monitor  Tissue  Perfu- 
sion: Bladder  Mucosal  PfOj'  ^o,'  and  pH 
During  Ischemia  and  Reperfusion — Lang  JD 
Jr,  Evans  DJ.  deFigueiredo  LP.  Hays  S,  Mathru 
M,  Kramer  GC.  J  Crit  Care  1999  Jun;14(2):93- 
98. 

PURPOSE:  The  purpose  of  this  study  is  to  de- 
termine if  monitoring  urinary  bladder  P^o,,  Po,. 
and  calculated  intramucosal  pH  would  be  a  re- 
liable index  of  tissue  perfusion.  MATERIALS 
AND  METHODS:  This  nonrandomized  con- 
trolled study  was  conducted  in  a  laboratory  at  a 
university  medical  center.  Eight  immature  fe- 
male Yorkshire  pigs  were  studied  with  T-9  aor- 
tic cross-clamping  for  30  minutes  followed  by  a 
60-minute  period  of  reperfusion.  Cystotomy  was 
performed  for  placement  of  a  Foley  catheter 
and  Paratrend  7  Oj/COj  sensor.  RESULTS: 
Baseline  hemodynamic  and  metabolic  measure- 
ments were  obtained  along  with  measurements 


of  bladder  mucosal  P„,  and  P^.,,,  (meaniSEM). 
Blood  flow  measured  with  microspheres  con- 
firmed absence  of  blood  flow  during  occlusion 
and  hyperemia  during  reperfusion.  Bladder  mu- 
cosal Pq,  decreased  from  42±  14.0  mm  Hg  (5.6 
kPa)  to  1.3  ±1.3  mm  Hg  (1.4  kPa)  during  the 
30-minute  interval  of  ischemia.  This  was  fol- 
lowed by  an  increase  of  bladder  Pq,  to  greater 
than  baseline  values  at  the  end  of  the  reperfu- 
sion period.  Bladder  mucosal  P^.q,  increased 
from  57±4.7  mm  Hg  (7.6  kPa)  to  1 17±7.1  mm 
Hg  (15.6  kPa)  (p  <  0.05)  during  ischemia.  Dur- 
ing reperfusion  the  P^.,,,  returned  to  baseline 
levels  (55 ±4.0  mm  Hg  [7.3  kPa]).  Calculated 
bladder  mucosal  pH  declined  from  7.31  ±0.04 
to  7.08±0.05  (p  <  0.05)  during  the  ischemic 
period  and  after  reperfusion  pH  was  7. 1 7 ±0.03. 
CONCLUSIONS:  Monitoring  urinary  bladder 
Pq,'  Pco,.  or  calculating  pH  may  provide  a  sim- 
ple and  reliable  means  of  monitoring  tissue  per- 
fusion. 


Nocturnal  Oxygenation  During  Patient-Con- 
trolled Analgesia — Stone  JG,  Cozine  KA.  Wald 
A.  Anesth  Analg  1 999  Jul  ;89(  1 ):  1 04  - 1 1 0. 

Patient-controlled  analgesia  (PCA)  has  become 
a  standard  modality  for  the  management  of  post- 
operative pain,  although  anecdotal  reports  of 
excessive  sedation  and  respiratory  depression 
impugn  its  safety.  To  study  the  prevalence  and 


severity  of  nocturnal  hypoxemia,  we  measured 
arterial  oxygen  saturation  (Spo,)  continuously 
overnight  in  32  postoperative  patients  who  were 
receiving  morphine  via  PCA.  To  evaluate  the 
potential  benefit  of  providing  concurrent  sup- 
plemental oxygen,  the  patients  breathed  oxy- 
gen-enriched air  the  night  of  surgery  and  room 
air  the  next  night.  Patients  experienced  more 
pain  and  consumed  twice  as  much  morphine 
the  first  night.  However,  breathing  supplemen- 
tal oxygen  that  night,  the  nocturnal  mean  Sp„, 
was  99%±l%,  94%±4%  (p<0.001),  and  only 
four  patients  had  periods  of  hemoglobin  desatu- 
ration  <90%.  In  contrast,  breathing  room  air 
the  subsequent  night,  the  mean  Spo,  was  lower 
(94%  ±49!;;  p<0.001 ),  and  hypoxemia  occurred 
more  frequently  and  was  more  severe:  18  pa- 
tients experienced  episodes  of  SpQ,  <90%,  7 
patients  experienced  episodes  of  Spo,  <80%, 
and  3  patients  experienced  episodes  of  SpQ, 
<70%.  One  patient  required  resuscitation  for 
profound  bradypnea  and  cyanosis,  but  none  suf- 
fered permanent  sequelae.  We  conclude  that 
when  postoperative  patients  use  PCA  at  night, 
hypoxemia  can  be  substantial  and  oxygenation 
can  be  improved  by  providing  supplemental  ox- 
ygen. IMPLICATIONS:  Oxygen  saturation  was 
measured  postoperatively  in  patients  using  mor- 
phine patient-controlled  analgesia.  Substantial 
nocturnal  hypoxemia  occurred  in  half  of  the 
patients  while  they  breathed  room  air.  The  se- 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1417 


Abstracts 


verity  of  the  hypoxemia  was  reduced  when  pa- 
tients received  supplemental  oxygen. 

Combined  Therapy  with  Inhaled  Nitric  Ox- 
ide and  Intravenous  Vasodilators  During 
Acute  and  Chronic  Experimental  Pulmonary 
Hypertension — Aranda  M,  Bradford  KK,  Pearl 
RG.  Anesth  Analg  1999  Jul;89{l):152-158. 

Both  inhaled  nitric  oxide  (NO)  and  I.V.  vaso- 
dilators decrease  pulmonary  hypertension,  but 
the  effects  of  combination  therapy  are  unknown. 
We  studied  the  response  to  inhaled  NO  (100 
ppm)  alone,  I.V.  vasodilator  alone,  and  com- 
bined therapy  during  acute  (U46619-induced) 
and  chronic  (monocrotaline-induced)  pulmo- 
nary hypertension  in  the  pentobarbital-anesthe- 
tized  rat.  Vasodilator  doses  were  1.0,  3.2,  10, 
and  32  microg  X  kg"'  X  min'  sodium  nitro- 
prusside  (SNP);  50,  100,  150,  200,  and  300 
microg  X  kg"'  X  min"'  adenosine;  or  25,  50, 
150,  200,  and  300  ng  X  kg"'  X  min"'  prosta- 
cyclin. In  the  absence  of  I.V.  vasodilator  ther- 
apy, inhaled  NO  decreased  mean  pulmonary 
artery  pressure  without  decreasing  mean  sys- 
temic arterial  pressure.  In  both  acute  and  chronic 
pulmonary  hypertension,  the  addition  of  inhaled 
NO  to  the  largest  dose  of  adenosine  or  prosta- 
cyclin, but  not  of  SNP,  decreased  pulmonary 
artery  pressure.  Because  inhaled  NO  and  SNP 
activate  guanylyl  cyclase  and  adenosine  and 
prostacyclin  activate  adenylyl  cyclase,  the  re- 
sults suggest  that  adding  inhaled  NO  to  a  va- 
sodilator not  dependent  on  guanylyl  cyclase  may 
produce  additional  selective  pulmonary  vasodi- 
lation. IMPLICATIONS:  In  therapy  of  pulmo- 
nary hypertension,  inhaled  nitric  oxide  should 
produce  additional  selective  pulmonary  vasodi- 
lation when  combined  with  a  vasodilator  whose 
mechanism  of  action  is  not  dependent  on  cyclic 
guanosine  3 ',5 '-monophosphate. 

The  Influence  of  the  Tonsillar  Gag  on  Effi- 
cacy of  Seal,  Anatomic  Position,  Airway  Pa- 
tency, and  Airway  Protection  with  the  Flex- 
ible Laryngeal  Mask  Airway:  A  Randomized, 
Cross-Over  Study  of  Fresh  Adult  Cadavers — 
Brimacombe  JR,  Keller  C,  Gunkel  AR,  Pu- 
hringer  F.  Anesth  Analg  1999  Jul;89(l):181- 
186. 

We  conducted  a  randomized,  controlled,  cross- 
over cadaver  study  to  test  the  hypothesis  that 
the  efficacy  of  seal  for  ventilation  and  airway 
protection,  anatomic  position,  and  airway  pa- 
tency with  the  flexible  laryngeal  mask  airway 
(FLMA)  are  altered  by  the  application  of  a  Boyle 
Davis  (B-D)  gag.  We  also  determined  the  air- 
way sealing  pressure  (ASP)  at  which  the  FLMA 
prevents  aspiration  when  large  volumes  of  fluid 
are  placed  above  the  cuff.  We  studied  20  adult 
cadavers  (6-24  h  postmortem).  Efficacy  of  seal 
for  ventilation  and  airway  protection,  anatomic 
position,  and  airway  patency  were  determined 
V,  i.:h  and  without  a  B-D  gag  (two  blade  sizes:  8 


and  10  cm)  for  the  size  3,  4,  and  5  FLMA  in 
random  order.  Efficacy  of  seal  for  ventilation 
was  determined  by  measuring  the  ASP  at  an 
intracuff  pressure  of  60  cm  H^O.  Efficacy  of 
seal  for  airway  protection  was  determined  by 
flooding  the  mouth  with  55-135  mL  of  water, 
reducing  intracuff  pressure  until  aspiration  was 
detected  fiberoptically  and  measuring  ASP  at 
this  intracuff  pressure.  Anatomic  position  and 
airway  patency  were  determined  with  a  fiber- 
optic scope  at  an  intracuff  pressure  of  60  cm 
H2O.  In  addition,  in  vivo  compliance  and  ASP 
for  the  FLMA  were  measured  in  10  cadavers 
and  10  paralyzed,  anesthetized  patients.  Effi- 
cacy of  .seal  for  ventilation  and  airway  protec- 
tion, anatomic  position,  and  airway  patency  did 
not  change  with  the  application  of  a  gag  for  any 
mask  size.  The  mean  (range)  ASP  at  which 
aspiration  occurred  when  large  volumes  of  fluid 
were  placed  above  the  cuff  was  II  (7-15)  cm 
HiO.  The  ASP  for  ventilation  was  always  higher 
than  the  ASP  for  airway  protection  (p<0.0001 ). 
The  FLMA  had  similar  in  vivo  compliance  and 
ASP  in  cadavers  and  anesthetized  patients.  We 
conclude  that  efficacy  of  seal  for  ventilation 
and  airway  protection,  anatomic  position  and 
airway  patency  for  the  FLMA  are  unaffected  by 
the  application  of  a  B-D  gag  in  adults.  ASP 
should  be  >I5  cm  HjO  if  there  is  a  maximal 
risk  of  aspiration  from  above  the  cuff  IMPLI- 
CATIONS: The  flexible  laryngeal  mask  airway 
forms  an  effective  seal  for  ventilation  and  pro- 
tection of  the  airway  that  is  unaffected  by  the 
application  of  a  mouth  gag  that  provides  surgi- 
cal access  to  the  oropharynx.  The  efficacy  of 
the  seal  should  be  >  1 5  cm  HjO  if  there  is  a 
maximal  risk  of  aspiration  from  above  the  cuff 

Nitrous  Oxide  Increases  Endotracheal  Cuff 
Pressure  and  the  Incidence  of  Tracheal  Le- 
sions in  Anesthetized  Patients — Tu  HN,  Saldi 
N.  Leiutaud  T,  Bensaid  S,  Menival  V,  Duvaldes- 
tin  P.  Anesth  Analg  1999  Jul;89(l):187-190. 

The  pressure  in  air-filled  endotracheal  cuffs  in- 
creases steadily  throughout  general  anesthesia 
with  nitrous  oxide  (NjO).  High  cuff  pressures 
can  be  responsible  for  local  ischemia,  which 
may  induce  tracheal  mucosal  injury.  In  this 
study,  cuff  pressure  was  monitored  in  anesthe- 
tized patients,  and  postanesthesia  endotracheal 
lesions  were  assessed  by  endoscopy.  Sixty-five 
patients  undergoing  general  anesthesia  with  tra- 
cheal intubation  >  1  h  in  duration  were  random- 
ized into  two  groups.  The  endotracheal  tube 
cuff  was  inflated  to  30-40  cm  HjO  with  air  in 
Group  1  (n  =  33)  and  with  a  gas  mixture  (N^O 
50%  in  oxygen)  in  Group  2  (n  =  32).  At  the 
time  of  tracheal  extubation,  a  fiberoptic  exam- 
ination via  the  endotracheal  tube  was  performed 
by  an  independent  observer.  Aspects  of  trachea 
at  the  level  of  cuff  contact  area  were  scored  as 
0  =  normal,  I  =  mucosal  erythema  or  edema, 
2  =  mucosal  erosion  or  hemorrhage,  3  =  mu- 
cosal erosion  or  hemorrhage  on  both  anterior 


and  posterior  tracheal  walls.  Cuff  pressure  in- 
creased throughout  the  procedure  (p<0.01)  in 
Group  1  and  remained  stable  in  Group  2.  In 
Group  1,  tracheal  lesions  in  the  area  of  the  cuff 
were  more  frequent  than  they  were  in  Group  2 
(79%  vs.  37%;  p<0.001).  Tracheal  injury  was 
correlated  to  cuff  pressure  (r  =  0.62,  p<0.001). 
No  postoperative  respiratory  complication  was 
observed  in  any  patient.  In  patients  anesthe- 
tized with  N2O,  the  inflation  of  the  tracheal 
tube  cuff  with  a  gas  mixture  of  the  same  com- 
position as  the  inhaled  mixture  can  prevent  ex- 
cessive cuff  pressure  and  reduce  the  incidence 
of  tracheal  injury.  IMPLICATIONS:  In  patients 
anesthetized  with  nitrous  oxide,  the  inflation  of 
the  tracheal  tube  cuff  with  a  gas  mixture  of  the 
same  composition  as  the  inhaled  mixture  can 
prevent  excessive  cuff  pressure  and  reduce  the 
incidence  of  tracheal  injury. 

Comparison  of  Therapeutic  and  Subthera- 
peutic Nasal  Continuous  Positive  Airway 
Pressure  for  Obstructive  Sleep  Apnoea:  A 
Randomised  Prospective  Parallel  Trial — 
Jenkinson  C,  Davies  RJ,  Mullins  R,  Stradling 
JR.  Lancet  1999  Jun  19;353(917O):210O-2105. 

BACKGROUND:  Nasal  continuous  positive 
airway  pressure  (NCPAP)  is  widely  used  as  a 
treatment  for  obstructive  sleep  apnoea.  How- 
ever, to  date  there  are  no  randomised  controlled 
trials  of  this  therapy  against  a  well-matched  con- 
trol. We  undertook  a  randomised  prospective 
parallel  trial  of  therapeutic  NCPAP  for  obstruc- 
tive sleep  apnoea  compared  with  a  control  group 
on  subtherapeutic  NCPAP.  METHODS:  Men 
with  obstructive  sleep  apnoea,  defined  as  an 
Epworth  sleepiness  score  of  10  or  more  and  ten 
or  more  dips  per  h  of  more  than  4%  S„o,  caused 
by  obstructive  sleep  apnoea  on  overnight  sleep 
study,  were  randomly  assigned  therapeutic  NC- 
PAP or  subtherapeutic  NCPAP  (about  1  cm 
HjO)  for  1  month.  Primary  outcomes  were  sub- 
jective sleepiness  (Epworth  sleepiness  score), 
objective  sleepiness  (maintenance  of  wakeful- 
ness test),  and  SF-36  questionnaire  measure- 
ments of  self-reported  functioning  and  well-be- 
ing. FINDINGS:  107  men  entered  the  study:  53 
received  subtherapeutic  NCPAP  and  54  thera- 
peutic NCPAP.  Use  of  NCPAP  by  the  two  treat- 
ment groups  was  similar:  5.4  h  (therapeutic) 
and  4.6  h  (subtherapeutic)  per  night.  Subthera- 
peutic NCPAP  did  not  alter  the  overnight  num- 
ber of  S„02  dips  per  h  compared  with  baseline, 
and  thus  acted  as  a  control.  Therapeutic  NC- 
PAP was  superior  to  subtherapeutic  NCPAP  In 
all  primary  outcome  measures.  The  Epworth 
score  was  decreased  from  a  median  of  15.5  to 
7.0  on  therapeutic  NCPAP,  and  from  15.0  to 
13.0  on  subtherapeutic  NCPAP  (between  treat- 
ments, p<0.000l).  Mean  maintenance-of- 
wakefulness  time  increased  from  22.5  to  32.9 
min  on  therapeutic  NCPAP  and,  not  signifi- 
cantly, from  20.0  to  23.5  min  on  subtherapeutic 
NCPAP  (between  treatments  p<0.005).  Effect 


1418 


Respiratory  Care  •  December  1999  Vol  44  No  12 


sizes  for  SF-36  measures  of  energy  and  vitality 
were  1 .68  (therapeutic)  and  0.97  (subtherapeu- 
tic) NCPAP  (between  treatments  p<0.0001). 
For  mental  summary  score,  the  corresponding 
values  were  1.02  and  0.4  (between  treatments 
p=0.002).  INTERPRETATION:  Therapeutic 
NCPAP  reduces  excessive  daytime  sleepiness 
and  improves  self-reported  health  status  com- 
pared with  a  subtherapeutic  control.  Compared 
with  controls,  the  effects  of  therapeutic  NCPAP 
are  large  and  confirm  previous  uncontrolled  clin- 
ical observations  and  the  results  of  controlled 
trials  that  used  an  oral  placebo. 

Randomized  Placebo-Controlled  Trial  of  a 
42-Day  Tapering  Course  of  Dexamethasone 
To  Reduce  the  Duration  of  Ventilator  De- 
pendency in  Very  Low  Birth  Weight  In- 
fants—Kothadia  JM,  O'Shea  TM,  Roberts  D, 
Auringer  ST,  Weaver  RG,  Dillard  IS.  Pediat- 
rics 1999  Jul;104(l  Pt  l):22-27. 

Objective.  To  assess  the  effect  on  duration  of 
ventilator  dependency  of  a  42-day  tapering 
course  of  dexamethasone  in  very  low  birth 
weight  neonates.  Methods.  Infants  (N  =  118) 
were  assigned  randomly,  within  birth  weight/ 
gender  strata,  to  treatment  with  either  a  42-day 
tapering  course  of  dexamethasone  or  an  equal 
volume  of  saline  as  placebo.  Entry  criteria  were 
1)  birth  weight  <1501  g;  2)  age  between  15 
and  25  days;  3)  <I0%  decrease  in  ventilator 
settings  for  24  hours  and  F,o,  a  0.3;  4)  absence 
of  patent  ductus  arteriosus,  sepsis,  major  con- 
genital malformation,  congenital  heart  disease; 
and  5)  no  evidence  of  maternal  HIV  or  hepatitis 
B  infection.  The  dosage  schedule  was  0.25 
mg/kg  bid  for  3  days,  then  0.15  mg/kg  bid  for 
3  days,  then  a  10%  reduction  in  the  dose  every 
3  days  until  a  dose  of  0. 1  mg/kg  had  been  given 
for  3  days,  from  which  time  a  dose  of  0. 1  mg/kg 
qod  was  continued  until  42  days  after  entry. 
The  primary  endpoint  was  the  number  of  days 
on  assisted  ventilation  after  study  entry.  Sec- 
ondary outcomes  of  interest  included  days  on 
supplemental  oxygen,  days  of  hospitalization, 
and  potential  adverse  effects,  such  as  infection, 
gastrointestinal  bleeding,  left  ventricular  hyper- 
trophy, and  severe  retinopathy  of  prematurity. 
Results.  Infants  in  the  dexamethasone-  and  pla- 
cebo-treated groups  were  similar  in  terms  of 
baseline  attributes,  including  birth  weight,  ges- 
tational age,  gender,  race,  and  ventilator  set- 
tings at  entry.  Infants  treated  with  dexametha- 
sone were  on  assisted  ventilation  and 
supplemental  oxygen  for  fewer  days  after  study 
entry  (median  days  on  ventilator,  5th  and  95th 
percentiles,  13  [1-64]  vs  25  [6-104];  days  on 
oxygen,  59  [6-247]  vs  100  [1 1-346]).  No  dif- 
ferences were  found  in  risk  of  death,  infection, 
or  severe  retinopathy.  In  subgroup  analyses,  the 
association  of  dexamethasone  with  more  rapid 
weaning  from  the  ventilator  was  weaker  among 
infants  enrolled  before  the  16th  day  of  life,  in- 
fants with  chest  radiographs  showing  cystic 


RESEARCH  PNEUMOTACH  SYSTEM 

complete  flow  measurement  system  instrumentation  module 


RSS  100HR  Research  Pneumotach  System  with 
Hans  Rudolph  linear  pneumotach 


Model  RSS  100HR  for  the  Hans  Rudolph  Linear  &  Bi-directional 
screen  Pneumotachs  in  8  flow  ranges 

Model  RSS  100  For  the  Fixed-Orifice  Pneumotachs  available  in 

Adult  &  Neonatal 

Measures  gas  flow  using  the  differential-pressure  method 

Windows'"  software  for  displaying,  storing  and  reviewing  data 

System  is  fuliy  functional  as  a  stand-alone  device 

LCD  screen  displays  waveform  and  parameter  data  in  real  time 

Embedded  microprocessor  calculates  flow  rates  and  provides 

correction  for  gas  density,  viscosity,  temperature,  barometric 

pressure,  and  airway  pressure 

Calculates  over  15  ventilatory  parameters 

Integrated  breath  detection  algorithm  automatically  detects 

start  and  end  of  breath 

Built-in  linearization  routine  calibration  function  for  Rudolph  Pneumotachs 

Serial  RS232  and  analog  outputs  provided  for  data  collection 

HANS  RUDOLPH,  inc. 

MAKERS  OF  RESPIRATORY  VALVES  SINCE  t93B 

TEL:  (816)  363-5522  U.S.A.  &  CANADA  (800)  456-6695 
FAX:  816-822-1414   E-Mait:  hrl@rudolphkc.com    www.rudolphkc.com 
7205  CENTRAL,  KANSAS  CWf,  MISSOURI  64114  U.S.A. 


Circle  120  on  product  Info  card 


changes  and/or  hyperinflation,  and  infants  re- 
quiring an  F|o,  s  0.7  or  a  peak  inspiratory 
pressure  a  19  at  study  entry.  Conclusions.  A 
42-day  tapering  course  of  dexamethasone  de- 
creases the  duration  of  ventilator  and  oxygen 
dependency  in  very  low  birth  weight  infants 
and  is  not  associated  with  an  increased  risk  of 
short-term  adverse  effects. 


A  Three-Day  Course  of  Dexamethasone 
Therapy  To  Prevent  Chronic  Lung  Disease 
in  Ventilated  Neonates:  A  Randomized  Tri- 
al—Garland JS,  Alex  CP,  Pauly  TH,  White- 
head VL,  Brand  J,  Winston  JF,  et  al.  Pediatrics 
1999  Jul;  104(1  Pt  l):91-99. 

Background.  Although  several  trials  of  early 
dexamethasone  therapy  have  been  completed  to 
determine  if  such  therapy  would  reduce  mor- 
tality and  chronic  lung  disease  (CLD)  in  infants 
with  respiratory  distress,  optimal  duration  and 
side  effects  of  such  therapy  remain  unknown. 
Purpose.  The  purpose  of  this  study  was:  1 )  to 
determine  if  a  3-day  course  of  early  dexameth- 
asone therapy  would  reduce  CLD  and  increase 
survival  without  CLD  in  neonates  who  received 
surfactant  therapy  for  respiratory  distress  syn- 
drome and  2)  to  determine  adverse  effects  as- 
sociated with  such  therapy.  Design.  This  was  a 
prospective  multicenter  randomized  trial  com- 
paring a  3-day  course  of  dexamethasone  ther- 


apy beginning  at  24  to  48  hours  of  life  to  pla- 
cebo therapy.  Two  hundred  forty-one  neonates 
(dexamethasone  n  =  118,  placebo  n  =  123), 
who  weighed  between  500  g  and  1500  g,  re- 
ceived surfactant  therapy,  and  were  at  signifi- 
cant risk  for  CLD  or  death  using  a  model  to 
predict  CLD  or  death  at  24  hours  of  life,  were 
enrolled  in  the  trial.  Infants  randomized  to  re- 
ceive early  dexamethasone  were  given  6  doses 
of  dexamethasone  at  12-hour  intervals  begin- 
ning at  24  to  48  hours  of  life.  The  primary 
outcomes  compared  were  survival  without  CLD 
and  CLD.  CLD  was  defined  by  the  need  for 
supplemental  oxygen  at  the  gestational  age  of 
36  weeks.  Complication  rates  and  adverse  ef- 
fects of  study  drug  therapy  were  also  compared. 
Results.  Neonates  randomized  to  early  dexa- 
methasone treatment  were  more  likely  to  sur- 
vive without  CLD  (RR:  1.3;  95%  CI:  1.03,  1.7) 
and  were  less  likely  to  develop  CLD  (RR:  0.6; 
CI:  0.3,  0.  98).  Mortality  rates  were  not  signif- 
icantly different.  Subsequent  dexamethasone 
therapy  use  was  less  in  early  dexamethasone- 
treated  neonates  (RR:  0.8;  CI:  0.7,  0.96).  Very 
early  (s  7  days  of  life)  intestinal  perforations 
were  more  common  among  dexamethasone- 
treated  neonates  (8%  vs  1%).  Conclusion.  We 
conclude  that  an  early  3-day  course  of  dexa- 
methasone therapy  increases  survival  without 
CLD,  reduces  CLD,  and  reduces  late  dexameth- 
asone therapy  in  high-risk,  low  birth  weight 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1419 


Abstracts 


infants  who  receive  surfactant  tiierapy  for  re- 
spiratory distress  syndrome.  Potential  benefits 
of  early  dexamethasone  therapy  at  the  dosing 
schedule  used  in  this  trial  need  to  be  weighed 
against  the  risk  for  early  intestinal  perforation. 

Effect  of  Mechanical  Ventilation  on  Inflam- 
matory Mediators  in  Patients  with  Acute  Re- 
spiratory Distress  Syndrome:  A  Randomized 
Controlled  Trial — Ranieri  VM,  Suter  PM,  Tor- 
torella  C,  De  Tullio  R,  Dayer  JM,  Brienza  A,  et 
al.  JAMA  1999  Jul  7;282(1):54-6I. 

CONTEXT:  Studies  have  shown  that  an  inflam- 
matory response  may  be  elicited  by  mechanical 
ventilation  used  for  recruitment  or  derecruit- 
ment  of  collapsed  lung  units  or  to  overdistend 
alveolar  regions,  and  that  a  lung-protective  strat- 
egy may  reduce  this  response.  OBJECTIVE: 
To  test  the  hypothesis  that  mechanical  ventila- 
tion induces  a  pulmonary  and  systemic  cyto- 
kine response  that  can  be  minimized  by  limit- 
ing recruitment  or  derecruitment  and 
overdistention.  DESIGN  AND  SETTING:  Ran- 
domized controlled  trial  in  the  intensive  care 
units  of  2  European  hospitals  from  November 
1995  to  February  1998.  with  a  28-day  follow- 
up.  PATIENTS:  Forty-four  patients  (mean  [SD] 
age,  50  [18]  years)  with  acute  respiratory  dis- 
tress syndrome  were  enrolled.  7  of  whom  were 
withdrawn  due  to  adverse  events.  INTERVEN- 
TIONS: After  admission,  volume-pressure 
curves  were  measured  and  bronchoalveolar  la- 
vage and  blood  samples  were  obtained.  Patients 
were  randomized  to  either  the  control  group 
(n  =  19):  tidal  volume  to  obtain  normal  values 
of  arterial  carbon  dioxide  tension  (35-40  mm 
Hg)  and  positive  end-expiratory  pressure 
(PEEP)  producing  the  greatest  improvement  in 
arterial  oxygen  saturation  without  worsening  he- 
modynamics; or  the  lung-protective  strategy 
group  (n  =  18):  tidal  volume  and  PEEP  based 
on  the  volume-pressure  curve.  Measurements 
were  repeated  24  to  30  and  36  to  40  hours  after 
randomization.  MAIN  OUTCOME  MEA- 
SURES: Pulmonary  and  systemic  concentra- 
tions of  inflammatory  mediators  approximately 
36  hours  after  randomization.  RESULTS:  Phys- 
iological characteristics  and  cytokine  concen- 
trations were  similar  in  both  groups  al  random- 
ization. There  were  significant  differences 
(mean  ISD])  between  the  control  and  lung-pro- 
tective strategy  groups  in  tidal  volume  (11.1 
[1.3]  vs  7.6  1 1.1 1  mL/kg),  end-inspiratory  pla- 
teau pressures  (31 .0  [4.5]  vs  24.6[2.4]  cm  H,0), 
and  PEEP  (6.5[l.7]  vs  14.8  [2.7]  cm  H3O)  (p< 
O.(X)l).  Patients  in  the  control  group  had  an 
increase  in  bronchoalveolar  lavage  concentra- 
tions of  inlerleukin  (IL)  IB,  IL-6,  and  IL-I  re- 
ceptor agonist  and  in  both  bronchoalveolar  la- 
vage and  plasma  concentrations  of  tumor 
necrosis  factor  (TNF)  a.  IL-6,  and  TNF-  a. 
receptors  over  36  hours  (p<  0.05  for  all).  Pa- 
tients in  the  lung-protective  strategy  group  had 
1  reduction  in  bronchoalveolar  lavage  concen- 


trations of  polymorphonuclear  cells,  TNF-  a, 
IL-IB,  soluble  TNF-  a  receptor  55,  and  IL-8. 
and  in  plasma  and  bronchoalveolar  lavage  con- 
centrations of  IL-6,  soluble  TNF-  a  receptor 
75,  and  IL-1  receptor  antagonist  (p<  0.05).  The 
concentration  of  the  inflammatory  mediators  36 
hours  after  randomization  was  significantly 
lower  in  the  lung-protective  strategy  group  than 
in  the  control  group  (p<  0.05).  CONCLU- 
SIONS: Mechanical  ventilation  can  induce  a 
cytokine  response  that  may  be  attenuated  by  a 
strategy  to  minimize  overdistention  and  recruit- 
ment/derecruitment  of  the  lung.  Whether  these 
physiological  improvements  are  associated  with 
improvements  in  clinical  end  points  should  be 
determined  in  future  studies. 

Effect  of  a  Soft  Boston  Orthosis  on  Pulmo- 
nary Mechanics  in  Severe  Cerebral  Palsy — 

Leopando  MT,  Moussavi  Z,  Holbrow  J,  Cher- 
nick  V,  Pasterkamp  H,  Rempel  G.  Pediatr 
Pulmonol  1999  Jul:28(l):53-58. 

Spinal  braces  such  as  the  Soft  Boston  Orthosis 
(SBO)  help  stabilize  scoliosis  and  improve  sit- 
ting, positioning,  and  head  control  in  individu- 
als with  cerebral  palsy.  However,  their  impact 
on  pulmonary  mechanics  in  this  population  has 
not  been  studied.  We  examined  the  effect  of  a 
Soft  Boston  Orthosis  on  the  pulmonary  mechan- 
ics and  gas  exchange  in  12  children  and  young 
adults  (5-23  years  of  age)  with  severe  cerebral 
palsy.  Pulmonary  resistance,  compliance,  tidal 
volume,  minute  ventilation,  work  of  breathing, 
oxygen  saturation,  and  end-tidal  CO,  tension 
were  measured  with  the  subjects  seated  both 
with  and  without  the  orthosis  and  in  the  supine 
position  without  the  orthosis.  There  were  no 
significant  differences  in  the  measured  param- 
eters when  comparing  subjects  with  and  with- 
out their  orthoses  in  the  sitting  or  in  the  supine 
position.  As  would  be  expected  in  individuals 
with  severe  cerebral  palsy,  pulmonary  resi.stance 
was  increased  (7.33  cm  H^O/L/s)  and  compli- 
ance was  decreased  (0. 12  L/cm  HiO)  compared 
to  reported  normal  values.  Work  of  breathing 
was  greatest  in  the  sitting  position  without  the 
orthosis  (1.2  dynes/cm),  suggesting  that  the  im- 
proved positioning  achieved  with  the  orthosis 
may  decrease  the  work  of  breathing.  We  con- 
clude that  the  application  of  a  Soft  Boston  Or- 
thosis does  not  impact  negatively  on  pulmonary 
mechanics  and  gas  exchange  in  young  people 
with  severe  cerebral  palsy. 

Infant  Lung  Function  After  Inhaled  Nitric 
Oxide  Therapy  for  Persistent  Pulmonary  Hy- 
pertension of  the  Newborn — Dobyns  EL, 
Griebel  J,  Kinsella  JP,  Abman  SH,  Accurso 
FJ.  Pediatr  Pulmonol  1999  Jul:28(l):24-.30. 

Our  objectives  were  to  determine  whether  the 
use  of  inhaled  nitric  oxide  (iNO)  for  severe 
persistent  pulmonary  hypertension  of  the  new- 
born (PPHN)  causes  impaired  lung  function  dur- 


ing infancy.  We  therefore  performed  a  prospec- 
tive study  of  lung  function  in  22  infants  after 
neonatal  intensive  care  unit  (NICU)  discharge 
who  had  been  treated  for  severe  persistent  pul- 
monary hypertension  of  the  newborn  (PPHN) 
with  (n  =  15)  or  without  (n  =  7)  iNO,  and 
compared  these  findings  in  lung  function  to  those 
of  healthy  control  infants  (n  =  18).  Five  infants 
with  interstitial  lung  disease  (ILD)  were  in- 
cluded to  assure  that  the  pulmonary  function 
tests  (PFT)  were  sensitive  enough  to  detect  abr 
normalities  of  lung  function  in  this  age  group. 
We  measured  passive  respiratory  mechanics  and 
functional  residual  capacity  (FRC)  using  a  com- 
mercially available  system.  All  data  were  ex- 
pres.sed  as  means  and  standard  deviation.  Sta- 
tistical analysis  was  performed  by  analysis  of 
variance  (ANOVA).  A  Bonferroni  multiple 
comparisons  test  was  used  for  variables  that 
showed  overall  group  differences.  Twenty-two 
infants  were  studied  during  follow-up  4-12 
months  after  NICU  discharge.  None  of  the  in- 
fants were  actuely  ill,  and  only  one  infant  was 
on  0.25  L  of  oxygen  per  minute  at  the  lime  of 
study.  We  found  no  differences  in  lung  func- 
tion between  the  treatment  groups  (iNO  -I-  me- 
chanical ventilation  (MV),  or  MV  alone),  or 
between  either  treatment  group  and  healthy  con- 
trol infants  of  the  same  age.  We  were  able  to 
detect  significant  differences  in  functional  re- 
sidual capacity  adjusted  for  weight  or  height, 
and  compliance  of  the  respiratory  system  ad- 
justed for  weight  or  lung  volume  in  the  ILD 
infants  compared  to  the  healthy  controls  or  in- 
fants who  had  PPHN,  indicating  that  these  PFTs 
were  sensitive  enough  to  determine  abnormal 
lung  function  in  this  age  group.  We  conclude 
that  inhaled  nitric  oxide  therapy  for  the  treat- 
ment of  severe  PPHN  does  not  alter  lung  func- 
tion as  determined  by  lung  volume  and  passive 
respiratory  mechanics  measurements  during 
early  infancy. 

Outpatient  Exercise  Training  in  Children 
with  Cystic  Fibrosis:  Physiological  Effects, 
Perceived  Competence,  and  Acceptability — 

Gulmans  VA.  de  Meer  K,  Brackel  HJ,  Faber 
JA,  Berger  R,  Helders  PJ.  Pediatr  Pulmonol 
1999  Jul:28(l):39-46. 

Exercise  training  is  currently  advocated  as  part 
of  the  treatment  of  patients  with  cystic  fibrosis 
(CF).  However,  data  are  few  that  document 
physiologic  benefits  or  changes  in  patients'  per- 
ceptions of  long-term  training  programs  in  chil- 
dren with  CF.  The  aim  of  this  study  was  to 
investigate  the  effects  and  acceptability  of  a 
home  cycling  program  in  children  with  CF. 
Fourteen  patients  (9  boys,  5  girls)  with  CF,  mean 
(SD)  age  14.1  (2.0)  years,  with  mild  to  moder- 
ate impairment  of  lung  function  (forced  expi- 
ratory volume  in  1  s,  mean  (SD)  58.3  (16.3)% 
of  predicted)  were  studied  for  1  year.  The  first 
half  of  the  study  year  was  used  to  obtain  base- 
line values  at  0  and  6  months.  During  the  sec- 


1420 


Respiratory  Care  •  December  1999  Vol  44  No  12 


The 

Gold  Standard 
just  got  -- 


'^■-  .i:-^m--m 


AewChamb'er  ' 


Continuing  with  tiie  tradition  of 
innovation  -  IMonaghan  i\Aedicai 
is  proud  to  introduce  the  newly       / 
designed  AeroChamber Plus^'^         I 
Vaived  Holding  Chamber  ("VHC").  J 

Improved  aerodynamic  body. 

Delivering  medication  is  serious  business.  IVIonaghan 
Medical's  new  design  of  the  AeroChamber  Plus™ 
VHC  delivers  more  aerosol  particles  to  your 
patient's  respiratory  system. 

New  valve  and  baffle  system. 

The  industry  standard  has  been  redefined  to  deliver 
more  medication  more  efficiently.  Our  new  valve  system 
allows  flow  in  one  direction  only  -  to  your  patient's  lungs. 

Completely  redesigned  mask. 

A  reliable  seal  is  critical  for  aerosol  delivery  and  efficient  ventilation 
with  children.  Our  new  masks  provide  low  resistance  inhalation  and 
exhalation  with  the  new  tamper  proof  valve.  Dead  space  is  minimized 
with  the  comfortable  fit  of  our  soft  1 00%  silicone  masks.  The  anatomical 
designs  fit  children  from  infant  to  toddler  and  older. 


Visit  Us  at  AARC,  Booth  #1031 


monaghan 


Monaghan  Medical  Corporation 

PO  Box  2805  •  Piattsburgh.  NY  12901-0299 
Customer  Service  800-833-9653 

©1999  Monaghan  Medical  Corporation. 
All  rights  reserved. 


AeroChamber  Plus'''  VHC 
with  FLOWSIGnaff  Whistle 


MEDIUM 

AeroChamber  Plus"  VHC  with 

ComforlSeal'"  Mask 


AeroQuimber  -j 

/  A.. 


SMALL 

AeroChamber  Plus"  VHC  with 

ComfortSeal"  Mask 


LARGE 

AeroChamber  Plus"  VHC 
with  FLOWSIGnal"^  Whistle 
and  ComfortSeal "  Mask 


Circle  131  on  product  info  card 

Visit  Rnnth  imi   in  I  ac  V/onac 


A 


Abstracts 


ond  half  of  the  year,  a  cycle  program  was  car- 
ried out  5  times  a  week,  for  20  min  each  day  at 
a  level  of  work  that  resulted  in  a  heart  rate  of 
140-160  beats/min.  Once  a  week  the  cycle  pro- 
gram was  supervised  by  a  physiotherapist.  Mea- 
surements were  repeated  at  12  months.  Effects 
of  the  exercise  program  were  measured  in  terms 
of  lung  function,  nutritional  status,  growth,  mus- 
cle strength,  exercise  performance,  perceived 
competence,  and  attitude  towards  the  training 
program.  Differences  between  the  changes  dur- 
ing the  6-month  training  period  as  compared  to 
the  6-month  control  period  were  analyzed  by 
multivariate  statistics  and  nonparametric  tests. 
Statistically  significant  differences  (p  <  0.05) 
between  the  two  periods  were  found  with  re- 
spect to  muscle  strength  of  knee  extensors  and 
ankle  dorsiflexors,  and  with  respect  to  maximal 
oxygen  consumption  per  kg  body  weight  as  well 
as  per  kg  fat  free  mass.  All  changes  were  pos- 
itive. No  adverse  effects  were  found.  Perceived 
competence  showed  significant  positive  changes 
in  feelings  about  physical  appearance,  general 
self-worth,  and  Total  Perceived  Competence 
Score.  Scores  concerning  perceived  acceptabil- 
ity of  the  program  were  significantly  lower  at 
the  end  of  the  training  period;  however,  pa- 
tients reported  that  they  did  want  to  continue 
with  other  sorts  of  training.  We  conclude  that 
an  exercise  training  program  in  the  home  can 
produce  beneficial  effects  on  oxygen  consump- 
tion, muscle  force,  and  perceived  competence 
in  children  with  CF.  However,  acceptability  of 
the  program  was  low,  suggesting  that  long-term 
adherence  would  be  poor,  and  hence,  other  sorts 
of  training  need  to  be  identified. 

Cost  Minimisation  Analysis  of  Provision  of 
Oxygen  at  Home:  Are  the  Drug  Tariff  Guide- 
lines Cost  Effective?— Heaney  LG,  McAllis- 
terD,MacMahonJ.BMJ  1999 Jul  3:319(7201): 
19-23. 

Objectives:  To  determine  the  level  of  oxygen 
cylinder  use  at  which  it  becomes  more  cost  ef- 
fective to  provide  oxygen  by  concentrator  at 
home  in  Northern  Ireland,  and  to  examine  po- 
tential cost  savings  if  cylinder  use  above  this 
level  had  been  replaced  by  concentrator  in  1996. 
Design:  Cost  minimisation  analysis.  Setting: 
Area  health  boards  in  Northern  Ireland.  Main 
outcome  measures:  Cost  effective  cut  off  point 
for  switch  to  provision  of  oxygen  from  cylinder 
to  concentrator.  Potential  maximum  and  mini- 
mum savings  in  Northern  Ireland  (sensitivity 
analysis)  owing  to  switch  to  more  cost  effective 
strategy  on  the  basis  of  provision  of  cylinders 
in  1996.  Results:  In  Northern  Ireland  it  is  cur- 
rently cost  effective  to  provide  oxygen  by  con- 
centrator when  the  patient  is  using  three  or  more 
cylinders  per  month  independent  of  the  dura- 
tion of  the  prescription.  More  widespread  use 
of  concentrators  at  this  level  of  provision  is 
likely  to  lead  to  a  cost  saving.  Conclusions:  The 
Fjrug  Tariff  prescribing  guidelines,  advocating 


that  provision  of  oxygen  by  concentrator  be- 
comes cheaper  when  2 1  cylinders  are  being  used 
per  month-are  currently  inaccurate  in  Northern 
Ireland.  Regional  health  authorities  should  re- 
view their  current  arrangements  for  provision 
of  oxygen  at  home  and  perform  a  cost  analysis 
to  determine  at  what  level  it  becomes  more  cost 
effective  to  provide  oxygen  by  concentrator. 

Usefulness  of  the  Medical  Research  Council 
(MRC)  Dyspnoea  Scale  As  a  Measure  of  Dis- 
ability in  Patients  with  Chronic  Obstructive 
Pulmonary  Disease — Bestall  JC,  Paul  EA,  Gar- 
rod  R,  Gamham  R,  Jones  PW,  Wedzicha  JA. 
Thorax  1999  Jul:54(7):581-586. 

BACKGROUND:  Methods  of  classifying 
chronic  obstructive  pulmonary  disease  (COPD) 
depend  largely  upon  spirometric  measurements 
but  disability  is  only  weakly  related  to  mea- 
surements of  lung  function.  With  the  increased 
use  of  pulmonary  rehabilitation,  a  need  has  been 
identified  for  a  simple  and  standardised  method 
of  categorising  disability  in  COPD.  This  study 
examined  the  validity  of  the  Medical  Research 
Council  (MRC)  dyspnoea  scale  for  this  pur- 
pose. METHODS:  One  hundred  patients  with 
COPD  were  recruited  from  an  outpatient  pul- 
monary rehabilitation  programme.  Assessments 
included  the  MRC  dyspnoea  scale,  spirometric 
tests,  blood  gas  tensions,  a  shuttle  walking  test, 
and  Borg  scores  for  perceived  breathlessness 
before  and  after  exercise.  Health  status  was  as- 
sessed using  the  St  George's  Respiratory  Ques- 
tionnaire (SGRQ)  and  Chronic  Respiratory 
Questionnaire  (CRQ).  The  Nottingham  Ex- 
tended Activities  of  Daily  Living  (EADL)  score 
and  Hospital  Anxiety  and  Depression  (HAD) 
score  were  also  measured.  RESULTS:  Of  the 
patients  studied,  32  were  classified  as  having 
MRC  grade  3  dyspnoea,  34  MRC  grade  4  dys- 
pnoea, and  34  MRC  grade  5  dyspnoea.  Patients 
with  MRC  grades  1  and  2  dyspnoea  were  not 
included  in  the  study.  There  was  a  significant 
association  between  MRC  grade  and  shuttle  dis- 
tance, SGRQ  and  CRQ  scores,  mood  state  and 
EADL.  Forced  expiratory  volume  in  one  sec- 
ond (FEV 1 )  was  not  associated  with  MRC  grade. 
Multiple  logistic  regression  showed  that  the  de- 
terminants of  disability  appeared  to  vary  with 
the  level  of  disability.  Between  MRC  grades  3 
and  4  the  significant  covariates  were  exercise 
performance,  SGRQ  and  depression  score, 
whilst  between  grades  4  and  5  exercise  perfor- 
mance and  age  were  the  major  determinants. 
CONCLUSIONS:  The  MRC  dyspnoea  scale  is 
a  simple  and  valid  method  of  categorising  pa- 
tients with  COPD  in  terms  of  their  disability 
that  could  be  used  to  complement  FEV,  in  the 
classification  of  COPD  severity. 

Evaluation  of  the  Buccal  Component  of  Sys- 
temic Absorption  with  Inhaled  Fluticasone 
Propionate — Dempsey  OJ,  Coutie  WJ,  Wilson 


AM,  Williams  P,  Lipworth  BJ.  Thorax  1999 
Jul;54(7):614-617. 

BACKGROUND:  Inhaled  corticosteroids  have 
dose  related  systemic  effects  determined  by  oral 
(swallowed  or  oropharyngeal  absorption)  and 
lung  bioavailability.  A  study  was  undertaken  to 
evaluate  the  significance  of  oropharyngeal  ab- 
sorption for  fluticasone  propionate.  METHODS: 
Sixteen  healthy  volunteers  of  mean  age  29.3 
years  were  studied  using  an  open  randomised, 
placebo  controlled,  four  way  crossover  design. 
Treatments  were:  (a)  fluticasone  metered  dose 
inhaler  (pMDI)  250  microg,  8  puffs;  (b)  fluti- 
casone pMDI  250  microg,  8  puffs  +  mouth 
rinsing/gargling  (water);  (c)  fluticasone  pMDI 
250  microg,  8  puffs  -I-  mouth  rinsing/gargling 
(charcoal);  and  (d)  placebo  pMDI,  8  puffs  -I- 
mouth  rinsing/gargling  (water).  Overnight 
(ONUC)  and  early  morning  (EMUC)  urinary 
Cortisol/creatinine  ratios  and  8  am  serum  Corti- 
sol (SC)  levels  were  measured.  RESULTS:  Sig- 
nificant (p<  0.05)  suppression  of  ONUC, 
EMUC,  and  SC  occurred  with  each  active  treat- 
ment compared  with  placebo.  The  mean  values 
(95%  CI  for  difference  from  placebo)  were:  (a) 
ONUC  (nmol/mmol):  fluticasone  (2.  8,  95%  CI 
3.6  to  7.9),  fluticasone  -I-  water  (3.1,  95%  CI 
3.3  to  7.7),  fluticasone  -I-  charcoal  (2.3,  95%  CI 
4.1  to  8.5);  placebo  (8.6);  (b)  EMUC  (nmol/ 
mmol):  fluticasone  (5.6,  95%  CI  8.4  to  24.5), 
fluticasone  -I-  water  (7.6,  95%  CI  6.6  to  22.4); 
fluticasone  -I-  charcoal  (5.6, 95%  CI  8.7  to  24.5); 
placebo  (22.1).  There  were  no  significant  dif- 
ferences between  active  treatments.  The  num- 
bers of  subjects  with  an  overnight  urinary  Cor- 
tisol of  <20  nmol/10  hours  were  0  (placebo), 
11  (fluticasone),  12  (fluticasone  -I-  water),  and 
13  (fluticasone  +  charcoal).  CONCLUSIONS: 
Oropharyngeal  absorption  of  fluticasone  does 
not  significantly  contribute  to  its  overall  sys- 
temic bioactivity  as  assessed  by  sensitive  mea- 
sures of  adrenal  suppression.  In  view  of  almost 
complete  hepatic  first  pass  inactivation  with  flu- 
ticasone, there  is  no  rationale  to  employ  mouth 
rinsing  to  reduce  its  systemic  effects  although  it 
may  be  of  value  for  reducing  oral  candidiasis. 

Cardiogenic  Shock  (review) — Hollenberg  SM, 
Kavinsky  CJ,  Parrillo  JE.  Ann  Intern  Med  1999 
Jul  6:131(1  ):47-59. 

PURPOSE:  To  review  the  cause,  epidemiol- 
ogy, pathophysiology,  and  treatment  of  cardio- 
genic shock.  DATA  SOURCES:  A  MEDLINE 
search  of  the  English-language  reports  published 
between  1 976  and  1 998  and  a  manual  search  of 
bibliographies  of  relevant  papers.  STUDY  SE- 
LECTION: Experimental,  clinical,  and  basic  re- 
search studies  related  to  cardiogenic  shock. 
DATA  EXTRACTION:  Data  in  selected  arti- 
cles were  reviewed,  and  relevant  clinical  infor- 
mation was  extracted.  DATA  SYNTHESIS: 
Cardiogenic  shock  is  a  state  of  inadequate  tis- 
sue perfusion  due  to  cardiac  dysfunction,  most 


1422 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Wed  tilled  proi^idej 

superior  aerosol  therapy  across 

the  care  continuum 


Maximizing 

delivery  of 

Inhaled 

medications  to 

the  lungs 


Better  outcomes 
at  lower  cost 
through  contin- 
uous nebulization 
therapy 


MDILog' 


The  device  provides  the  ability 
to  monitor  compliance  and 
record  true  delivery  and 
evaluate  patient  technique. 
These  features  mal<e  it  the  ideal 
disease  management  tool  for 
asthma  and  COPD  patients. 


Circulaire™ 


Designed  for  inpatient  and 
at-home  use,  the  Circulaire's 
patented  distensible  drug 
reservoir  minimizes  waste 
while  it's  variable  resistor 
tailors  treatment  to  individual 
pediatric/  adult  patient  needs. 


HEARr"*  Nebulizers 


•'■;-■•■''(■%' 


The  high-output  extended 

mm 

aerosol  respiratory  therapy 

{HEART®}  system  is 

unsurpassed  in  delivering 

1 

continuous  nebulization  therapy 

c 

[CNT]  in  inpatient  and 

outpatient  settings. 

\mh 


A%  '  ik 


•  Records  date  and  time  of  each  use  and 
evaluates  technique 

•  Reduces  lengths  of  stay  and  increases 
staff  productivity 

•  Transmits  data  for  analysis/ 
storage  with  fast  wireless 
communications 

•  Ideal  for  use  in  acute,  subacute,  pulmonary 
rehab,  physician's  office  and  home  settings 

•  Optimum  aerosol  particle  size  for  superior 
lung  deposition 

•  Ideal  for  protocol-based  concentrated  drug 
delivery 

•  Virtual  elimination  of  systemic  reaction  to 
beta  stimulators 

•  "Biofeedback"  gauges  encourage  maximum 
patient  effort 


The  HEART®  high-output  nebulizer  — 
up  to  8  hours  of  therapy 

The  MiniHEART®  low-flow  nebulizer  — 
up  to  10  hours  of  treatment 

The  low-cost  and  low-flow  UniHEARF" 
nebulizer  —  ideal  for  Emergency 
Department  use 


Wocfntpfl 


A  leader  in  aerosol  drug  delivery  and  drug  management, 
providing  superior  results  through  productivity  gains  and  patient  outcomes 
Circle  104  on  product  Info  card  across  the  care  continuum. 

Visit  AARC  Booth  848  In  Las  Vegas 

Westmed.lnc.    3351  E.  Hemisphere  Loop,  Tucson,  Arizona  85706    Phone:  800-724-2328    Fax:  520-294-6061    www.lungdepot.com 


Abstracts 


commonly  caused  by  acute  mycKardial  infarc- 
tion. Mortality  rates  for  patients  with  cardio- 
genic shock  remain  frustralingly  high,  ranging 
from  50%  to  80%.  The  pathophysiology  of  car- 
diogenic shock  involves  a  downward  spiral: 
Ischemia  causes  myocardial  dysfunction,  which, 
in  turn,  worsens  ischemia.  Areas  of  nonfunc- 
tional but  viable  (stunned  or  hibernating)  myo- 
cardium can  also  contribute  to  the  development 
of  cardiogenic  shock.  The  key  to  achieving  a 
good  outcome  is  an  organized  approach  that 
includes  rapid  diagnosis  and  prompt  initiation 
of  therapy  to  maintain  blood  pressure  and  car- 
diac output.  Expeditious  coronary  revascular- 
ization is  crucial.  When  available,  emergency 
cardiac  catheterization  and  angioplasty  seem  to 
improve  survival.  More  recent  developments, 
such  as  placement  of  coronary  stents  and  use  of 
glycoprotein  Ilb/IIIa  antagonists,  are  promising 
but  have  not  yet  been  well  studied  in  patients 
with  cardiogenic  shock.  In  hospitals  without  di- 
rect angioplasty  capability,  stabilization  with  in- 
tra-aortic  balloon  counterpulsation  and  throm- 
bolysis followed  by  transfer  to  a  tertiary  care 
facility  may  be  the  best  option.  CONCLU- 
SIONS: Improved  understanding  of  the  patho- 
physiology of  shock  and  myocardial  infarction 
has  led  to  improved  treatment.  If  cardiogenic 
shock  is  managed  with  rapid  evaluation  and 
prompt  initiation  of  supportive  measures  and 
definitive  therapy,  outcomes  can  be  improved. 

Variation  in  Length  of  Hospital  Stay  in  Pa- 
tients with  Community-Acquired  Pneumo- 
nia: Are  Shorter  Stays  Associated  with  Worse 
Medical  Outcomes? — McCormick  D,  Fine  MJ, 
Coley  CM.  Marrie  TJ.  Lave  JR,  Obrosky  DS,  et 
al.  Am  J  Med  1999  Jul;107(l):.'i-12. 

PURPOSE:  To  assess  the  variation  in  length  of 
.stay  for  patients  hospitalized  with  community- 
acquired  pneumonia  and  to  determine  whether 
patients  who  are  treated  in  hospitals  with  shorter 
mean  stays  have  worse  medical  outcomes.  SUB- 
JECTS AND  METHODS:  We  prospectively 
.studied  a  cohort  of  1.188  adult  patients  with 
community-acquired  pneumonia  who  had  been 
admitted  to  one  community  and  three  univer- 
sity teaching  ho.spitals.  We  compared  patients' 
mean  length  of  stay,  mortality,  hospital  read- 
mission,  return  to  usual  activities,  return  to  work, 
and  pneumonia-related  symptoms  among  the 
four  study  hospitals.  All  outcomes  were  adjusted 
for  ba.seline  differences  in  severity  of  illness 
and  comorbidity.  RESULTS:  Adjusted  interho- 
spital  differences  in  mean  length  of  stay  ranged 
from  0.9  to  2.3  days  (p  <().0()l ).  When  the  risk 
of  each  medical  outcome  was  compared  be- 
tween patients  admitted  to  the  hospital  with  the 
shortest  length  of  stay  and  those  admitted  to 
longer  stay  hospitals,  there  were  no  differences 
in  mortality  |relative  risk  (RR)  =  0.7;  95%  CI, 
0.3  to  l.7|,  hospital  readmission  (RR  =  0.8; 
95%  CI,  0.5  to  1.2).  return  to  usual  activities 
!<R  =  1.1;  95%  CI,  0.9  to  1.3),  or  return  to 


work  (RR  =  1 .2;  95%  CI.  0.8  to  2.0)  during  the 
first  14  days  after  discharge,  or  in  the  mean 
numberof  pneumonia-related  symptoms  .30 days 
after  adinission  (p  =  0.54).  CONCLUSIONS: 
We  observed  substantial  interhospital  variation 
in  the  lengths  of  stay  for  patients  hospitalized 
with  community-acquired  pneumonia.  The  find- 
ing that  medical  outcomes  were  similar  in  pa- 
tients admitted  to  the  hospital  with  the  shortest 
length  of  slay  and  those  admitted  to  hospitals 
with  longer  mean  lengths  of  slay  suggests  that 
hospitals  with  longer  stays  may  be  able  to  re- 
duce the  mean  duration  of  hospitalization  for 
this  disease  without  adversely  affecting  patient 
outcomes. 

Antibiotics  in  Acute  Bronchitis:  A  Meta- 
Analysis— Bent  S,  Saint  S,  Vitlinghoff  E,  Grady 
D.  Am  J  Med  1999  Jul;107(l):62-67. 

PURPOSE:  Most  patients  with  acute  bronchitis 
who  seek  medical  care  are  treated  with  antibi- 
otics, although  the  effectiveness  of  this  inter- 
vention is  uncertain.  We  performed  a  meta- 
analysis of  randomized,  controlled  trials  to 
estimate  the  effectiveness  of  antibiotics  in  the 
treatment  of  acute  bronchitis.  SUBJECTS  AND 
METHODS:  English-language  studies  pub- 
lished January  1966  to  April  1998  were  retrieved 
using  MEDLINE,  bibliographies,  and  consulta- 
tion with  experts.  Only  randomized  trials  that 
enrolled  otherwise  healthy  patients  with  a  di- 
agnosis of  acute  bronchitis,  used  an  antibiotic 
in  the  treatment  group  and  a  placebo  in  the 
control  group,  and  provided  sufficient  data  to 
calculate  an  effect  size  were  included.  RE- 
SULTS: We  identified  eight  randomized  con- 
trolled trials  that  satisfied  all  inclusion  criteria. 
These  studies  used  one  of  three  antibiotics 
(erythromycin,  doxycycline,  trimethoprim/sul- 
famethoxazole). The  use  of  antibiotics  decreased 
the  duration  of  cough  and  sputum  production 
by  approximately  one-half  day  (summary  effect 
size  0.21;  95%  CI,  0.05  to  0.36).  For  specific 
symptoms,  there  were  nonsignificant  trends  fa- 
voring the  use  of  antibiotics:  a  decrease  of  0.4 
days  of  purulent  sputum  (95%  CI,  -0.1  to  0.8), 
a  decrease  of  0.5  days  of  cough  (95%  CI,  -0. 1 
to  1.1 ),  and  a  decrease  of  0.3  days  lost  from 
work  (95%  CI,  -0.6  to  1.1).  CONCLUSION: 
This  meta-analysis  suggests  a  small  benefit  from 
the  use  of  the  antibiotics  erythromycin,  doxy- 
cycline, or  trimethoprim/sulfamethoxazole  in 
the  treatment  of  acute  bronchitis  in  otherwise 
healthy  patients.  As  this  small  benefit  must  be 
weighed  against  the  risk  of  side  effects  and  the 
societal  cost  of  increasing  antibiotic  resistance, 
we  believe  that  the  use  of  antibiotics  is  not 
justified  in  these  patients. 

Prevention  of  Human  Diaphragm  Atrophy 
with  Short  Periods  of  Electrical  Stimula- 
tion— Ayas  NT,  McCool  FD,  Gore  R.  Lieber- 
man  SL,  Brown  R.  Am  J  Respir  Crit  Care  Med 
1999  Jun;l59(6):2018-2020. 


We  determined  whether  prolonged  complete  in- 
activation  of  the  human  diaphragm  results  in 
atrophy  and  whether  this  could  be  prevented  by 
brief  periods  of  electrical  phrenic  nerve  stimu- 
lation. We  studied  a  subject  with  high  spinal 
cord  injury  who  required  removal  of  his  left 
phrenic  nerve  pacemaker  (PNP)  and  the  rein- 
stitution  of  positive-pressure  ventilation  for  8 
mo.  During  this  time,  the  right  phrenic  nerve 
was  stimulated  30  min  per  day.  Thickness  of 
each  diaphragm  (tdi)  was  deterinined  by  ultra- 
sonography. Maximal  tidal  volume  (V,)  was 
measured  during  stimulation  of  each  diaphragm 
separately.  After  left  PNP  reimplantation.  V-, 
and  tdi  were  measured  just  before  the  resump- 
tion of  electrical  stimulation  and  serially  for  33 
wk.  On  the  previously  nonfunctioning  side,  there 
were  substantial  changes  in  Vy  (from  220  to 
600  mL)  and  tdi  (from  0. 1 8  to  0.34  cm).  On  the 
side  that  had  been  stimulated,  neither  V-,  nor  tdi 
changed  appreciably  (V,.  from  770  to  9(X)  mL; 
tdi  from  0.25  to  0.28  cm).  We  conclude  that 
prolonged  inactivation  of  the  diaphragm  causes 
atrophy  which  may  be  prevented  by  brief  peri- 
ods of  daily  phrenic  nerve  stimulation. 

Response  of  Ventilator-Dependent  Patients 
to  Different  Levels  of  Pressure  Support  and 
Proportional  Assist — Giannouli  E,  Webster  K, 
Roberts  D,  Younes  M.  Am  J  Respir  Crit  Care 
Med  1999  Jun;l59(6):1716-I725. 

The  ventilator's  response  to  the  patient's  effort 
is  quite  different  in  proportional  assist  ventila- 
tion (PAY)  and  pressure  support  ventilation 
(PSV).  We  wished  to  determine  whether  this 
results  in  different  ventilatory  and  breathing  pat- 
tern responses  to  alterations  in  level  of  support 
and,  if  so,  whether  there  are  any  gas  exchange 
consequences.  Fourteen  patients  were  studied. 
Average  elastance  (E)  was  22.8  (range,  14  -36) 
cm  H2O/L  and  average  resistance  (R)  was  15.  7 
(range,  9-21)  cm  HjO/L/s.  The  highest  PSV 
support  (PSVmax)  was  that  associated  with  a 
tidal  volume  (Vt)  of  10  ml/kg  (20.4±  3.2  cm 
H  ,0),  and  the  highest  level  of  PA  V  assist  (PA  V- 
max)  was  78±  7%  of  E  and  76±  7%  of  R. 
Level  of  assist  was  decreased  in  steps  to  the 
lowest  tolerable  level  (PSVmin,  PAVmin). 
Minute  ventilation,  V^,  ventilator  rate  (RRvent), 
and  arterial  gas  tensions  were  measured  at  each 
level.  We  also  determined  the  patient's  respi- 
ratory rate  (RRpat)  by  adding  the  number  of 
ineffective  efforts  (ARR)  to  RRvent.  There  was 
no  difference  between  PSVmin  and  PAVmin  in 
any  of  the  variables.  At  PSVmax,  V ,  was  sig- 
nificantly higher  (().90±  0.30  versus  0.5 1  ±  0. 16 
L)  and  RRvent  was  significantly  lower  (I3.2± 
3.9  versus  27.6±  10.5  min  ')  than  at  PAVmax. 
The  difference  in  RRvent  was  largely  related  to 
a  progressive  increase  in  ineffective  efforts  on 
PSV  as  level  increased  (ARR  12.1  ±  10.1  vs 
1.4±  2.1  with  PAVmax);  there  was  no  signif- 
icant difference  in  RRpat.  The  differences  in 
breathing  pattern  had  no  consequence  on  arte- 


1424 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Maximize  O2  Measurement  with 


maxtec,™  Inc. 


I^w; 


Handi 

Oxygen  .\naiyzt'r 

*  Simple 

ible 


MAKCELL 

Respiratory  Oxygen 
Replacement  Sensors 

(all  models  available) 


maxtec,™  Inc. 

FORMERLY  CERAMATEC 


Air/oxygen  mixer 

*  Low  flow  and 
High  flow  models 
available 

*  Simple  operation 

*  Low  cost 


MAXO2' 

Oxygen  Monitor 

Model  OM25ME 
Unmatched  performance 
and  reliability 
Simple  operation 
Exceptional  stability 


For  more  product  information  call:  800-748-5355 
900  West,  Suite  B,  Salt  Lake  City,  Utah  84119   phone:  801-908-1020  fax:  801-908-1050  www.maxtecinc.coni 


Circle  129  on  product  info  card 


Visit  Booth  252  in  Las  Vegas 


rial  blood  gas  tensions.  We  conclude  thai  sub- 
stantial differences  in  breathing  pattern  may  oc- 
cur between  PSV  and  PAV  and  that  these  are 
largely  artifactual  and  related  to  different  pa- 
tient-ventilator interactions. 


Risk  Factors  for  Developing  Pneumonia 
Within  48  Hours  of  Intubation — RelloJ,  Diaz 
E,  Roque  M,  Valles  J.  Am  J  Respir  Crit  Care 
Med  1999  Jun;l59(6):  1742-1746. 

Two  hundred  fifty  intubated  patients  were  fol- 
lowed during  the  first  48  h  after  intubation  in 
order  lo  identify  potential  risk  factors  for  de- 
veloping pneumonia  within  this  period.  Thirty- 
two  developed  pneumonia  during  this  time.  Uni- 
variate analysis  established  that  large  volume 
aspiration,  presence  of  sedation,  intubation 
caused  by  respiratory/cardiac  arrest  or  decrease 
in  the  level  of  consciousness,  emergency  pro- 
cedure, cardiopulmonary  resuscitation  (CPR), 
and  Glasgow  coma  score  <  9  were  significantly 
associated  with  pneumonia.  In  contrast,  prior 
infection  and  prior  antimicrobial  use  were  as- 
sociated with  a  protective  effect.  Presence  of 
subglottic  secretion  drainage  and  15  other  vari- 
ables had  no  significant  effect.  Multivariate  anal- 
ysis selected  CPR  (odds  ratio  [OR]  =  5.13, 
95%  confidence  intervals  [CI]  =  2.14,  12.26) 
and  continuous  sedation  (OR  =  4.40, 95%  CI  = 
1 .83,  10.59)  as  significant  risk  factors  for  pneu- 


monia, while  antibiotic  use  (OR  =  0.29,  95% 
CI  =  0.12.  0.69)  showed  a  protective  effect. 
Our  findings  emphasize  that  risk  factors  for 
pneumonia  change  during  the  intubation  period, 
and  preventing  pneumonia  requires  a  combined 
approach. 


Incidence  and  Mortality  After  Acute  Respi- 
ratory Failure  and  Acute  Respiratory  Dis- 
tress Syndrome  in  Sweden,  Denmark,  and 
Iceland.  The  ARF  Study  Group— Luhr  OR, 

Antonsen  K.  Karlsson  M,  Aardal  S.  Thorstein- 
sson  A.  Frostell  CG.  Bonde  J.  Am  J  Respir  Crit 
Care  Med  1999  Jun;l59(6):1849-186l. 

To  determine  the  incidence  and  90-d  mortality 
of  acute  respiratory  failure  (ARF),  acute  lung 
injury  (ALI),  and  the  acute  respiratory  distress 
.syndrome  (ARDS),  we  carried  out  an  8-wk  pro- 
spective cohort  study  in  Sweden,  Denmark,  and 
Iceland.  All  intensive  care  unit  (ICU)  admis- 
sions (n  =  13,346)  a  15  yr  of  age  were  as- 
ses.sed  between  October  6th  and  November  30th. 
1997  in  132  of  150  ICUs  with  resources  to  treat 
patients  with  intubation  and  mechanical  venti- 
lation (1  -H  MV)  >  24  h.  ARF  was  defined  as  I 
+  MV  a  24  h.  ALI  and  ARDS  were  defined 
using  criteria  recommended  by  the  American- 
European  Consensus  Conference  on  ARDS. 
Calculation  to  correct  the  incidence  for  uniden- 
tified subjects  from  nonparticipating  ICUs  was 


made.  No  correction  for  in-  or  out-migration 
from  the  study  area  was  possible.  The  popula- 
tion in  the  three  countries  >  15  yr  of  age  was 
1 1.74  million.  One  thousand  two  hundred  thir- 
ty-one ARF  patients  were  included.  287  ALI 
and  221  ARDS  patients  were  identified.  The 
incidences  were  for  ARF  77.6,  for  ALI  17.9. 
and  for  ARDS  13.5  patients  per  100.000/yr. 
Ninety-day  mortality  was  41.0%  for  ARF.  in- 
cluding ALI  and  ARDS  patients,  42.2%  for  ALI 
not  fulfilling  ARDS  criteria,  and  41.2%  for 
ARDS. 


Health  Status  in  Obstructive  Sleep  Apnea: 
Relationship  with  Sleep  Fragmentation  and 
Daytime  Sleepiness,  and  Effects  of  Continu- 
ous Positive  Airway  Pressure  Treatment — 

Bennett  LS,  Barbour  C,  Langford  B,  Stradling 
JR,  Davies  RJ.  Am  J  Respir  Crit  Care  Med 
1999  Jun;  1 59(6):  1884-1 890. 

Patients  with  obstructive  sleep  apnea  (OSA) 
have  impaired  health  status  that  improves  with 
nasal  continuous  positive  airway  pressure  (nC- 
PAP).  The  study  reported  here  explored  the  re- 
lationships between  health  status,  its  improve- 
ment with  nCPAP,  sleep  fragmentation,  and 
daytime  sleepiness.  In  the  study,  5 1  patients  (46 
male,  five  female)  ranging  from  nonsnorers  to 
individuals  with  severe  OSA  (median  apnea/ 
hypopnea  index  [AHI]  25.  90%  central  range;  I 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1425 


Abstracts 


3-  if- 


to  98)  had  polysomnography  with  microarousal 
scoring,  respiratory  arousal  scoring,  and  mea- 
surement of  pulse  transit  time.  The  Short 
Form-36  Health  Survey  (SF-36)  questionnaire 
was  administered  before  and  after  4  wk  of  nC- 
PAP  treatment;  daytime  sleepiness  was  also 
measured  before  starting  nCPAP.  Relationships 
between  pretreatment  health  status  and  sleep 
fragmentation  were  weak,  but  significant  asso- 
ciations were  found  between  all  sleep  fragmen- 
tation indices  and  health  status  improvement 
with  nCPAP  (e.g.,  arousals  according  to  the 
criteria  of  the  American  Sleep  Disorders  Asso- 
ciation versus  change  in  the  physical  compo- 
nent summary,  r  =  0.44,  p  <  0.001 ).  Compared 
with  general  population  data,  the  dimensions  of 
energy  and  vitality  and  physical  role  limitation 
were  abnormal  before  nCPAP  (p  <  0.05)  and 
normalized  with  treatment.  Sleepiness  and  pre- 
treatment SF-36  values  correlated  significantly 
(Epworth  Sleepiness  Scale  versus  energy  and 
vitality,  r  =  -0.47,  p  <  0.001;  modified  Main- 
tenance of  Wakefulness  Test  versus  energy  and 
vitality,  r  =  0.32,  p  <  0.05).  We  conclude  that 
the  health  status  of  patients  with  OS  A  improves 
with  nCPAP  and  this  improvement  correlates 
with  sleep  fragmentation  severity.  However,  the 
correlation  is  not  very  close,  which  may  reflect 
the  improvement  with  nCPAP  of  other  symp- 
toms not  directly  related  to  disease  severity. 


Evolution  of  Sleep  Apnea  Syndrome  in  Sleepy 
Snorers:  A  Population-Based  Prospective 
Study — Lindberg  E,  Elmasry  A,  Gislason  T, 
Janson  C,  Bengtsson  H,  Hetta  J,  et  al.  Am  J 
Respir  Crit  Care  Med  1999  Jun;159(6):2024- 
2027. 

This  study  followed  a  small  number  of  men 
previously  studied  polysomnographically  10  yr 
earlier  to  investigate  the  relationship  between 
the  development  of  sleep-disordered  breathing 
and  age,  weight  gain,  and  smoking.  In  1984, 
3,201  men  answered  a  questionnaire  including 
questions  about  snoring  and  excessive  daytime 
sleepiness  (EDS).  Of  those  reporting  symptoms 
related  to  obstructive  sleep  apnea  syndrome 
(OSAS),  a  random  sample  of  61  men  was  in- 
vestigated using  whole-night  polysomnography 
in  1985.  Ten  years  later,  38  men  participated  in 
the  present  follow-up,  which  included  a  struc- 
tured interview  and  polysomnography.  During 
the  lO-yr  period,  nine  men  had  been  treated  for 
OSAS.  Of  the  29  untreated  subjects,  the  num- 
ber of  men  with  OSAS,  defined  as  an  apnea- 
hypopnea  index  (AHI)  of  a  5/h,  increa.sed  from 
four  in  1985  to  13  in  1995  (p  <  0.01).  In  this 
small  sample,  no  significant  associations  were 
found  between  AAHI  (i.e.,  AHI  1995  -  AHI 
1985)  and  age,  weight  gain,  or  smoking.  We 
conclude  that,  among  this  small  group  of  indi- 
viduals who  were  selected  for  original  poly- 
somnographic  study  and  follow-up  because  they 
>  ere  thought  to  have  symptoms  of  sleep  apnea. 


sleep-disordered  breathing  became  significantly 
worse  over  time. 

Growth  of  Lungs  After  Transplantation  in 
Infants  and  in  Children  Younger  Than  3 
Years  of  Age — Cohen  AH,  Mallory  GB  Jr,  Ross 
K,  White  DK,  Mendeloff  E,  Huddleston  CB, 
Kemp  JS.  Am  J  Respir  Crit  Care  Med  1999 
Jun;159(6):1747-1751. 

We  report  serial  measurements  of  lung  volume 
and  airflow  in  small  children  after  lung  trans- 
plantation. We  expected  that  immature  lungs 
could  grow  and  develop  normal  volumes  after 
transplantation,  despite  denervation  and  immu- 
nosuppression. At  predetermined  intervals, 
functional  residual  capacity  (FRC)  and  forced 
expiratory  flow  were  measured  86  times  in  23 
recipients  younger  than  3  yr  of  age  (age  at  trans- 
plant, 13. 2±  8.4  mo;  range,  2  to  30  mo).  FRC 
was  measured  using  open-circuit  N,  washout. 
Maximal  flow  at  FRC  by  rapid  thoracoabdomi- 
nal compression  was  used  to  distinguish  be- 
tween infants  with  and  those  without  airflow 
obstruction.  The  slope  of  FRC  (in  milliliters) 
versus  body  length  (in  centimeters)  for  all  23 
recipients  studied  was  8.63.  For  those  children 
without  obstruction  (flow  at  FRC  >  0.9  FRC/s, 
n  =  16),  the  slope  of  FRC  versus  length  was 
6.61.  The  coefficient  of  variation  for  FRC  mea- 
surements for  all  infants  was  3.90±  2.80% 
(range,  0.3  to  16.9%).  We  conclude  that  in  the 
absence  of  significant  airflow  obstruction  the 
volume  of  transplanted  immature  lungs  in- 
creases at  a  rate  similar  to  that  reported  in  nor- 
mal infants. 

What  Are  Minimal  Important  Changes  for 
Asthma  Measures  in  a  Clinical  Trial? — San- 
tanello  NC,  Zhang  J,  Seidenberg  B,  Reiss  TF, 
Barber  BL.  Eur  Respir  J  1999  Jul;14(l):23-27. 

In  this  study,  the  perceptions  of  asthmatics  to 
change  in  their  disease  was  associated  with  ob- 
served changes  in  clinical  asthma  measures,  in 
order  to  identify  the  threshold  where  changes  in 
clinical  asthma  measures  are  perceivable  by  pa- 
tients. The  study  included  281  asthmatic  pa- 
tients, aged  18-63  yrs,  in  a  randomized,  pla- 
cebo-controlled clinical  trial  of  a  leukotriene 
antagonist.  Changes  were  related  in:  1 )  asthma 
symptom  scores;  2)  inhaled  beta-agonist  use;  3) 
forced  expiratory  volume  in  one  second  (FEV,); 
and  4)  peak  expiratory  flow  (PEF)  to  a  global 
question  that  queried  overall  change  in  asthma 
since  starting  the  study  drug.  Additional  anal- 
yses examined  differences  in  the  group  report- 
ing minimal  improvement  by  treatment  (active 
treatment  versus  placebo),  sex  and  age  groups. 
The  average  minimal  patient  perceivable  im- 
provement for  each  measure  was:  1 )  -0.3 1  points 
for  the  symptom  score  on  a  scale  of  0-6;  2) 
-0.81  puffs  x  day'  for  inhaled  beta-agonist  use; 
3)  0.23  L  for  FEV,;  and  4)  18.79  L  x  min'  for 
PEF.  In  general  placebo-treated  patients  and 


older  patients,  who  reported  minimal  improve- 
ment, experienced  less  mean  improvement  from 
baseline  than  active-treated  patients  and  younger 
patients,  who  reported  minimal  improvement. 
Determining  the  minimal  patient  perceivable  im- 
provement value  for  a  measure  may  be  helpful 
to  interpret  changes.  However,  interpretation 
should  be  carried  out  cautiously  when  reporting 
a  single  value  as  a  clinically  important  change. 

The  Effect  of  Patient  Technique  and  Train- 
ing on  the  Accuracy  of  Self-Recorded  Peak 
Expiratory  Flow — Gannon  PF,  Belcher  J,  Pan- 
tin  CF,  Burge  PS.  Eur  Respir  J  1999  Jul;I4(l): 
28-31. 

The  aim  of  the  study  was  to  investigate  the 
difference  between  encouraged  self-recorded 
peak  expiratory  flow  (PEF)  with  unobserved 
readings  and  to  investigate  any  long-term 
changes  in  PEF  self-recording.  Patients  were 
trained  in  the  PEF  technique  and  asked  to  keep 
2-hourly  PEF  records  until  the  next  clinic  visit. 
The  patients  PEF  were  then  rechecked  at  the 
second  clinic  visit  by  a  series  of  two  unob- 
served, an  observed  and  an  encouraged  PEF 
measurement.  A  subgroup  of  patients  were  re- 
assessed at  a  third  clinic  visit.  Forty-one  pa- 
tients produced  serial  PEF  readings.  Significant 
differences  between  unobserved  and  encouraged 
PEF  readings  were  detected;  there  was  a  mean 
decrement  of  21  L  x  min  '  and  limits  of  agree- 
ments suggested  that  the  decrement  could  be  as 
high  as  60  L  X  min"'.  Visual  and  statistical  anal- 
ysis of  the  serial  PEF  provided  showed  a  con- 
sistent deterioration  in  PEF  over  the  record  in 
54%  and  39%  of  cases,  respectively.  No  signif- 
icant differences  were  found  in  the  subgroup 
who  attended  a  third  clinic  visit.  The  results 
suggest  that  significant  inaccuracies  in  unob- 
served peak  expiratory  flow  readings  can  occur 
between  clinic  visits  and  this  can  be  reflected  as 
a  consistent  deterioration  in  some.  This  should 
be  kept  in  mind  when  interpreting  self-recorded 
peak  expiratory  flow  measurements.  Re-evalu- 
ation at  the  third  visit  following  the  retraining 
effect  of  the  second  visit  on  peak  expiratory 
flow  technique  appears  to  reduce  inaccuracies. 
It  is  believed  that  peak  expiratory  flow  tech- 
nique should  be  reevaluated  at  each  clinic  visit. 

Development  and  Validation  of  the  Mini 
Asthma  Quality  of  Life  Questionnaire — Ju- 
niper EF,  Guyatt  GH,  Cox  FM,  Ferrie  PJ,  King 
DR.  Eur  Respir  J  1999  Jul;14(l):32-38. 

The  32-item  Asthma  Quality  of  Life  Question- 
naire (AQLQ)  has  shown  good  responsiveness, 
reliability  and  construct  validity;  properties  that 
are  essential  for  use  in  clinical  trials,  clinical 
practice  and  surveys.  However,  to  meet  the  needs 
of  large  clinical  trials  and  long-term  monitor- 
ing, where  efficiency  may  take  precedent  over 
precision  of  measurement,  the  15-itein  self-ad- 
ministered MiniAQLQ  has  been  developed.  The 


1426 


Respiratory  Care  •  December  1999  Vol  44  No  12 


ACCURAa.  SAFETY. 
CONVENIENCE 

ITS  SHNMIID  mOCEDUIL 


When  obtaining  an  arterial  blood  gas  sample,  no  three  factors  are 

more  important.  Which  is  why  Hudson  RCI's  line  of  blood  gas 
,  kits  offer  features  that  allow  you  to  achieve  superior  levels  of  each. 

The  patented,  balanced  heparin  formula  establishes  an  improved  standard  of 
accuracy  in  arterial  blood  gas  analysis,  so  you  can  reliably  determine 
the  patient's  condition.  As  for  safety,  the  patented  Safeguard^M  needle 
protection  device  creates  an  additional  measure  of  security  for  the        ^ 
caregiver,  without  compromising  clinical  technique.  Finally,  the 
f      triple-function  syringe  design  allows  the  caregiver  to  obtain  an 

arterial  sample  via  any  of  the  three  primary  collection  methods  (quick  fill  pre-set,  aspiration  and 

*  pulsation),  for  exceptional  product  versatility  and  convenience.  Which  just  goes  to  show  you  at  Hudson  RCI, 

*  excellence  is  standard  procedure  too.  To  learn  more  about  Hudson  RCI's  blood  gas  kits,  call  (800)  848-3766. 


Circle  108  on  product  info  card  -  ^  — — &  HUDSON  RCI' 

Visit  Booths  520,  522  in  Las  Vegas  BreaMiig,  madeeasieif 

Distnhuted by  Huttson  RCI,  27711  Diaz  Road,  P.O.  Box  9020.  Teniecula,  CA  92589-9020  USA 

Tel:  800-84S-.V66   909-676-5611   Fax:909-676-1578 

©1999.  Hudson  RCI 


l*=z 


A  Continuing  Education  ProgrHm 
of  the  American  Association 
for  Resi>irator>'Carc 


Continuing  Education  Credit 
All  in  the  Convenience  of  Your  Facility. 
No  Planes.  No  Long  Lines.  No  Hotel  Rooms 


Resplratoiy  Therapists  Earn  i  Hour  of  CE  Credit  for  Each  Program 
Nurses  Earn  i.a  Hours  of  CE  Credit  for  Each  Program 


Professor's  Rounds  topics  O: 

just  what  your  staff  ordert 

Each  program  has  been  carejm 

selected  from  the  suggestio 

participants  provided  afi 

previous  programs.  Yourst 

will  learn  about  the  "hot  topU 

presented  by  experts  on  eo 

subject.  All  in  the  convenier 

of  your  oumfacili 

And,  your  staff  will  earn  i 

continuing  education  cre^ 

they  need  as  required: 

licensure  and  regulate 

requiremen 


Eight  Hot  Topics 


Prograin  #i 

Pulmonary  Rehabilitation:  What  You  Need  to  Know 

Live  Videoconference  -  March  7, 11:30  a.m.-l:oo  p.m.  Central  Time 
Teleconference  with  Videotape  -April  4, 11:30  a.m.-i2:oo  Noon  Central  Time 
Presenters:  Julien  M.  Roy,  BA,  RRT,  FAACVPR,  and  Richard  D.  Branson,  BA,  RRT 
What  constitutes  a  sound  pulmonary  rehabilitation  program?  How  do  you  go  about 
setting  up  a  rehab  program?  What's  the  role  of  assessment  in  developing  an  exercise 
prescription  for  the  rehab  of  your  patients?  What  are  the  issues  surrounding 
reimbursement  and  what  does  the  future  hold?  Learn  the  answers  to  these  questions 
and  gain  an  appreciation  for  the  importance  of  pulmonary  rehabilitation  to  your 
facility  and  your  patients. 

Program  #3 

Drugs,  Medications,  and  Delivery  Devices  of 

Importance  in  Respiratory  Care 

Live  Videoconference  -  April  25, 11:30  a.m.-i:oo  p.m.  Central  Time 
Teleconference  with  Videotape  -  May  16, 11:30  a.m.-i2:oo  Noon  Central  Time 
Presenters:  James  B.  Fink,  MS,  RRT,  FAARC  and  David  J.  Pierson,  MD,  PAARC 
Aerosol  therapy  is  delivered  to  nearly  80%  of  respiratory  patients.  There  are  a 
number  of  new  medications  in  development  for  both  local  and  systemic 
administration  to  those  patients.  Which  device  to  use,  how  to  negotiate  care 
plans,  and  how  to  educate  both  patients  and  caregivers  are  all  topics  that  will  be 
discussed.  Perhaps  of  critical  importance  is  getting  the  most  medication  delivered 
to  the  patient's  lungs,  which  leads  to  a  discussion  of  selecting  the  correct  delivery 
device. 

Program  #5 

Pediatric  Ventilation:  Kids  Are  Different 

Live  Videoconference  -  July  25, 11:30  a.m.-i:oo  p.m.  Central  Time 
Teleconference  with  Videotape  -  August  15, 11 :30  a.m.-i2:oo  Noon  Central  Time 
Presenters:  Mark  Heulitt,  MD,  FAAP,  FCCP  and  Richard  D.  Branson,  BA,  RRT 
There  are  significant  differences  in  the  anatomy  and  physiology  of  the  respiratory 
systems  between  adults  and  children,  posing  problems  for  the  practitioner  attempting 
to  mechanically  ventilate  a  pediatric  patient.  Once  the  process  is  underway,  the 
capabilities  of  the  available  mechanical  ventilators  and  how  they  affect  children 
pose  additional  problems.  Children  are  so  different,  you  need  to  stop  and  reassess 
actions  you  would  normally  take  with  an  adult  patient. 


Program  #7 

Managing  Asthma:  An  Update 

Live  Videoconference  -  September  ig,  11:30  a.m.-i:oo  p.m.  Central  Time 
Teleconference  with  Videotape  -  October  17, 11:30  a.m.-i2:oo  Noon  Central  Time 
Presenters:  PattiJoyner,  RRT,  CCM  and  Mari  Jones,  MSN,  RN,  FNP,  RRT 
Asthma  management  is  a  hot  topic  for  discussion.  Everyone  wants  to  implement  a 
program  at  his  or  her  facility.  What  will  make  a  program  work,  and  how  do  you  know 
if  it's  successful?  This  program  will  provide  you  with  the  information  you  have  been 
lookinf,  for  in  order  to  implement  a  program  and  determine  how  successful  the 
progra  r'l  rrally  is.  You  will  be  given  guidance  on  how  to  analyze  outcomes  measures 
from  a  su    ossful  program. 


V 


Program  #2 

Pediatric  Asthma  in  the  ER 

Live  Videoconference  -  March  28, 11:30  a.m.-i:oop.m.  Central  Time 
Teleconference  with  Videotape  -  April  18, 11:30  a.m.-l2:oo  Noon  Central  Time 
Presenters:  Timothy  R.  Meyers,  BS,  RRT  and  Thomas  J.  Kallstrom,  RRT,  FAARC 
The  prevalence  of  pediatric  asthma  has  increased  dramatically  in  the  last  few  years. 
The  National  Asthma  Education  and  Prevention  Program  has  provided  guidelines  for 
management  of  pediatric  asthma.  This  program  will  discu,ss  these  issues  as  well  as  the 
role  of  care  paths  in  the  management  of  the  disease.  Additionally,  there  have  been 
some  significant  advances  in  coping  with  pediatric  asthma  in  the  ER. 


Program  #4 

Cost- Effective  Respiratory  Care:  You've  Got  to  Change 

Live  Videoconference  -  May  23, 11:30  a.m.-i:oop.m.  Central  Time 
Teleconference  with  Videotape  -  June  20, 11:30  a.m.-i2:oo  Noon  Central  Time 
Presenters:  Kevin  L.  Shrake,  MA,  RRT,  FACHE,  FAAMA,  FAARC  and  Sam  P. 
Giordano,  MBA,  RRT,  FAARC 

Practitioners  frequently  confuse  the  implementation  of  protocol  treatment  and  case 
management.  Both  programs,  if  successfully  implemented,  can  lead  to  cost  savings. 
The  problem  most  practitioners  face  is  how  to  identify  where  costs  are  avoided  and 
resources  are  conserved.  Perhaps  most  critical  is  ensuring  that  the  correct  care  is 
delivered  at  the  proper  time.  The  health  care  practitioner  is  key  to  the  ultimate  success 
of  these  programs. 


Program  #6 

What  Matters  in  Respiratory  Monitoring: 

What  Goes  and  What  Stays 

Live  Videoconference  -  August  22, 11:30  a.m.-i:oo  p.m.  Central  Time 
Teleconference  with  Videotape  -  September  26, 11:30  a.m.-i2:oo  Noon  Central  Time 
Presenters:  DeanR.  Hess,  PhD,  RRT,  FAARC  and  Richard  D.  Branson,  BA.RRT 
The  health  care  provider  has  an  array  of  monitoring  devices  available  in  managing  a 
patient.  With  all  that  technology  available,  which  device  is  appropriate?  What  about 
those  displays  on  ventilators?  The  availability  of  graphics  during  mechanical  ventilation 
can  provide  a  wealth  of  information.  When  is  it  essential?  Under  what  circumstances 
should  you  pay  close  attention  to  those  displays  in  the  assessment  of  your  patient? 

Program  #8 

Routine  Pulmonary  Function  Testing:  Doing  It  Right 

Live  Videoconference  -  November  7, 11:30  a.m.-i.oo  p.m.  (Antral  Time 
Teleconference  with  Videotape  -  December  5,11 :30  a.m.-i2:oo  Noon  Central  Time 
Presenters:  Carl  D.  Mottram,  BA,  RRT,  RPFTand  David  J.  Pierson,  MD,  FAARC 

Pulmonary  fiinction  testing  at  the  bedside  is  being  increasingly  utilized  as  a  diagnostic 
tool.  Is  it  always  appropriate?  How  can  you  assure  competency  of  the  person  conducting 
the  test?  How  can  you  assure  quality  assurance  outside  the  pulmonary  function 
laboratory?  This  program  will  provide  you  with  the  information  you  need  to  assure  that 
this  diagnostic  test  is  properly  conducted  outside  the  laboratory. 


Ik 


Iki 


[  Accreditation 

Respiratory  Care: 

Each  program  is  approved  for  i  hour  of  continuing  education  credit  by  Continuing  Respiratory  Care  Education  (CRCE).  Purchase  of 
videotapes  only  does  not  earn  continuing  education  credit.  Registrants  must  participate  in  the  live  program  or  the  telephone  seminar 
to  earn  continuing  education  credits. 

Nursing: 

Each  program  is  approved  for  1.2  hours  of  continuing  education  credit  by  the  Texas  Nurse  Association.  Purchase  of  videotapes 
only  does  not  earn  continuing  education  credit.  Registrants  must  participate  in  the  live  program  or  the  telephone  seminar  to  earn 
continuing  education  credits. 

f  Live  Videoconference  Requirements 

Sites  must  have  satellite  reception  capabilities  (with  moveable  dish),  video  monitor,  a  telephone,  and  an  individual  to  proctor  the 
program.  Participants  will  view  a  live  90-minute  satellite  television  broadcast  with  a  live  call-in  question-and-answer  session. 
Program  materials  for  the  live  program  include  satelHte  coordinates,  toll-free  telephone  number,  continuing  education  packet, 
attendance  log  and  reproducible  course  materials,  post-test  with  answers,  evaluation,  and  certificate  of  attendance. 


I 


Teleconference  with  Videotape  Requirements 


Sites  must  have  a  video  monitor,  a  VCR,  a  telephone  with  speaker  phone,  and  an  individual  to  proctor  the  program.  Participants 
will  receive  and  view  a  90-minute  videotape  and  then  call  a  toll-ft«e  number  for  a  live  30-minute  call-in  question-and-answer 
session.  Program  materials  for  the  telephone  session  include  the  toll-free  telephone  number,  continuing  education  packet, 
attendance  log,  videotape  and  reproducible  course  materials,  post-test  with  answers,  evaluation,  and  certificate  of  attendance. 


k 

t 


Registration 


D  Sign  Us  Up  for  Continuing  Education  in  the  Convenience  of  Our  Own  Facility 

Single  Programs:  $245  per  facility  ($215  for  AARC  Members) 

Entire  Series  of  Eight:  $i,395  per  facility-Save  $565  ($1,225  for  AARC  Members-Save  $495) 

Late  Registration  Fee:  $15  (If  registering  within  one  week  of  program) 

CALL  FOR  MULTI-FACILITY  DISCOUNT 


Payment  Enclosed     Charge  to:  D  Visa     D  MasterCard    D  Purchase  Order  (P.O.) 


dit  Card  or  P.O.  No. . 


Exp.  Date_ 


lature  (Required  for  Credit  Card  and  P.O.) 
oimt  of  Order  $ 

f 


AARC  Member  Number  _ 
(Required for  Discount) 


artment_ 
Jity 


Ship  Program  Materials  To  (No  Post  Office  Boxes): 


lress_ 


/State/Zip_ 
:phone 


Bill  To  (If  Different  From  Left): 


Name_ 
Title_ 


Department. 
Facility 


Address_ 


City/State/Zip_ 
Telephone 


Reception  Options 

(You  Must  Select  One  Only) 
D  Live  Videoconference 
n  Teleconference  with  Videotape 
n  Videotape  Only  (No  CE  Credit)* 


Check  Oie  Desired  Programs 

n  Entire  Series  of  Eight 

n*4    n#8 


•Videotapes  will  not  be  available  until  after  the  live  videoconference 
and  do  not  include  course  materials. 


AARC  Professor's  Rounds 

Phone  (972)  243-2272  -  Facsimile  (972)  484-2720  - 11030  Abies  Lane  -  Dallas,  Texas  75229-4593 


%ols  of  the  Trade 

Interested  in  the  topics  discussed  in  this  issue?  Here  are  some  resources  you  may  find  helpful. 
Check  Out  These  Resources  on  Asthma  From  the  AARC: 


Status  Asthmaticus  Simulation 

Involves  the  initial  assessment  of  a  35-year-old  man  with  a  history  of 
allergic  asthma.  Low-flow  oxygen  is  aaministered  initially,  followed  by 
bronchodilator  therapy.  As  the  simulation  progresses,  the  patient  is 
intubated  and  receives  mechanical  ventilation.  The  user  is  required  to 
make  initial  settings  and  adjustments  according  to  ABG  results  and 
patient  response.  Also  included  in  the  simulation  is  a  switch  to  IMV 
mode,  sedation,  and  eventual  extubation  and  placement  on  a  40 
percent  aerosol  mask.  CAI  Software  (Requires  Windows*  3.1  or 
Higher). 
Item  SP1 2  $65.00 

Bronchodilators  I:  Sympathomimetic  Amines 

Understand  the  results  of  stimulating  the  autonomic  nervous  system 
and  the  use  of  sympathomimetic  drugs  to  accomplish  bronchodilation. 
Exposes  you  to  oasic  aspects  of  adrenergic  bronchodilators  and  the 

?iatient  situations  for  which  they  are  indicated.  Individual 
ndependent  Study  Package  (IISP). 
Item  CS14  $12.00  (nonmembers  $16.00) 

Bronchodilators  II:  Anti-Cholinergics  and  Xanthines 

Identifies  the  three  categories  of  drugs  that  promote  bronchodilation 
and  the  mechanism  of  action  for  each.  This  package  also  provides 
examples  of  drugs  in  each  category  Clinical  situations  are  presented 


with  methods  of  bronchodilation  and  rationale  for  method  selected. 
Individual  Independent  Study  Package  (IISP). 
Item  CS15  $12.00  (nonmembers  $16.00) 

Asthma  Drugs  and  Medications:  What's  Right  and  What's 
Wrong 

Reviews  the  pharmacology  section  of  the  revised  NAEPP  Guidelines. 
Additionally,  the  potential  hazards  and  undesirable  side  effects  of 
commonly  prescribed  medications  will  be  discussed,  with  alternative 
treatment  regimens  suggested.  Featuring  William  Luskin,  MD,  and 
David  J.  Pierson,  MD.  80-min.  videotape. 

Item  VC81  $49.95  (nonmembers  $99.00) 

Asthma  Disease  Management:  Using  the  Revised 
NAEPP  Guidelines  in  Practice 

Learn  the  four  essential  components  of  the  NAEPP  Guidelines  that 
are  essential  to  asthma  disease  management,  and  how  these 
components  are  incorporated  into  a  comprehensive  asthma 
management  program  in  the  work  setting^  from  the  hospital  to  home 
care.  FeaturingThomasJ.  Kallstrom,  RRT,  Gretchen  Lawrence,  BA, 
RRT,  and  SarnP.  Giordano,  MBA,  RRT.  80-min.  videotape. 
Item  VC74  $49.95  (nonmembers  $99.00) 


Here  is  How  You  Can  Learn  More  About 
Diagnostics: 

Diagnostic  Training  and  Competence  Assessment 
Manual  for  Pulmonary  and  Noninvasive  Cardiology 

The  new  Diagnostic  Training  and  Competence  Assessment  Manual  for 
Pulmonary  and  Noninvasive  Cardiology  on  CD-ROM  is  now  available. 
Pulmonary  Diagnostics  Section  features:  quality  control,  diffusing 
capacity,  whole  body  plethysmography,  indirect  calorimetry,  arterial 
blood  gas  sampling,  bronchoscopy,  spirometry,  static  lung  volumes, 
bronchial  provocation  testing,  pulse  oximetry,  venipuncture, 
technologist-driven  protocols.  Noninvasive  Cardiology  Section 
features:  electrocardiography,  cardiopulmonary  stress  testing, 
transtelephonic  event  monitoring,  transtelephonic  pacemaker 
evaluation,  graded  exercise  testing,  ambulatory  electrocardiography, 
high  resolution  signal-average  ECG.  Requirements:  486  or  Pentium 
class  computer  with  Windows  3.1,  Windows  95  or  higher  and  8  MB  of 
available  hard  drive  space  and  a  CD  ROM  drive. 
Item  PA99  $267.00  ($289.00  nonmembers) 

Uniform  Reporting  Manual  for  Diagnostic  Services 

This  manual  identifies  diagnostic  procedures  commonly  performed 
within  sleep,  pulmonary,  blood  gas,  and  noninvasive  cardiology 
laboratories  and  time  standards  for  their  performance.  It  is  a  tool  to 
determine  productivity,  track  trends  in  the  utilization  of  services, 
assist  in  determining  personnel  requirements,  and  measure  demand  for 
and  intensity  of  service.  It  also  provides  a  foundation  for 
benchmarking  efficiency  indicators  within  the  industry.  188  pages. 
ITEM  PM88  $99.00  ($135.00  nonmembers) 


Helpful  Tools  for  Arterial  Blood  Gas  Analysis: 

Blood  Gas  and  Related  Measurements:  Laboratory 
Versus  Bedside  Devices 

Presents  the  various  means  of  obtaining  blood  gas  information  using 
invasive  and  noninvasive  devices,  the  need  for  such  devices,  and  when 
they  should  be  used.  Featuring  Barry  R.  Shapiro,  MD,  and  Richard  D. 
Branson,  BS,  RRT.  80-min.  videotape. 
Item  VC44  $49.95  ($99.00  nonmembers) 

Sources  of  Error  in  the  Determination  of  Blood  Gas 
Values  and  pH 

Familiarizes  you  with  the  errors  that  may  occur  in  the  analysis  of  blood 
gases  and  pH.  These  are  often  the  most  important  laboratory  data 
used  in  the  diagnosis  and  treatment  of  pulmonary  disease,  and  errors 
in  these  values  can  result  in  deleterious  effects  on  patient  care. 
Individual  Independent  Study  Package  (IISP). 
Item  PE7  $12.00  ($16.00  nonmembers) 

Temperature  Adjustment  of  Blood  Gases  and  pH 

Teaches  you  the  effects  of  abnormal  body  temperature  on  blood  gas 
and  pH  values.  Blood  gas  values  and  pH  are  determined  at  37  degrees 
Celsius,  and  this  package  teaches  you  how  to  adjust  these  values. 
Individual  Independent  Study  Package  (IISP). 
Item  PE8  $12.00  ($16.00  nonmembers) 

Arterial  Blood  Gas  Interpretation 

Teaches  ABG  interpretation  for  administering  therapy  in  a 
knowledgeable  manner.  Describes  a  systematic  method  that  allows  yoi 
to  correctly  classify  the  acid-base  dysfunction  and  to  relate  the 
diagnosis  concisely  and  coherently  Individual  Independent  Study 
Package  (IISP). 
Item  PE 10  $12.00  ($16.00  nonmembers) 


See  these  items  for  more  information  on  pulmonary  rehabilitation: 


How  to  Implement  a  Pulmonary  Rehabilitation  Program 

Describes  all  the  steps  and  procedures  necessary  for  the  implementa- 
tion of  an  effective  pulmonary  rehabilitation  program.  Presents  ways 
to  ensure  all  requirements  are  followed.  Very  comprehensive.  Byjulien 
M.  Roy,  BA,  RRT.  Audiotape. 

Item  PAD75  $15.00  ($20.00  nonmembers) 

A  Business  and  Marketing  Plan  for  Pulmonary 
Rehabilitation 

Explains  the  business  side  of  a  pulmonary  rehabilitation  program. 
Describes  how  to  write  a  business  plan  and  now  to  market  it.  By  Trina 
M.  Limberg,  BS,  RRT.  Audiotape. 

Item  PAD76  $1 5.00  ($20.00  nonmembers) 
Outcomes  for  Pulmonary  Rehabilitation 

Details  all  the  requirements  necessary  to  set  up  a  basic  outcomes 
measurement  program  for  a  pulmonary  rehabilitation  program.  By 
Trina  M.  Limberg,  BS,  RRT.  Audiotape. 

Item  PAD78  $15.00  ($20.00  nonmembers) 

Pulmonary  Rehabilitation  Across  the  Continuum  of  Care 

Learn  the  steps  necessary  for  implementation  of  a  sound  pulmonary 
rehabilitation  program  and  methods  ensuring  requirements  of 
intermediaries  are  met.  Necessary  documentation  will  be  discussed  to 
assure  reimbursement.  Featuring  Julien  M.  Roy,  BA,  RRT,  and  Richard 
D.  Branson,  BS,  RRT.   8o-min.  videotape. 

Item  VC83  $49.95  ($99.00  nonmembers) 
Pulmonary  Rehabilitation 

Learn  the  components  of  a  comprehensive  pulmonary  rehabilitation 
program,  how  to  select  appropriate  candidates,  and  how  to  identify  and 
set  both  short-  and  long-term  patient  goals.  Also  covers  assessment  of  a 
patient's  progress  and  follow-up.  Featuring  Barry  M.  Make,  MD,  and 
David  J.  Pierson,  MD.  8o-min.  videotape. 

Item  VC24  $49.95  ($99.00  nonmembers) 

Keep  Your  Mechanical  Ventilation  Skills  Up-to-Date 
with  These  Tools:  Unconventional  Methods  for  Adult 
Oxygenation  and  Ventilation  Support 

Provides  an  overview  of  new  and  experimental  techniques  for  adult 
oxygenation  and  ventilation  support.  Discusses  the  techniques, 
theoretical  rationales,  methods  of  application,  and  experimental 
evidence  of  the  effectiveness  of  these  unconventional  methods. 
Featuringjames  K.  Stoller,  MD,  and  David  J.  Pierson,  MD.   8o-min. 
videotape. 

Item  VC36  $49.95  ($99.00  nonmembers) 


Noninvasive  Mechanical  Ventilation:  Its  Role  in  Acute 
and  Chronic  Respiratory  Failure 

Reviews  the  history  of  noninvasive  ventilation,  describes  modalities 
currently  available,  and  discusses  the  pros  and  cons  of  each.  Results  of 
studies  on  acute  and  chronic  respiratory  failure  are  reviewed,  and 
acceptable  indications  for  use  of  noninvasive  ventilation  are  described. 
Considerations  for  selecting  appropriate  patients,  and  techniques  of 
initiation  and  monitoring  of  noninvasive  ventilation  are  also  discussed. 
Featuring  Nicholas  S.  Hill,  MD,  and  Richard  D.  Branson,  BS,  RRT. 
8o-min.  videotape. 

Item  VC55  $49.95  ($99.00  nonmembers) 
Managing  the  Ventilator:  What  and  When 

Reviews  initial  ventilator  setup  and  selection  of  appropriate  settings. 
Covers  monitoring  the  patient,  responding  to  clinical  data  with 
appropriate  adjustments,  the  techniques  for  effective  secretion 
clearance,  infection  control,  and  recognizing  who  is  ready  to  wean. 
Featuring  Dean  R.  Hess,  PhD,  RRT,  and  Richard  D.  Branson,  BS,  RRT. 
8o-min.  videotape. 

Item  VC62  $49.95  ($99.00  nonmembers) 

Theory  and  Application  of  Neonatal  Ventilation: 
What,  When,  and  Why 

Evaluates  neonates  in  need  of  ventilation,  assessment  and  ventilator 
monitoring,  and  how  to  recognize  the  neonate  in  respiratory  failure. 
Also  provided  are  instructions  for  minimizing  iatrogenic  lung  damage, 
with  a  summary  application  of  the  new  modes  of  ventilation  and 
respiratory  support  in  neonates.  Featuring  Robert  L.  Chatburn,  RRT, 
and  Richard  D.  Branson,  BS,  RRT.   8o-min.  videotape. 

Item  VC65  $49.95  ($99.00  nonmembers) 
Pressure  Support  During  Mechanical  Ventilation 

Defines  pressure  support,  its  differences,  and  how  it  is  used  during 
ventilator  weaning.  Also  presents  clinical  situations  and  how  to 
determine  appropriate  levels  with  each  new  patient.  Featuring  Neil  R. 
Maclntyre,  MD,  and  David  J  .  Pierson,  MD.  8o-min.  videotape. 

Item  VC21  $49.95  ($99.00  nonmembers) 

The  New  Ventilator  Management:  Permissive 
Hypercapnia  and  Other  Variations  on  Conventional 
Mechanical  Ventilation 

Outlines  techniques  and  theories,  including  pressure-limited 
ventilation,  reduced  peak  pressure,  permissive  hypercapnia,  weaning 
and  imposed  work  of  breathing,  and  the  next  generation  of  ventilators. 
Featuring  Neil  R.  Maclntyre,  MD,  and  Richard  D.  Branson,  BS,  RRT. 

Item  VC46  $49.95  ($99.00  nonmembers) 


Order  Form 

□  Check  Enclosed  □  Visa 


Method  of  Payment:  □  Purchase  Order: 

Credt  Card  Number Expiration  Date  _ 

Signature  (Required  for  Credit  Cards  and  Purchase  Orders) 

AARC  Member  Number Telephone  Number_ 

Name Institution 


□  MasterCard 


Street  Address 
Quantity 

ltem# 

Ciry/Srare/Zip 
Description 

Price  Ea 

Total 

Shipping  Rates 

International  orders 
Order  Total 

require  an  additional  $25. 
UPS  Reg.        AK.HI.PR 

Order  Total 

UPS  Reg. 

AK.HI.PR 
$25.00 

$80.01  to  $100 

$  9.25 

$100.01  to  $150 
$150.01  to  $200 
$250.01  to  $300 
$300.01  $400 

$10.25 
$12.25 
$16.25 
$18.25 

$30.75 
$33.00 
$44.00 
$58.50 

$15  or  less 

$  4.25 

$12.25 

$15.01  to  $25 

$   5.25 

$14.50 

$25.01  to  $40 

$  6.25 

$17.00 

$40.01  to  $60 

$  7.25 

$19.25 

$60.01  to  $80 

$  8.25 

$21.50 

$400  or  more 

$20.25 

$64.50 

Item  Subtotal . 

Shipping 

Subtotal 


Texas  Sales  Tax . 
Total 


Call  (972)  243-2272  or  Fax  to  (972)  484-2720  with  MasterCard,  Visa,  or  Purchase  Order  Number 
Other  Products  are  Available  Online  at  www.aarc.org/professional_resources/keys/ 

American  Association  for  Respiratory  Care  11030  Abies  Lane,  Dallas,  TX  75229 

Valid  AARC  Member  Number  Required  (or  Member  Prices.  NonExempt  Texas  Customers  Only,  Please  Add  8.25%  Sales  Tax  (Charged  on  Product  Cost  and  Shipping  Charges). 

Visit  www.aarc.ora 


Abstracts 


MiniAQLQ  was  tested  in  a  9-week  observa- 
tional study  of  40  adults  with  syinptomatic 
asthma.  Patients  completed  the  MiniAQLQ,  the 
AQLQ,  the  Short  Form  (SF)-36.  the  Asthma 
Control  Questionnaire  and  spirometry  at  base- 
line. 1 ,  5  and  9  weeks.  In  patients  whose  asthma 
was  stable  between  clinic  visits,  reliability  was 
very  acceptable  for  the  MiniAQLQ  (intraclass 
correlation  coefficient  (ICC)=0.83).  but  not 
quite  as  good  as  for  the  AQLQ  (ICC=0.95). 
Similarly,  responsiveness  in  the  MiniAQLQ 
(p=0.0007)  was  good  but  not  quite  so  good  as 
for  the  AQLQ  (p<0.0001).  Construct  validity 
(correlation  with  other  indices  of  health  status) 
was  strong  for  both  the  MiniAQLQ  and  the 
AQLQ.  Criterion  validity  showed  thai  there  was 
no  bias  between  the  instruments  (p=0.61)  and 
the  correlation  between  them  was  high  (r=0.90). 
The  Mini  Asthma  Quality  of  Life  Question- 
naire has  good  measurement  properties  but  they 
are  not  quite  as  strong  as  those  of  the  original 
Asthma  Quality  of  Life  Questionnaire.  The 
choice  of  questionnaire  should  depend  on  the 
task  at  hand. 

Quality  of  Life  in  Elderly  Subjects  with  a 
Diagnostic  Label  of  Asthma  from  General 
Practice  Registers— Dyer  CA,  Hill  SL,  Stock- 
ley  RA,  Sinclair  AJ.  Eur  Respir  J  1999  Jul; 

14(l):39-45. 

The  aim  of  this  study  was  to  assess  health- 
related  quality  of  life  (QoL)  in  elderly  subjects 
with  a  diagnostic  label  of  asthma  from  a  gen- 
eral practice  population,  and  to  determine  the 
main  contributory  factors.  Sixty  people  aged  a 
70  yrs  with  a  primary  care  diagnostic  label  of 
asthma,  and  43  control  subjects  were  recruited. 
Assessment  of  bronchodilator  response,  and  oral 
steroid  trials  were  conducted  where  possible. 
The  main  outcome  measures  were  QoL  scores 
for  the  Short  Form  (SF)-36  and  the  St  George's 
Respiratory  Questionnaire  (SGRQ).  In  the 
asthma  group,  29  subjects  demonstrated  a  sig- 
nificant airway  response  to  bronchodilators  or 
steroids.  Mean  SF-36  scores  were  significantly 
worse  in  the  total  asthma  group  for  components 
of  physical  function,  physical  role  limitation, 
and  general  health,  although  psychological 
scores  were  similar.  QoL  remained  worse  than 
controls  in  those  subjects  with  a  significant  bron- 
chodilator response.  Dyspnoea  and  depression 
accounted  for  61  %  of  the  variance  in  the  SGRQ, 
but  forced  expiratory  volume  in  one  .second  was 
not  an  independent  variable.  Quality  of  life  is 
impaired  in  elderly  people  with  a  diagnosis  of 
a.sthma,  including  those  with  demonstrable  air- 
way variability.  Many  older  subjects  with 
asthma  note  a  variety  of  symptoms,  highlight- 
ing the  need  for  further  research  into  the  ade- 
quacy and  efficacy  of  their  treatment. 

A  Comparison  of  a  New  Transtelephonic  Por- 
table Spirometer  with  a  Laboratory  Spirom- 
eter— Izbicki  G,  Abboud  S,  Jordan  P,  Perru- 


choud  AP,  Bolliger  CT.  Eur  Respir  J  1999  Jul; 
14(1):209-213. 

The  Spirophone  is  a  new,  portable  transtele- 
phonic spirometer  which  records  the  slow  and 
the  forced  expiratory  vital  capacity  tests.  Data 
can  be  transmitted  via  the  telephone  to  a  remote 
receiving  centre,  where  a  volume-time  curve 
and  the  flow-volume  curve  are  displayed  on 
screen  in  real  time.  The  aim  of  this  study  was  to 
compare  the  newly  developed  transtelephonic 
spirometer,  with  a  laboratory  spirometer  accord- 
ing to  the  American  Thoracic  Society  (ATS) 
testing  guidelines.  Spirometry  indices  (slow  vi- 
tal capacity  (SVC),  forced  vital  capacity  (FVC), 
forced  expiratory  volume  in  one  second  (FEV , ). 
peak  expiratory  flow  (PEF),  forced  expiratory 
flow  at  25,  50  and  75%  of  FVC  (FEF,,,  FEF,„, 
and  FEF,,,  respectively))  were  measured  from 
the  SVC  and  the  FVC  tests  in  45  subjects  (30 
patients,  15  healthy  volunteers)  according  to 
the  ATS  standards.  The  data  obtained  with  the 
laboratory  system  were  compared  to  those  from 
the  Spirophone.  The  Spirophone  measurements 
of  SVC,  FVC,  FEV,,  PEF,  FEF,,,  FEE,,,  and 
FEF,,  correlated  closely  (r=0.9 1-0.98)  to  those 
from  the  laboratory  system,  whereas  FEF^,, 
FEF50  and  FEF75  were  significantly  higher  with 
the  Spirophone.  It  is  concluded  that  the  Spiro- 
phone is  comparable  to  the  standard  spirometry 
for  home  monitoring  of  slow  vital  capacity, 
forced  vital  capacity,  forced  expiratory  volume 
in  one  second  and  peak  expiratory  flow.  The 
validity  of  the  manoeuvre  can  be  assessed  on 
screen  in  real  time. 

Accuracy  of  the  i-STAT  Bedside  Blood  Gas 
Analyser — Sediame  S,  Zerah-Lancner  F, 
d'Ortho  MP.  Adnot  S,  Harf  A.  Eur  Respir  J 

1999  Jul;l4(l):214-2I7. 

The  performance  of  the  i-STAT  portable  clin- 
ical analyser  for  measuring  blood  gases  and  pH 
was  evaluated  with  reference  to  a  conventional 
blood  gas  analyser  (ABL520  Radiometer).  Nine- 
ty-two samples  from  the  routine  blood  gas  anal- 
ysis laboratory  were  chosen  according  to  a  wide 
distribution  of  partial  pressure  of  carbon  diox- 
ide (Paco,)-  partial  pressure  oxygen  (Pao,)  and 
pH  and  then  analysed.  All  measurements  were 
performed  in  duplicate  by  trained  technicians 
from  the  central  hospital  laboratory.  Differences 
between  duplicate  measurements  were  com- 
puted for  Paco,:  (1-2  versus  0.4%),  P^o,  (1.7 
versus  1.1%)  and  pH  (0.06  versus  0.02%).  for 
the  i-STAT  and  ABL520,  respectively.  pH  and 
Pacc),  values  measured  with  the  i-STAT  were 
very  close  to  tho.se  obtained  with  the  ABL52(). 
the  difference  (mean±SD)  being  0.006±0.018 
and  -0.1 3 ±0.17  kPa,  respectively.  Statistical 
analysis  .showed  that  the  differences  between 
analysers  did  not  depend  on  values  of  pH  or 
Pucot  The  performance  of  the  analy.sers  de- 
pended on  the  level  of  POj.  Below  15  kPa 
(n=48),  the  two  systems  gave  nearly  identical 


values,  the  mean  difference  was  0.01  ±0.37  kPa. 
Between  16  and  55  kPa  (n=44),  there  was  a 
systematic  but  small  (-0.69±0.67  kPa)  under- 
estimation of  Pao,  measured  with  the  i-STAT 
(p<10").  In  conclusion,  this  study  shows  that 
blood  gas  analysis  using  the  i-STAT  portable 
device  is  comparable  with  that  performed  by  a 
conventional  laboratory  blood  gas  analyser. 

Lung  Volume  Reduction  Surgery  (LVRS)  for 
Chronic  Obstructive  Pulmonary  Disease 
(COPD)  with  Underlying  Severe  Emphyse- 
ma— Young  J,  Fry-Smith  A,  Hyde  C.  Thorax 
1999  Sep;54(9):779-789. 

BACKGROUND:  Lung  volume  reduction  sur- 
gery (LVRS)  has  recently  re-emerged  as  a  sur- 
gical option  for  the  treatment  of  end  stage 
chronic  obstructive  pulmonary  disease  (COPD) 
due  to  underlying  severe  emphysema.  Advo- 
cates of  LVRS  claim  that  it  represents  a  signif- 
icant breakthrough  in  the  management  of  this 
challenging  group  of  patients  while  sceptics 
point  to  uncertainty  about  the  effectiveness  of 
the  operation.  METHODS:  A  systematic  review 
was  conducted  of  the  evidence  on  the  effects  of 
LVRS  in  patients  with  end  stage  COPD  sec- 
ondary to  severe  emphysema.  RESULTS:  The 
most  rigorous  evidence  on  the  effectiveness  of 
LVRS  came  from  case  series.  Seventy  five  po- 
tentially relevant  studies  were  identified  and  19 
individual  .series  met  the  methodological  crite- 
ria for  inclusion.  The  pattern  of  results  was  con- 
sistent across  individual  studies  despite  a  sig- 
nificant degree  of  clinical  heterogeneity. 
Significant  short  term  benefits  occurred  across 
a  range  of  outcomes  which  appeared  to  con- 
tinue into  the  longer  term.  Physiological  im- 
provements were  matched  by  functional  and 
subjective  improvements.  Early  mortality  rates 
were  low  and  late  mortality  rates  compared 
favourably  with  tho.se  of  the  general  COPD  pop- 
ulation. However,  the  entire  research  base  for 
the  intervention  is  subject  to  the  limitations  of 
study  designs  without  parallel  control  groups. 
CONCLUSIONS:  LVRS  appears  to  represent  a 
promising  option  in  the  management  of  patients 
with  severe  end  stage  emphysema.  However, 
until  the  results  of  ongoing  clinical  trials  are 
available,  the  considerable  uncertainty  that  ex- 
ists around  the  effectiveness  and  cost  effective- 
ness of  the  procedure  will  remain. 

The  Open  Circuit  Nitrogen  Washout  Tech- 
nique for  Measuring  the  Lung  Volume  in 
Infants:  Methodological  Aspects — Morris 
MG.  Thorax  1999  Sep;54(9):790-795. 

BACKGROUND:  Lung  volume  measurement 
by  nitrogen  washout  is  widely  used  in  infants, 
though  a  lack  of  accuracy  and  changes  of  cal- 
ibration over  time  have  been  reported.  The  po- 
tential sources  of  error  were  explored  in  order 
to  increase  the  accuracy  and  reliability  of  the 
technique.  METHODS:  A  commercial  system 


1432 


Respiratory  Care  •  December  1999  Vol  44  No  12 


for  nitrogen  washout  and  a  0.5  litre  calibrating 
syringe  as  a  lung  model  were  used  to  perform 
over  2000  in  vitro  washouts,  including  simu- 
lated rapid  breathing,  shallow  breathing,  peri- 
odic breathing,  sighs,  and  brief  apnoeas.  A  con- 
stant 10  L/min  bias  flow  of  oxygen  and  extended 
equipment  warming  times  were  employed.  A 
collapsible  breathing  bag  was  incorporated  into 
the  washout  circuit.  Following  a  single  two  point 
calibration,  known  air  volumes  from  42  mL  to 
492  mL  were  measured  by  nitrogen  washout 
over  a  14  hour  period.  The  flow  waveform  in 
the  nitrogen  mixing  chamber  during  a  washout 
in  vitro,  with  and  without  the  breathing  bag  in 
the  circuit,  was  also  studied.  RESULTS:  The 
mean  coefficient  of  variation  of  all  volumes 
was  0.66%.  The  mean  difference  between  mea- 
sured and  known  volumes  was  0.30  mL  (95% 
confidence  interval  (CI)  -0.18  to  0.79).  This 
difference  was  not  statistically  significant  (p  = 
0.22).  The  mean  percentage  error  was  -0.1% 
(range  -0.47%  to  0.46%).  Nitrogen  calibration 
remained  stable  for  14  hours.  Without  the  breath- 
ing bag  flow  transients  were  frequent  in  the 
mixing  chamber  during  in  vitro  washout.  CON- 
CLUSIONS: This  technique  increa.ses  the  ac- 
curacy in  vitro  and  the  precision  in  vivo  of 
volume  measurement  by  nitrogen  washout. 
Sources  of  potential  errors  including  baseline 
drifting  and  inadequate  equipment  warming 
times  were  identified.  The  breathing  bag  acted 
as  a  buffer  reservoir,  preventing  large  swings  in 
flows  within  the  nitrogen  mixing  chamber  dur- 
ing washouts,  and  should  be  an  integral  com- 
ponent of  the  nitrogen  washout  circuit. 

Pressure-Limited  Ventilation  of  Infants  with 
Low-Compliance  Lungs:  The  Efficacy  of  an 
Adult  Circle  System  Versus  Two  Free- 
standing Intensive  Care  Unit  Ventilator  Sys- 
tems Using  an  in  Vitro  Model — Stevenson 
GW.  Horn  B,  Tobin  M,  Chen  EH,  Sautel  M. 
Hall  SC, Cote CJ.  Anesth  Analg  1 999  Sep;89(.3): 
638-641. 

We  compared  the  efficacy  of  a  Drager  Narkomed 
GS  (North  American  Drager.  Telford,  PA) 
equipped  with  an  adult  circle  system  with  two 
free-standing  infant  ventilator  systems  (Servo 
300;  Siemens  Medical  Systems,  Danvers,  MA 
and  Babylog  8000;  North  American  Drager)  to 
deliver  minute  ventilation  (V^)  using  pressure- 
limited  ventilation  to  a  te.st  lung  set  to  low  com- 
pliance. To  simulate  a  wide  variety  of  potential 
patterns  of  ventilation,  Vp  was  measured  at  peak 
inspiratory  pressures  (PIP)  of  20,  30. 40,  and  50 
cm  HjO  and  at  respiratory  rates  (RR)  of  20,  30, 
40,  and  50  breath.s/min.  Each  measurement  was 
made  three  times;  the  average  was  used  for  data 
analysis  using  the  multiple  regression  technique. 
Delivered  V^  was  positively  correlated  with  both 
PIP  (p  =  0.001)  and  RR  (p  =  0.001).  Only 
minimal  differences  in  Vp  were  observed  be- 
tween the  circle  and  the  two  free-standing  sys- 
tems. At  lower  RR  and  PIP.  the  Babylog  8000 


Circle  111  on  product  Info  card 


.sy.stem  delivered  slightly  higher  V^  than  the 
circle  system,  whereas  at  higher  RR  and  PIP. 
the  Babylog  8000  delivered  slightly  lower  Vp 
than  the  circle  system;  these  differences  in  Vg 
were  not  statistically  significant  (p  =  0.45).  The 
Servo  300  delivered  slightly  higher  Vp  than  the 
circle  system  in  all  test  conditions,  but  these 
differences  were  not  statistically  significant  (p  = 
0.09).  None  of  the  differences  in  delivered  Vj. 
between  the  Servo  300  and  the  circle  system 
are  of  clinical  importance.  IMPLICATIONS: 
Our  laboratory  investigation  suggests  that  pres- 
sure-limited ventilation  delivered  by  a  standard 
adult  circle  system  compares  favorably  with  that 
of  freestanding  infant  ventilators  used  in  pres- 
sure-limited mode.  Changing  from  an  adult  cir- 
cle sy.stem  to  a  free-standing  pressure-limited 
ventilator  may  not  sub.stantially  improve  venti- 
lation of  a  low-compliance  infant  lung;  the  ef- 
ficacy of  such  a  practice  should  be  investigated. 

Simulation  Technology  for  Health  Care  Pro- 
fessional Skills  Training  and  Assessment — 

Issenberg  SB.  McGaghie  WC,  Hart  IR,  Mayer 
JW,  Felner  JM,  Petru.sa  ER,  et  al.  JAMA  1999 
Sep  l;282(9):861-866. 

Changes  in  medical  practice  that  limit  instruc- 
tion time  and  patient  availability,  the  expanding 
options  for  diagnosis  and  management,  and  ad- 
vances in  technology  are  contributing  to  greater 


use  of  simulation  technology  in  medical  edu- 
cation. Four  areas  of  high-technology  simula- 
tions currently  being  used  are  laparoscopic  tech- 
niques, which  provide  surgeons  with  an 
opportunity  to  enhance  their  motor  skills  with- 
out risk  to  patients;  a  cardiovascular  disease 
simulator,  which  can  be  used  to  simulate  car- 
diac conditions;  multimedia  computer  systems, 
which  includes  patient-centered,  case-based  pro- 
grams that  constitute  a  generalist  curriculum  in 
cardiology;  and  anesthesia  simulators,  which 
have  controlled  responses  that  vary  according 
to  numerous  possible  scenarios.  Some  benefits 
of  simulation  technology  include  improvements 
in  certain  surgical  technical  skills,  in  cardiovas- 
cular examination  skills,  and  in  acquisition  and 
retention  of  knowledge  compared  with  tradi- 
tional lectures.  These  systems  help  to  address 
the  problem  of  poor  skills  training  and  profi- 
ciency and  may  provide  a  method  for  physi- 
cians to  become  self-directed  lifelong  learners. 

Performance  of  a  Short  Lung-Specific  Health 
Status  Measure  in  Outpatients  with  Chronic 
Obstructive  Pulmonary  Disease — Stavem  K, 
Erikssen  J,  Boe  J.  Respir  Med  1999  Jul;93(7): 
467-475. 

The  objective  of  this  study  was  to  assess  the 
performance  of  a  lung-.specific  health  status 
measure  in  patients  with  chronic  obstructive  pul- 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1433 


Abstracts 


monary  disease  (COPD).  We  used  the  Respira- 
tory Quality  of  Life  Questionnaire  (RQLQ),  a 
modification  of  an  Australian  questionnaire  in- 
tended for  asthma  patients  and  adapted  in  this 
study  to  fit  patients  with  COPD  also.  For  com- 
parison we  chose  the  general  health  profile  mea- 
sure Short  Form  36  (SF-36).  We  assessed  the 
five  RQLQ  scales  and  eight  SF-36  scales  for 
reliability,  validity  and  responsiveness  in  59  out- 
patients attending  a  Norwegian  hospital  for 
COPD.  Statistical  analysis  included  internal 
consistency,  test-retest  reliability  and  conver- 
gent validity  between  the  two  questionnaires. 
Responsiveness  was  assessed  in  patients  report- 
ing global  change  in  health  status  over  1  year. 
All  scales  of  the  RQLQ  showed  good  internal 
consistency  (Cronbach's  a  =  0.85-0.94)  and 
test-retest  reliability  (intraclass  correlation  co- 
efficient =  0.86-0.94),  as  did  the  SF-36  scales 
(a  =  0.66-0.90)  and  intraclass  correlation  co- 
efficient =  0.60-0.86).  Pearson  correlations  be- 
tween scales  with  similar  items  ranged  from 
0.54  to  0.76,  supporting  the  construct  validity 
of  both  questionnaires.  The  RQLQ  had  respon- 
sive scales,  showing  significant  changes  in  the 
expected  direction  over  1  year.  We  conclude 
that  the  RQLQ  showed  an  acceptable  reliabil- 
ity, construct  validity  and  responsiveness  in 
COPD  patients,  encouraging  further  use  of  this 
questionnaire. 

Inhaled  Antibiotic  Therapy  in  Non-Cystic  Fi- 
brosis Patients  with  Bronchiectasis  and 
Chronic  Bronchial  Infection  by  Pseudoino- 
nas  Aeruginosa — Orriols  R,  Roig  J,  Ferrer  J, 
Sampol  G,  Rosell  A,  Ferrer  A,  Vallano  A.  Re- 
spir  Med  1999  Jul;93(7):476-480. 

The  aim  of  this  study  was  to  investigate  the 
long-term  effectiveness  and  safety  of  inhaled 
antibiotic  treatment  in  non-cystic  fibrosis  pa- 
tients with  bronchiectasis  and  chronic  infection 
by  Pseudomonas  aeruginosa,  after  standard  en- 
dovenous  and  oral  therapy  for  long-term  con- 
trol of  the  infection  had  failed.  After  complet- 
ing a  2-week  endovenous  antibiotic  treatment 
to  stabilize  respiratory  status,  17  patients  were 
randomly  allocated  to  a  12-month  treatment  ei- 
ther with  inhaled  ceftazidime  and  tobramycin 
(group  A)  or  a  symptomatic  treatment  (group 
B).  One  patient  from  group  A  abandoned  in- 
haled treatment  because  of  bronchospasm  and 
another  from  group  B  died  before  the  end  of  the 
study.  The  remaining  15  patients,  seven  from 
group  A  and  eight  from  group  B,  completed  the 
study.  Both  groups  had  similar  previous  char- 
acteristics. The  number  of  admissions  and  days 
of  admission  (mean  ±  SEM)  of  group  A  [0.6 
(L5)  and  13.1  (34.8)]  were  lower  than  those  of 
group  B  [2.5  (2.1)  and  57.9  (41.8)]  (p  <  0.05). 
Forced  vital  capacity  (FVC),  forced  expiratory 
volume  in  1  sec  (FEV,),  P„q,  and  Paco,  w^r^ 
similar  in  the  two  groups  at  the  end  of  follow- 
up,  showing  a  comparable  decline  in  these  pa- 
rameters. There  were  no  significant  differences 


either  in  the  use  of  oral  antibiotics  or  in  the 
frequency  of  emergence  of  antibiotic-resistant 
bacteria  between  groups.  Microbiological  stud- 
ies suggested  that  several  patients  had  different 
Pseudomonas  aeruginosa  strains.  None  of  the 
patients  presented  impaired  renal  or  auditory 
function  at  the  end  of  the  study.  This  study 
suggests  that  long-term  inhaled  antibiotic  ther- 
apy may  be  safe  and  lessen  disease  severity  in 
non-cystic  fibrosis  patients  with  bronchiectasis 
and  chronic  bronchial  infection  by  Pseudomo- 
nas aeruginosa  which  do  not  respond  satisfac- 
torily to  antibiotics  administered  via  other 
routes. 

Associations  Between  an  Asthma  Morbidity 
Index  and  Ideas  of  Fright  and  Bother  in  a 
Community  Population — Jones  K,  Cleary  R, 
Hyland  M.  Respir  Med  1 999  Jul;93(7):5 1 5-5 1 9. 

There  is  a  need  for  simple  asthma  outcome  mea- 
sures for  primary  care  which  are  not  only  valid 
in  terms  of  their  relationship  with  lung  function 
but  also  in  terms  of  pragmatic  psychological 
constructs.  This  study  assesses  the  usefulness 
of  adding  items  on  the  degree  of  'bother'  and 
■fright'  caused  by  the  condition  to  a  previously 
validated  simple  asthma  morbidity  index.  A 
postal  questionnaire  survey  comprising  a  sim- 
ple asthma  morbidity  index  and  questions  on 
'fright'  and  'bother'  was  conducted  in  one  gen- 
eral practice  in  the  north-east  of  England.  Re- 
sponses were  obtained  from  570  individuals. 
Of  these,  184  (32%)  reported  low,  133  (23%) 
medium  and  253  (44%)  high  morbidity.  Twen- 
ty-nine per  cent  of  respondents  had  felt  fright- 
ened by  their  asthma  in  the  previous  4  weeks. 
Both  the  'fright'  and  'bother'  items  were  sig- 
nificantly associated  with  the  morbidity  index. 
The  addition  of  'bother'  and/or  'fright'  ques- 
tions may  improve  both  the  content,  construct 
and  predictive  validity  of  the  morbidity  index, 
but  this  needs  to  be  established  prospectively. 

Patient- Ventilator  Asynchrony  During  Non- 
invasive Ventilation:  The  Role  of  Expiratory 
Trigger — Calderini  E,  Confalonieri  M,  Puccio 
PG,  Francavilla  N,  Stella  L,  Gregoretti  C.  In- 
tensive Care  Med  1999  Jul;25(7):662-667. 

OBJECTIVE:  Air  leaks  around  the  mask  are 
very  likely  to  occur  during  noninvasive  venti- 
lation, in  particular  when  prolonged  ventilatory 
treatment  is  required.  It  has  been  suggested  that 
leaks  from  the  mask  may  impair  the  expiratory 
trigger  cycling  mechanism  when  inspiratory 
pressure  support  ventilation  (PSV)  is  used.  The 
aim  of  this  study  was  to  compare  the  short-term 
effect  of  two  different  expiratory  cycling  mech- 
anisms (time-cycled  vs  flow-cycled)  during 
noninvasive  inspiratory  pressure  support  venti- 
lation (NIPSV)  on  patient-ventilator  synchroni- 
sation in  severe  hypoxemic  respiratory  failure. 
STUDY  POPULATION:  Six  patients  with  acute 
lung  injury  (ALI)  due  to  acquired  immunode- 


ficiency syndrome  (AIDS)-related  opportunis- 
tic pneumonia  were  enrolled  in  the  protocol. 
INTERVENTION:  Each  subject  was  first  stud- 
ied during  spontaneous  breathing  with  a  Ven- 
turi  oxygen  mask  (SB)  and  successively  sub- 
mitted to  a  randomly  assigned  20'  conventional 
flow-cycling  (NIPSVfc)  or  time-cycling  inspira- 
tory pressure  support  ventilation  (NIPSVtc).  The 
pre-set  parameters  were:  inspiratory  pressure  of 
10  cm  HjO,  PEEP  of  5  cm  HjO  for  the  same 
inspired  oxygen  fraction  as  during  SB.  A  tight 
fit  of  the  mask  was  avoided  in  order  to  facilitate 
air  leaks  around  the  mask.  The  esophageal  pres- 
sure time  product  (PTPes)  and  tidal  swings  (A 
Pes)  were  measured  to  evaluate  the  patient's 
respiratory  effort.  A  subjective  "comfort  score" 
and  the  difference  between  patient  and  machine 
respiratory  rate  [A  RR(p-v)],  calculated  on 
esophageal  and  airway  pressure  curves,  were 
used  as  indices  of  patient-machine  interaction. 
RESULTS:  Air  leaks  through  the  mask  occurred 
in  five  out  of  six  patients.  The  values  of  PEEPi 
(<  1.9  cm  HjO)  excluded  significant  expira- 
tory muscle  activity.  NIPSVtc  significantly  re- 
duced PTPes,  A  Pes,  and  A  RR(p-v)  when  com- 
pared to  NIPS-Vfc  [230  ±  41  (SE)  vs  376  ±  72 
cm  HjO-s-min-  ';8±2vsl3±2cm  HjO;  I  ± 
1  vs  9  ±  2  br-min"';  respectively]  with  a  con- 
comitant significant  improvement  of  the  "com- 
fort score".  CONCLUSIONS:  In  the  presence 
of  air  leaks  a  time-cycled  expiratory  trigger  pro- 
vides a  better  patient-machine  interaction  than 
a  flow-cycled  expiratory  trigger  during  NIPSV. 

Aspiration  of  Dead  Space  Allows  Normocap- 
nic  Ventilation  at  Low  Tidal  Volumes  in 

Man — De  Robertis  E,  Servillo  G,  Jonson  B, 
Tufano  R.  Intensive  Care  Med  1999  Jul;25(7): 
674-679. 

OBJECTIVE:  Aspiration  of  dead  space  (AS- 
PIDS)  improves  carbon  dioxide  (COj)  elimina- 
tion by  replacing  dead  space  air  rich  in  COj 
with  fresh  gas  during  expiration.  The  hypothe- 
sis was  that  ASPIDS  allows  normocapnia  to  be 
maintained  at  low  tidal  volumes  (Vt).  DESIGN: 
Prospective  study.  SETTING:  Adult  intensive 
care  unit  in  a  university  hospital.  PATIENTS: 
Seven  patients  ventilated  for  neurological  rea- 
sons were  studied.  All  patients  were  clinically 
and  haemodynamically  stable  and  monitored  ac- 
cording to  clinical  needs.  INTERVENTIONS: 
ASPIDS  implies  that,  during  expiration,  gas  is 
aspirated  through  a  catheter  inserted  in  the  tra- 
cheal tube.  Simultaneously,  a  compensatory 
flow  of  fresh  gas  is  injected  into  the  inspiratory 
line.  ASPIDS  was  achieved  with  a  computer/ 
ventilator  system  controlling  two  solenoid 
valves  for  aspiration  and  injection.  RESULTS: 
At  the  basal  respiratory  rate  of  12.6  breaths 
min',  with  ASPIDS  V^  decreased  from  602  to 
456  mL,  as  did  the  airway  pressures  to  a  cor- 
responding degree.  P„co2  ^^^  Pao,  remained  sta- 
ble. At  a  frequency  of  20  breaths  min',  with 
ASPIDS  Vt-  was  further  reduced  to  305  mL 


1434 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Portex®  Arterial  Blood  Sampling  Devices 


When  the  chemistry  is  right, 
the  possibilities  are  endless. 


The  right  chemistry  can  spark 
great  relationships,  inspire 
genius,  and  produce  medical 
breakthroughs.  Case  in  point: 
Portex*  advanced  formula 
heparin  makes  arterial  blood 
sampling  easier,  more  accurate, 
and  more  efficient,  permitting 
1 1  tests  from  a  single  sample. 
With  such  inspired 
innovations,  the  relationship 
between  our  ABS  products  and 
discriminating  clinicians  will 
go  on  forever. 

Our  chemistry  is  so 
right  that  one  sample  is 
all  you  need  for  11  tests. 

Our  advanced  formula  heparin 
combines  the  necessary 
anticoagulant  effect  with 
calcium-neutral  heparin  for 
more  accurate,  more  extensive 
testing  from  a  single  sample. 
Ours  is  the  first  and  only 
heparin  formula  that  can 
measure  1 1  indications  from 
one  arterial  blood  sample. 


Endless  possibilities, 
more  products,  lots  of 
safety  features. 

SIMS  Portex  Inc.  offers  more 
product  choices  than  any  other 
manufacturer — liquid  and  dry 
heparin,  with  syringe  sizes 
ranging  from  1  cc  to  3  cc. 


DopulalKin  HM  conpoMd  of  KXI  wd  Ell  pM«W 


For  fuithet  information,  contact: 


We  also  help  to  eliminate  the 
frightening  possibility  of 
needlesticks  with  our  patented 
Needle-Pro®  needle  protection 
device;  the  Filter-Pro*  air 
bubble  removal  device  is 
standard  on  all  our  syringes. 

That  special  spark? 

There  is  a  special  chemistry 
between  SIMS  Portex  Inc.  and 
the  clinicians  who  use  our 
products,  a  relationship  built 
on  trust,  support,  and 
reliability.  Clinicians  prefer 
our  blood  sampling  devices  for 
obvious  reasons:  they  are  safer, 
easier  to  use,  and  less 
traumatic  for  patients. 

Newly  released  on 
videotape. 

Call  us,  toll-free,  to  get  your 
tape  of  our  newest  video 
release  on  arterial  blood 
sampling  devices  and 
techniques.  Ask  for  Nicole 
Hall,  1-800-258-5361, 
prompt  4,  ext  226. 


i 


SIMS  Portex  Inc. 

800-258-5361  or  Fax  603-352-3703 
www.portexusa.com 


Sims 


^  SMfTHB  INOUSTniEa 

I"  Medical  Systems 


SIMS,  Ponex,  Pro-Vent,  Needle-Pro,  and  Filter-Pro  are  SIMS  trademarks.  Point-Lok  is  a  trademark  of  Noved  Medical. 

Circle  130  on  product  Info  card 
Visit  Booth  431  in  Las  Vegas 


Needle-Pro* 
Needle  Protection 

Devices  for 

Maximum  Needle 

Protection  for 

Clinicians 


Filter-Pro" 

Devices  for  Easy 

Removal  of  Air 

Bubbles 


High  Level  of 

Performance  for 

11  Indications 


Complete  Family 
of  Line  Draw 
Syringes  for 
Direct  Blood 

Sampling  from  an 
Arterial  Line 


ei999  SIMS  Portex  Inc. 


Abstracts 


with  preserved  normocapnia.  ASPIDS  did  not 
interfere  with  the  positive  end-expiratory  pres- 
sure (PEEP)  level.  No  intrinsic  PEEP  devel- 
oped. All  patients  remained  stable.  No  haemo- 
dynamic  or  other  side  effects  of  ASPIDS  were 
noticed.  CONCLUSION:  The  results  of  this 
study  suggest  that  ASPIDS  may  be  a  useful  and 
safe  modality  of  mechanical  ventilation  that  lim- 
its alveolar  pressure  and  minute  ventilation  re- 
quirements while  keeping  P,,c(),  constant. 

Sensitivity  and  Specificity  of  a  Screening  Test 
to  Document  Traumatic  Experiences  and  to 
Diagnose  Post-Traumatic  Stress  Disorder  in 
ARDS  Patients  after  Intensive  Care  Treat- 
ment— Stoll  C,  Kapfhammer  HP.  Rothen- 
hausler  HB,  Haller  M,  Briegel  J,  Schmidt  M.  et 
al.  Intensive  Care  Med  1999  Jul;25(7):697-704. 

OBJECTIVE:  Many  survivors  of  critical  illness 
and  intensive  care  unit  (ICU)  treatment  have 
traumatic  memories  such  as  nightmares,  panic 
or  pain  which  can  be  associated  with  the  de- 
velopment of  posttraumatic  stress  disorder 
(PTSD).  In  order  to  simplify  the  rapid  and  early 
detection  of  PTSD  in  such  patients,  we  modi- 
fied an  existing  questionnaire  for  diagnosis  of 
PTSD  and  validated  the  instrument  in  a  cohort 
of  ARDS  patients  after  long-term  ICU  therapy. 
DESIGN:  Follow-up  cohort  study.  SETTING: 
The  20-bed  ICU  of  a  university  teaching  hos- 
pital. PATIENTS:  A  cohort  of  52  long-term 
survivors  of  the  acute  respiratory  distress  syn- 
drome (ARDS).  INTERVENTIONS  AND 
MEASUREMENTS:  The  questionnaire  was  ad- 
ministered to  the  study  cohort  at  two  time  points 
2  years  apart.  At  the  second  evaluation,  the  pa- 
tients underwent  a  structured  interview  with  two 
trained  psychiatrists  to  diagnose  PTSD  accord- 
ing to  Diagnostic  and  Statistical  Manual  of  Men- 
tal Disorders,  4th  edition  (DSM-IV)  criteria.  The 
reliability  and  validity  of  the  questionnaire  was 
then  estimated  and  its  specificity,  sensitivity  and 
optimal  decision  threshold  determined  using  re- 
ceiver operating  characteristic  (ROC)  curve 
analyses.  RESULTS:  The  questionnaire  showed 
a  high  internal  consistency  (Crohnbach's  al- 
pha =  0.93)  and  a  high  test-retest  reliability 
(intraclass  correlation  coefficient  alpha  =  0.89). 
There  was  evidence  of  construct  validity  by  a 
linear  relationship  between  scores  and  the  num- 
ber of  traumatic  memories  from  the  ICU  the 
patients  described  (Spearman's  rho  =  0.48,  p  < 
0.01).  Criterion  validity  was  demon.strated  by 
ROC  curve  analyses  resulting  in  a  sensitivity  of 
77.0%  and  a  specificity  of  97.5%  for  the  diag- 
nosis of  PTSD.  CONCLUSIONS:  The  ques- 
tionnaire was  found  to  be  a  responsive,  valid 
and  reliable  instrument  to  screen  survivors  of 
intensive  care  for  PTSD. 

Comparison  of  Different  Methods  for  Dead 
Space  Measurements  in  Ventilated  Newborns 
Using  COj- Volume  Plot— Wenzel  U.  Wauer 


RR.  Schmalisch  G.  Intensive  Care  Med  1999 
Jul;25(7):705-713. 

OBJECTIVE:  The  aim  of  the  study  was  to  test 
the  applicability  of  Ventrak  1550/Capnogard 
1 265  ( V-C)  for  respiratory  dead  space  ( V^)  mea- 
surement and  to  determine  anatomic  (V[,,,„.,). 
physiologic  (V^phy,),  and  alveolar  dead  spaces 
(^Daiv)  i"  ventilated  neonates.  DESIGN:  Pro- 
spective study.  SETTING:  Neonatal  intensive 
care  unit.  PATIENTS:  33  investigations  in  22 
ventilated  neonates;  median  gestational  age  34.5 
weeks  (range  27-41).  median  birthweight 
2658  g  (range  790-3940).  METHOD:  The  sin- 
gle-breath CO,  test  (SBT-COj)  and  tran,scuta- 
neous  partial  pressure  of  carbon  dioxide  (Pco,) 
were  recorded  simultaneously  and  Vp,  was  de- 
termined (1)  automatically  (V-C  software).  (2) 
by  interactive  analysis  of  the  P^-q,  volume  plot, 
and  (3)  manually  by  Bohr/Enghoff  equations 
using  data  obtained  by  V-C.  RESULTS:  V„ 
measurements  were  possible  in  all  cases  by 
method  3  but  not  possible  by  methods  I  and  2 
in  22  of  33  investigations  (67%),  especially  in 
preterm  neonates,  because  of  disturbed  signals. 
VixMvAg  ( 1  f"  ±  O-ft  mL/kg,  mean  ±  SD),  V„.,J 
tidal  volume  (V-,)  (0.36  ±  0.09)  were  lower 
compared  to  published  data  in  spontaneously 
breathing  infants,  whereas  V|-,p|,y„/kg  (2.3  ±  0.9 
mL/kg)  and  V,,^„^J\/y  (0.50  ±0.12)  are  com- 
parable to  data  obtained  from  the  literature.  Five 
minutes  after  insertion  of  the  sensor  (dead  space 
2.6  mL)  into  the  ventilatory  circuit,  the  trans- 
cutaneous P((,,  rose  above  baseline  for  3.2% 
(patients  >  2500  g)  and  5.7%  (patients  < 
2500  g).  The  time  necessary  for  one  analysis 
was  50-60  min.  CONCLUSION:  In  ventilated 
newborns,  dead  space  measurements  were  pos- 
sible only  in  one-third  by  SBT-CO,.  but  in  all 
cases  by  Bohr/Enghoff  equations.  Improved 
software  could  further  reduce  the  time  needed 
for  one  analysis. 

Combination  of  Inhaled  Nitric  Oxide  and  In- 
travenous Prostacyclin  for  Successful  Treat- 
ment of  Severe  Pulmonary  Hypertension  in 
a  Patient  with  Acute  Respiratory  Distress 
Syndrome— Kuhlen  R.  Walbert  E,  Frankel  P, 
Thaden  S,  Behrendt  W,  Rossaint  R.  Intensive 
Care  Med  1999  Jul:25(7):752-754. 

OBJECTIVE:  To  investigate  the  combination 
of  inhaled  nitric  oxide  (iNO)  and  intravenously 
administered  prostacyclin  (i.v.  PGI2)  in  a  pa- 
tient with  severe  pulmonary  hypertension  and 
acute  respiratory  distress  syndrome  (ARDS). 
DESIGN:  Single  case  study.  SETTING:  Inten- 
sive care  unit  of  a  university  hospital.  METH- 
ODS: In  an  ARDS  patient  with  severe  pulmo- 
nary hypertension,  gas  exchange  and 
hemodynamics  were  measured  during  combined 
treatment  with  iNO  and  i.v.  PGI2.  On  two  sub- 
sequent days,  a  protocol  consisting  of  four  20- 
min  periods  was  performed:  baseline.  10  ppm 
iNO,  10  ppm  iNO  plus  4  ng  kg  '  min"',  and  4 


ng  kg*'  min"'  PGI2  alone.  At  the  end  of  each 
period  hemodynamic  and  gas  exchange  data 
were  obtained.  RESULTS:  The  combination  of 
iNO  and  i.v.  PGI2  resulted  in  a  marked  de- 
crease in  pulmonary  artery  pressure  and  a  con- 
comitant increase  in  cardiac  output  which  was 
more  pronounced  than  the  effect  of  either  drug 
alone.  During  iNO.  as  well  as  during  the  com- 
bination of  iNO  and  i.v.  PGI2.  oxygenation  was 
improved,  whereas  during  i.v.  PGI2  alone  ox- 
ygenation was  worse  than  baseline.  CONCLU- 
SION: We  conclude  that  the  combination  of 
iNO  and  i.v.  PGI2  might  be  more  u.seful  than 
either  drug  alone  when  severe  pulmonary  hy- 
pertension leading  to  impaired  right  ventricular 
function  is  present  in  ARDS.  A  systematic  study 
of  this  observation  is  warranted. 

Sublingual  Capnometry:  A  New  Noninvasive 
Measurement  for  Diagnosis  and  Quantita- 
tion of  Severity  of  Circulatory  Shock — Weil 
MH.  Nakagawa  Y.  Tang  W.  Sato  Y.  Ercoli  F, 
Finegan  R,  et  al.  Crit  Care  Med  1999  Jul;27(7): 
1225-1229. 

OBJECTIVE:  To  investigate  the  feasibility  and 
predictive  value  of  sublingual  P^,„  (P(SL)CO,) 
measurements  as  a  noninvasive  and  early  indi- 
cator of  systemic  perfusion  failure.  DESIGN:  A 
prospective,  criterion  study.  SETTING:  Emer- 
gency department  and  medical  and  surgical  in- 
tensive care  units  of  an  urban  community  med- 
ical center.  PARTICIPANTS  AND  PATIENTS: 
Five  normal  human  volunteers  and  46  patients 
with  acutely  life-threatening  illness  or  injuries. 
INTERVENTIONS:  Intra-arterial  or  automated 
cuff  blood  pressure  and  arterial  blood  lactate 
(LAC)  were  measured  concurrently  with 
P(SL)CO,.  RESULTS:  P(SL)C02  in  five 
healthy  volunteers  was  45.2  ±  0.7  mm  Hg 
(mean  ±  sD).  Twenty-.six  patients  with  physi- 
cal signs  of  circulatory  shock  and  LAC  >2.5 
mmol/L  had  a  P(SL)CO,  of  81  ±  24  mm  Hg. 
This  contrasted  with  patients  admitted  without 
clinical  signs  of  shock  and  LAC  of  <2.5  mmol/L 
who  had  a  P(SL)CO,  of  53  ±  8  mm  Hg  (p  < 
0.(X)1 ).  The  initial  P(SL)CO,  of  12  patients  who 
died  before  recovery  from  shock  was  93  ±  27 
mm  Hg,  and  this  contrasted  with  58  ±  11  mm 
Hg  (p  <  0.001 )  in  hospital  survivors.  Increases 
in  P(SL)C02  were  correlated  with  increases  in 
LAC  (r-  =  0.84;  p  <  0.001).  When  P(SL)CO, 
exceeded  a  threshold  of  70  mm  Hg.  its  positive 
predictive  value  for  the  presence  of  physical 
signs  of  circulatory  shock  was  1 .00.  When  it 
was  <70  mm  Hg,  it  predicted  survival  with  a 
predictive  value  of  0.93.  CONCLUSION: 
P(SL)C02  may  serve  as  a  technically  simple 
and  noninvasive  clinical  measurement  for  the 
diagnosis  and  estimation  of  the  severity  of  cir- 
culatory shock  states. 

Enteral  Tube  Feeding  in  the  Intensive  Care 
Unit:  Factors  Impeding  Adequate  Delivery — 

McClave  SA.  Sexton  LK,  Spain  DA,  Adams 


143fc 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Draser 


"Resistance  is  futile!" 

During  ventilation  the  artificial  airway  resistance  makes  breathing  more  difficult.  The  use  of  pressure 
support  as  a  simple  means  to  overcome  this  resistance  has  fundamental  disadvantages.  Conventional 
pressure  support  cannot  adapt  to  specific  breath  to  breath  requirements  due  to  patient  demand  and  is 
only  active  during  the  inspiratory  phase. 

Automatic  tube  compensation  (ATC™)  now  offers  continuous  adaptation  to  the  current  gas  flow  through- 
out the  entire  respiratory  cycle  virtually  eliminating  the  additional  work  of  breathing  generated  by  the  tube 

(WOBtube). 

Today  and  tomorrow.. .Drager  the  leader  in  innovative  development  for  ventilation. 


without  ATC 


WOB  I 


with  ATC 


Drager.Technology  for  Life. 


Circle  123  on  product  info  card 
Visit  Booth  725  in  Las  Vegas 


Drager  Medical,  Inc. 
800-437-2437  (800-4DRAGER) 
vvww.draegermedical.com 


Abstracts 


JL,  Owens  NA,  Sullins  MB,  et  al.  Crit  Care 
Med  1999  Jul;27(7);  1252-1 256. 

OBJECTIVE:  To  evaluate  those  factors  that  im- 
pact on  the  delivery  of  enteral  lube  feeding. 
DESIGN:  Prospective  study.  SETTING:  Med- 
ical intensive  care  units  (ICU)  and  coronary 
care  units  at  two  university-based  hospitals.  PA- 
TIENTS: Forty-four  medical  ICU/coronary  care 
unit  patients  (mean  age,  57.8  yrs;  70%  male) 
who  were  to  receive  nothing  by  mouth  and  were 
placed  on  enteral  tube  feeding.  INTERVEN- 
TIONS: Rate  of  enteral  tube  feeding  ordered, 
actual  volume  delivered,  patient  position,  resid- 
ual volume,  flush  volume,  presence  of  blue  food 
coloring  in  oropharynx,  and  stool  frequency 
were  recorded  every  4  hrs.  Duration  and  reason 
for  cessation  of  enteral  tube  feeding  were  doc- 
umented. MEASUREMENTS  AND  MAIN  RE- 
SULTS: Physicians  ordered  a  daily  mean  vol- 
ume of  enteral  tube  feeding  that  was  65.6%  of 
goal  requirements,  but  an  average  of  only  78. 1  % 
of  the  volume  ordered  was  actually  infused. 
Thus,  patients  received  a  mean  volume  of  en- 
teral tube  feeding  for  all  339  days  of  infusion 
that  was  5 1 .6%  of  goal  (range,  15. 1  %  to  87. 1  %). 
Only  14%  of  patients  reached  >  90%  of  goal 
feeding  (for  a  single  day)  within  72  hrs  of  the 
start  of  enteral  tube  feeding  infusion.  Of  24 
patients  weighed  before  and  after,  54%  were 
noted  to  lose  weight  on  enteral  tube  feeding. 
Declining  albumin  levels  through  the  enteral 
tube  feeding  period  correlated  significantly  with 
decreasing  percent  of  goal  calories  infused  (p  = 
0.042;  r^  =  0.13).  Diarrhea  occurred  in  23  pa- 
tients (52.3%)  for  a  mean  38.2%  of  enteral  tube 
feeding  days.  In  >1490  bedside  evaluations, 
patients  were  observed  to  be  in  the  supine  po- 
sition only  0.45%,  residual  volume  of  >200 
mL  was  found  2.8%,  and  blue  food  coloring 
was  found  in  the  oropharynx  5.1%  of  the  time. 
Despite  this,  cessation  of  enteral  tube  feeding 
occurred  in  83.7%  of  patients  for  a  mean  19.6% 
of  the  potential  infusion  lime.  Sixty-six  percent 
of  the  enteral  tube  feeding  cessations  was  judged 
to  be  attributable  to  avoidable  causes.  CON- 
CLUSIONS: The  current  manner  in  which  en- 
teral tube  feeding  is  delivered  in  the  ICU  results 
in  grossly  inadequate  nutritional  support.  Barely 
one  half  of  patient  caloric  requirements  are  met 
because  of  underordering  by  physicians  and  re- 
duced delivery  through  frequent  and  often  in- 
appropriate cessation  of  feedings. 

Single  Versus  Multiple  Doses  of  Acetazol- 
amide  for  Metabolic  Alkalosis  in  Critically 
III  Medical  Patients:  A  Randomized,  Dou- 
ble-Blind Trial— Mazur  JE,  Devlin  JW,  Peters 
MJ,  Jankowski  MA,  lannuzzi  MC,  Zarowitz  BJ. 
Crit  Care  Med  1999  Jul;27(7):  1257-1 261. 

OBJECTIVE:  To  compare  two  dosing  regimens 
of  acetazolamide  for  the  reversal  of  metabolic 
alkalosis  in  mechanically  ventilated  patients 
with  asthma  or  chronic  obstructive  pulmonary 


disease.  DESIGN:  A  randomized,  double-blind, 
placebo-controlled  trial.  SETTING:  A  35-bed 
medical  intensive  care  unit  in  a  tertiary  care 
teaching  hospital.  PATIENTS:  Forty  mechani- 
cally ventilated  patients  with  a  metabolic  alka- 
losis (arterial  pH  a  7.48  and  serum  bicarbonate 
concentration  a  26  mEq/L)  resistant  to  fluid  or 
potassium  therapy  (serum  potassium  concentra- 
tion, a  4  mEq/L)  not  receiving  acetazolamide 
or  sodium  bicarbonate  in  the  previous  72  hrs. 
INTERVENTIONS:  Stratified  by  previous  di- 
uretic use  and  randomized  to  receive  intrave- 
nous administration  of  acetazolamide,  one  dose 
of  500  mg  or  250  mg  every  6  hrs  for  a  total  of 
four  doses.  MEASUREMENTS  AND  MAIN 
RESULTS:  Serum  bicarbonate  and  potassium 
concentrations  were  drawn  every  6  hrs  for  72 
hrs,  arterial  blood  gases  were  drawn  every  12 
hrs  for  72  hrs,  and  both  urine  chloride  and  pH 
were  drawn  at  hours  0,  6,  12,  18,  24, 48,  and  72. 
By  using  generalized  estimating  equation  tech- 
niques, no  difference  was  found  between  the 
two  dosing  regimens  at  any  point  over  the  study 
period  for  serum  bicarbonate,  serum  potassium, 
or  urine  chloride  end  points.  Results  did  not 
differ  between  diuretic-  and  nondiuretic-treated 
patients.  Serum  bicarbonate  concentrations  re- 
mained significantly  decreased  in  both  treat- 
ment groups  72  hrs  after  administration  of  the 
first  acetazolamide  dose  (31.8  ±  4.9-25.3  ± 
3.8  mEq/L,  p  <  0.0001  [250  mg  x  4];  31.9  ± 
25.4-25.4  ±  3.6  mEq/L,  p  <  0.0001  [500  mg 
x  I]).  CONCLUSIONS:  We  conclude  that  a 
single  500-mg  dose  of  acetazolamide  reverses 
nonchloride  responsive  metabolic  alkaloses  in 
medical  intensive  care  unit  patients  as  effec- 
tively as  multiple  doses  of  250  mg.  Studies  to 
examine  the  prolonged  duration  of  action  of 
acetazolamide  observed  in  this  study  as  well  as 
the  effect  of  acetazolamide  on  clinical  end 
points,  such  as  duration  of  mechanical  ventila- 
tion, are  warranted. 

Motor  Activity  Assessment  Scale:  A  Valid 
and  Reliable  Sedation  Scale  for  Use  with  Me- 
chanically Ventilated  Patients  in  an  Adult 
Surgical  Intensive  Care  Unit — Devlin  JW, 
Boleski  G,  Mlynarek  M,  Nerenz  DR,  Peterson 
E,  Jankowski  M,  et  al.  Crit  Care  Med  1999 
Jul;27(7):1271-I275. 

OBJECTIVE:  To  establish  the  validity  and  re- 
liability of  a  new  .sedation  scale,  the  Motor  Ac- 
tivity Assessment  Scale  (MAAS).  DESIGN: 
Prospective,  psychometric  evaluation.  SET- 
TING: Sixteen-bed  surgical  intensive  care  unit 
(SICU)  of  a  937-bed  tertiary  care,  university- 
affiliated  teaching  hospital.  PATIENTS:  Twen- 
ty-five randomly  selected,  adult,  mechanically 
ventilated,  nonneurosurgical  patients  who  were 
admitted  to  the  SICU  a  12  hrs  after  surgery 
and  were  not  receiving  neuromuscular  block- 
ers. INTERVENTION:  Four  hundred  assess- 
ments (eight  per  patient)  were  completed  con- 
secutively but  independently,  in  pairs,  at 


standardized  times  (both  day  and  night)  by  two 
nurses  who  were  preselected  for  each  assess- 
ment from  a  pool  of  32  pretrained  SICU  nurses. 
MEASUREMENTS  AND  MAIN  RESULTS: 
To  estimate  validity,  paired  assessments  (four/ 
patient)  compared  the  MAAS  result  with  the 
subjective  assessment  using  a  lO-cm  visual  an- 
alog sedation  scale,  the  percent  change  in  blood 
pressure  and  heart  rate  from  the  previous  4-hr 
baselines,  and  the  number  of  recent  agitation- 
related  sequelae.  To  estimate  reliability,  paired 
assessments  (four/patient)  measured  correlation 
between  assessments  of  the  same  type  (e.g., 
MAAS-MAAS).  Generalized  estimating  equa- 
tions, which  accounted  for  the  four  repeated 
measures  in  each  patient,  supported  MAAS  va- 
lidity by  finding  a  linear  trend  between  MAAS 
and  the  visual  analog  scale  (p  <  0.001),  blood 
pressure  (p  <  0.001),  heart  rate  (p  <  0.001), 
and  agitation-related  sequelae  (p  <  0.001)  end 
points.  The  MAAS  (kappa  =  0.83  [95%  con- 
fidence interval,  0.72  to  0.94])  was  found  to  be 
more  reliable  than  subjective  assessment  using 
the  visual  analog  scale  (intraclass  correlation 
coefficient  =  0.32  [95%  confidence  interval, 
0.05  to  0.55]).  CONCLUSIONS:  The  MAAS  is 
a  valid  and  reliable  sedation  scale  for  use  with 
mechanically  ventilated  patients  in  the  SICU. 
Further  studies  are  warranted  regarding  the  ef- 
fect of  MAAS  implementation  in  our  SICU  on 
patient  outcomes,  such  as  quality  of  sedation 
and  length  of  mechanical  ventilation,  as  well  as 
the  use  of  the  MAAS  in  other  patient  popula- 
tions (e.g.,  medical). 

Prospective  Evaluation  of  the  Sedation-Agi- 
tation Scale  for  Adult  Critically  III  Patients — 

Riker  RR,  Picard  JT,  Eraser  GL.  Crit  Care  Med 
1999  Jul;27(7):1325-1329. 

OBJECTIVE:  Subjective  scales  to  assess  agi- 
tation and  sedation  in  adult  intensive  care  unit 
(ICU)  patients  have  rarely  been  tested  for  va- 
lidity or  reliability.  We  revised  and  prospec- 
tively tested  the  Sedation-Agitation  Scale  (SAS) 
for  interrater  reliability  and  compared  it  with 
the  Ramsay  scale  and  the  Harris  scale  to  test 
construct  validity.  DESIGN:  A  convenience 
sample  of  ICU  patients  was  simultaneously  and 
independently  examined  by  pairs  of  trained  eval- 
uators  by  using  the  revised  SAS,  Ramsay,  and 
Harris  Scales.  SETTING:  Multidisciplinary  34- 
bed  ICU  in  a  nonuniversity,  academic  medical 
center.  PATIENTS:  Forty-five  ICU  patients 
(surgical  and  medical)  were  examined  a  total  of 
69  times  by  evaluator  pairs.  MEASUREMENTS 
AND  MAIN  RESULTS:  The  mean  patient  age 
was  63.2  yrs,  36%  were  female,  and  71%  were 
intubated.  When  classified  by  using  SAS,  45% 
were  anxious  or  agitated  (SAS  5  to  7),  26% 
were  calm  (SAS  4),  and  29%  were  sedated  (SAS 
1  to  3).  Interrater  correlation  was  high  for  SAS 
(r^  =  .83;  p  <  0.001)  and  the  weighted  kappa 
score  for  interrater  agreement  was  0.92  (p  < 
0.001).  Of  41  assessments  scored  as  Ramsay  I, 


1438 


Respiratory  Care  •  December  1999  Vol  44  No  12 


The    «  f  « 


of  an  MIDI 
a  small  volume  #^^ 


ulizer. 

LC/lv.^^Vli|^ 


Breath-Actuated 
Nebulizer  ("BAN") 

I 

A  new  technology. 

Breath  actuation  is  the  most  significant  advancement  in  the  history  ot  small 
volume  nebulizers  (SVN).  Only  the  AeroEclipse™  BAN  can  deliver  the 
precision  of  an  MDI  in  an  SVN. 

Match  delivery  to  demand. 

The  AeroEclipse™  BAN  creates  aerosol  only  in  precise  response  to  the 
patient's  inspiratory  maneuver.  This  is  patient  on-demand  tiierapy  and 
means  less  medication  waste,  safer  environments  and  clinical  dose 
assurance.  Truly  exceptional  aerosol  performance  delivers  more  drug  - 
faster  and  to  the  right  place  -  creating  a  treatment  modality  without  equal. 

First  time  precision. 

So  why  not  do  it  right  the  first  time  with  the  AeroEclipse™  BAN. ...  After 
all,  when  will  you  have  the  time  to  do  it  again? 

Circle  127  on  product  info  card 

Visit  Booth  1031  in  Las  Vegas 


Now  available  from: 


iBWrS^TTCTtfl 


Monaghan  Medical  Corporation 

PO  Box  2805  •  Plattsburgfi,  NY  12901-0299 
Customer  Service  800-833-9653 
'^AeroEclipse  is  a  trademark  o{  Monaghan  Medical  Corg.pr^licg],,^.,,^.^ 
©1999  Monaghan  Medical  Cqra|^^lte^'^^ 


Abstracts 


49%  scored  SAS  6.  41  %  were  SAS  5,  5%  were 
SAS  4.  and  2%  each  were  SAS  3  or  7.  SAS  was 
highly  correlated  with  the  Ramsay  (r"  =  0.83; 
p  <  0.001)  and  Harris  (r"  =  0.86;  p  <  0.001) 
scales.  CONCLUSIONS:  SAS  is  both  reliable 
(high  interrater  agreement)  and  valid  (high  cor- 
relation with  the  Harris  and  Ramsay  scales)  in 
assessing  agitation  and  sedation  in  adult  ICU 
patients.  SAS  provides  additional  information 
by  stratifying  agitation  into  three  categories 
(compared  with  one  for  the  Ramsay  scale)  with- 
out sacrificing  validity  or  reliability. 

Clinical  Uses  and  Controversies  of  Neuro- 
muscular Blocking  Agents  in  Infants  and 
Children  (review) — Martin  LD,  Bratton  SL. 
O'Rourke  PP.  Crit  Care  Med  1999  Jul;27(7): 
1358-1368. 

OBJECTIVE:  To  review  the  pharmacology  of 
neuromuscular  blocking  drugs  (NMBDs).  their 
use  in  critically  ill  or  injured  infants  and  chil- 
dren, and  the  relevance  of  developmental 
changes  in  neuromuscular  tran.smission.  DATA 
SOURCES:  Computerized  search  of  the  medi- 
cal literature,  STUDY  SELECTION:  Studies 
specifically  examining  the  following  were  re- 
viewed: a)  the  developmental  changes  in  neu- 
romuscular transmission;  b)  the  pharmacokinet- 
ics and  pharmacodynamics  of  all  clinically 
available  NMBDs  in  neonates,  infants,  children, 
and  adults;  and  c)  clinical  experience  with 
NMBDs  in  the  critical  care  setting.  Particular 
attention  was  directed  toward  studies  in  the  pe- 
diatric population.  DATA  SYNTHESIS:  Neu- 
romuscular transmission  undergoes  matura- 
tional  changes  during  the  first  2  months  of  life. 
Alterations  in  body  composition  and  organ  func- 
tion affect  the  pharmacokinetics  and  pharma- 
codynamics of  the  NMBDs  throughout  active 
growth  and  development.  Numerous  NMBDs 
have  been  developed  during  the  last  two  de- 
cades with  unique  pharmacologic  profiles  and 
potential  clinical  advantages.  The  NMBDs  are 
routinely  used  in  critically  ill  or  injured  patients 
of  all  ages.  This  widespread  use  is  as.sociated 
with  rare  but  significant  clinical  complications, 
.such  as  prolonged  weakness.  CONCLUSIONS: 
Significant  gaps  in  our  knowledge  of  the  phar- 
macokinetics and  pharmacodynamics  of 
NMBDs  in  infants  and  children  continue  to  ex- 
ist. Alterations  in  electrolyte  balance  and  or- 
gan-specific drug  metabolism  may  contribute 
to  complications  with  the  use  of  NMBDs  in  the 
critical  care  arena. 

Vaporized  Perfluorocarbon  Improves  Oxy- 
genation and  Pulmonary  Function  in  an 
Ovine  Model  of  Acute  Respiratory  Distress 
Syndrome — Bleyl  JU.  Ragaller  M.  Tscho  U, 
Regner  M.  Kanzow  M.  Hubler  M,  et  al.  Anes- 
thesiology 1999  Aug;91(2):461-469. 

BACKGROUND:  Perfluorocarbon  liquids  are 
lieing  used  experimentally  and  in  clinical  trials 


for  the  treatment  of  acute  lung  injury.  Their 
resemblance  to  inhaled  anesthetic  agents  sug- 
gests the  possibility  of  application  by  vaporiza- 
tion. The  authors'  aim  was  to  develop  the  tech- 
nical means  for  perfluorocarbon  vaporization 
and  to  investigate  its  effects  on  gas  exchange 
and  lung  function  in  an  ovine  model  of  oleic 
acid-induced  lung  injury.  METHODS:  Two  va- 
porizers were  calibrated  for  perfluorohexane  and 
connected  sequentially  in  the  inspiratory  limb 
of  a  conventional  anesthetic  machine.  Twenty 
sheep  were  ventilated  in  a  volume  controlled 
mode  at  an  inspired  oxygen  fraction  of  1 .0.  Lung 
injury  was  induced  by  intravenous  injection  of 
0.1  mL  oleic  acid  per  kilogram  body  weight. 
Ten  sheep  were  treated  with  vaporized  perflu- 
orohexane for  30  min  and  followed  for  2  h;  10 
sheep  served  as  controls.  Measurements  of  blood 
gases  and  respiratory  and  hemodynamic  param- 
eters were  obtained  at  regular  intervals.  RE- 
SULTS: Vaporization  of  perfluorohexane  sig- 
nificantly increased  arterial  oxygen  tension  30 
min  after  the  end  of  treatment  (p  <  0.01).  At 
2  h  after  treatment  the  oxygen  tension  was 
376±182  mm  Hg  (mean  ±  SD).  Peak  inspira- 
tory pressures  (p  <  0.01 )  and  compliance  (p  < 
0.01)  were  significantly  reduced  from  the  end 
of  the  treatment  interval  onward.  CONCLU- 
SION: Vaporization  is  a  new  application  tech- 
nique for  perfluorocarbon  that  significantly  im- 
proved oxygenation  and  pulmonary  function  in 
oleic  acid-induced  lung  injury. 

Assessing  the  Relative  Quality  of  Anesthe.si- 
ology  and  Critical  Care  Medicine  Internet 
Mailing  Lists — Hernandez-Borges  AA,  Ma- 
cias-Cervi  P,  Gaspar-Guardado  MA,  Torres- 
Alvadez  de  Arcaya  ML,  Ruiz-Rabaza  A, 
Ormazabal-Ramos  C.  Anesth  Analg  1999  Aug; 
89(2):520-525. 

We  studied  the  relative  quality  of  a  subset  of 
anesthesiology  and  critical  care  medicine  Inter- 
net mailing  lists  regarding  the  publishing  ca- 
pacity of  their  inembers  to  compare  them  with 
the  major  journals  and  conferences  regarding 
these  specialties.  Using  systematic  searches  on 
MEDLINE  and  according  to  the  Science  Cita- 
tion Index  1995,  we  investigated  the  impact 
factor  of  mailing  list  subscribers,  of  the  first 
authors  of  the  selected  articles,  and  of  the  first 
authors  of  published  abstracts  froin  conferences. 
We  studied  six  mailing  lists,  seven  journals, 
and  four  conferences.  Journals  and  conferences 
showed  a  higher  percentage  of  published  au- 
thors and  higher  average  impact  factor  among 
their  first  authors  than  the  mailing  lists  did  per 
subscriber.  However,  when  only  the  subset  of 
publishing  authors  from  the  three  media  was 
considered,  no  significant  differences  were 
found.  We  conclude  that  qualified  authors  may 
be  found  among  the  subscribers  of  Internet  med- 
ical mailing  lists  on  anesthesiology  and  critical 
care  medicine.  The.se  professional  discussion 
groups  could  complement  peer-reviewed  pub- 


lications and  conferences  in  professional  infor- 
mation exchange  and  continuing  medical  edu- 
cation. Implications:  Internet  publishing  is  not 
governed  by  rules  that  assure  certain  basic  qual- 
ity standards.  Methods  for  assessing  these  stan- 
dards are  needed.  We  compared  discussion 
groups  with  medical  journals  and  conferences 
on  anesthesiology  and  critical  care  medicine  by 
calculating  the  impact  factor  of  their  members 
and  first  authors,  respectively.  Our  study  shows 
that  qualified  authors  may  be  found  in  all  three 
media. 

Cost-Effectiveness  of  Antiseptic-Impreg- 
nated Central  Venous  Catheters  for  the  Pre- 
vention of  Catheter-Related  Bloodstream  In- 
fection— Veensira  DL,  Saint  S.  Sullivan  SD. 
JAMA  1999  Aug  1 1;282(6):554-560. 

CONTEXT:  A  recent  randomized  controlled 
trial  and  meta-analysis  indicated  that  central  ve- 
nous catheters  impregnated  with  an  antiseptic 
combination  of  chlorhexidine  and  silver  sulfa- 
diazine are  efficacious  in  reducing  the  incidence 
of  catheter-related  bloodstream  infection  (CR- 
BSI);  however,  the  ultimate  clinical  and  eco- 
nomic consequences  of  their  use  have  not  been 
formally  evaluated.  OBJECTIVE:  To  estimate 
the  incremental  clinical  and  econoinic  outcomes 
associated  with  the  use  of  antiseptic-impreg- 
nated vs  standard  catheters.  DESIGN:  Decision 
analytic  model  using  data  from  randomized  con- 
trolled trials,  meta-analyses,  and  case-control 
studies,  as  well  as  safety  data  from  the  US  Food 
and  Drug  Administration.  SETTING  AND  PA- 
TIENTS: A  hypothetical  cohort  of  hospitalized 
patients  at  high  risk  for  catheter-related  infec- 
tions (eg.  patients  in  intensive  care  units,  im- 
munosuppressed  patients,  and  patients  receiv- 
ing total  parenteral  nutrition)  requiring  use  of  a 
central  venous  catheter.  INTERVENTION: 
Short-term  use  (2-10  days)  of  chlorhexidine- 
silver  sulfadiazine-impregnated  multilumen 
central  venous  catheters  and  nonimpregnated 
catheters.  MAIN  OUTCOME  MEASURES:  Ex- 
pected incidence  of  CR-BSI  and  death  attribut- 
able to  antiseptic-impregnated  and  standard 
catheter  use;  direct  medical  costs  for  both  types 
of  catheters.  RESULTS:  In  the  base-ca.se  anal- 
ysis, use  of  antiseptic-impregnated  catheters  re- 
sulted in  a  decrease  in  the  incidence  of  CR-BSI 
of  2.2%  (5.2%  for  standard  vs  3.0%-  for  anti- 
septic-impregnated catheters),  a  decrease  in  the 
incidence  of  death  of  0,33%  (0,78%.  for  stan- 
dard vs  0,45%  for  anti.septic-impregnated),  and 
a  decrease  in  costs  of  $196  per  catheter  used 
($532  for  standard  vs  $3.36  for  antiseptic-im- 
pregnated). The  decrease  in  CR-BSI  ranged  from 
1.2%  to  3.4%,  the  decrease  in  death  ranged 
from  0.09%  to  0.78%,  and  the  costs  saved  ranged 
from  $68  to  $391  in  a  multivariate  sensitivity 
analysis.  CONCLUSION:  Our  analyses  suggest 
that  use  of  chlorhexidine-silver  sulfadiazine- 
impregnated  central  venous  catheters  in  patients 
at  high  risk  for  catheter-related  infections  re- 


1441) 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Innovative  Research. 


met  A  Bad  Way  To  start  Your  ^ 


Go  ahead.  Think  about  making  a  fresh  start.  At  a  place  where  you  can  get  the 
support  and  better  resources  you've  always  deserved.  Best  of  all,  you  don't  have 
to  travel  too  far  to  discover  it.  Because  the  most  powerful  tools  to  develop  yout 
career.. .are  in  the  Midwest.  At  Rush-Pre.sbyterian-St.  Luke's  Medical  Center  in 
Chicago.  Currently,  we  are  seeking  the  following  professionals: 

RESPIRATORY  CARE  PM  SHIFT  SUPERVISOR 

(3:00p.m.-U  :00p.m.) 

You  must  have  at  least  5  years  of  clinicai  experience,  RRT  or  eligible,  Illinois 
licensure,  and  excellent  verbal  and  written  communication  skills,  as  well  as 
basic  desk  top  computer  skills. 

CRTT  or  RRT  RESPIRATORY  THERAPIST 

(7:OOp.m.-7:OOa.m.  shift) 

Requires  the  ability  to  suggest  the  most  appropriate  respiratory  care  to  patients 
of  all  ages.  Individuals  must  be  able  to  interpret  arterial  blood  gas  values,  pet- 
form  ECO  and  basic  spirometry. 

Interested  candidates  please  ft>rwafd  resume  to:  Rush-Presbyterian-St.  Luke's 
Medical  Center,  Dept.  CW-RSP,  729  South  Paulina  Street,  Room  125, 
Chicago,  IL  60612.  Fax:  312-942-3212.  Or  visit  our  Web  site  at: 
www.rush.edu    EOE  M/F/O/V. 


Rush-Presbyterian- 

St.  Luke's  Medical  Center 

(D  RUSH    I    Rush  System  for  Health 


BUYER'S  GUIDE 


Online 


The  1999  Buyer's  Guide  of 
Cardiorespiratory  Care 
Equipment  &  Supplies  is 
also  available  on  the 
Internet.  Visit  the  AARC 
b  site  at  www.aarc.org 
select  Buyer's  Guide 
from  the  main  menu. 


Circle  103  on  product  info  card 


duces  the  incidence  of  CR-BSl  and  death  and 
provides  significant  saving  in  costs.  Use  of  these 
catheters  should  be  considered  as  part  of  a  com- 
prehensive nosocomial  infection  control  pro- 
gram. 

A  Comparison  of  Standard  Cardiopulmo- 
nary Resuscitation  and  Active  Compression- 
Decompression  Resuscitation  for  Out-of- 
Hospital  Cardiac  Arrest.  Frencli  Active 
Compression-Decompression  Cardiopulmo- 
nary Resuscitation  Study  Group — Plaisance 
P,  Luric  KG.  Vicaut  E.  Adnet  F,  Petit  JL.  Epain 
D,  et  al.  N  Engl  J  Med  1999  Aug  19:341(8): 
569-575. 

BACKGROUND:  We  previously  observed  that 
short-term  survival  after  out-of-hospital  cardiac 
arrest  was  greater  with  active  compression-de- 
compression cardiopulmonary  resuscitation 
(CPR)  than  with  standard  CPR.  In  the  current 
study,  we  assessed  the  effects  of  the  active  com- 
pression-decompression method  on  one-year 
survival.  METHODS:  Patients  who  had  cardiac 
arrest  in  the  Paris  metropolitan  area  or  in  Thi- 
onville,  France,  more  than  80  percent  of  whom 
had  asystole,  were  assigned  to  receive  either 
standard  CPR  (377  patients)  or  active  compres- 
sion-decompression CPR  (373  patients)  accord- 
ing to  whether  their  arrest  occurred  on  an  even 
or  odd  day  of  the  month,  respectively.  The  pri- 


mary end  point  was  survival  at  one  year.  The 
rate  of  survival  to  hospital  discharge  without 
neurologic  impairment  and  the  neurologic  out- 
come were  secondary  end  points.  RESULTS: 
Both  the  rale  of  hospital  discharge  without  neu- 
rologic impairment  (6  percent  vs.  2  percent. 
p=0.01)  and  the  one-year  survival  rate  (5  per- 
cent vs.  2  percent.  p=().03)  were  significantly 
higher  among  patients  who  received  active  com- 
pression-decompression CPR  than  among  those 
who  received  standard  CPR.  All  patients  who 
survived  to  one  year  had  cardiac  arrests  that 
were  witnessed.  Nine  of  17  one-year  survivors 
in  the  active  compression-decompression  group 
and  2  of  7  in  the  standard  group,  respectively, 
initially  had  asystole  or  pulseless  electrical  ac- 
tivity. In  12  of  the  17  survivors  who  had  re- 
ceived active  compression-decompression  CPR. 
neurologic  status  returned  to  base  line,  as  com- 
pared with  3  of  7  survivors  who  had  received 
standard  CPR  (p=0.34).  CONCLUSIONS:  Ac- 
tive compression-decompression  CPR  per- 
formed during  advanced  life  support  signifi- 
cantly improved  long-term  survival  rates  among 
patients  who  had  cardiac  arrest  outside  the  hos- 
pital. 

The  Sequence  of  Withdrawing  Life-Sustain- 
ing Treatment  from  Patients — Asch  DA. 
Faber-Langendoen  K.  Shea  JA.  Christakis  NA. 
Am  J  Med  1999  Aug:l07(2):  153-156. 


PURPOSE:  To  describe  the  observed  sequence 
of  withdrawal  of  eight  different  forms  of  life- 
sustaining  treatment  and  to  determine  whether 
aspects  of  those  treatments  determine  the  order 
of  withdrawal.  SUBJECTS  AND  METHODS: 
We  observed  21 1  consecutive  patients  dying  in 
four  midwestern  US  hospitals  from  whom  at 
least  one  of  eight  specific  life-sustaining  treat- 
ments was  or  could  have  been  withdrawn.  We 
used  a  parametric  statistical  technique  to  ex- 
plain the  order  of  withdrawal  based  on  selected 
characteristics  of  the  forms  of  life  support,  in- 
cluding cost,  scarcity,  and  discomfort.  RE- 
SULTS: The  eight  forms  of  life  support  were 
withdrawn  in  a  distinct  sequence.  From  earliest 
to  latest,  the  order  was  blood  products,  hemo- 
dialysis, vasopressors,  mechanical  ventilation, 
total  parenteral  nutrition,  antibiotics,  intrave- 
nous fluids,  and  tube  feedings  (p  <0.000l ).  The 
sequence  was  almost  identical  to  that  observed 
in  a  previous  study  based  on  hypothetical  sce- 
narios. Forms  of  life  support  thai  were  perceived 
as  more  artificial,  scarce,  or  expensive  were 
withdrawn  earlier.  CONCLUSION:  The  pref- 
erence for  withdraw  ing  some  forms  of  life-sus- 
taining treatments  more  than  others  is  associ- 
ated with  intrinsic  characteristics  of  these 
treatments.  Once  the  decision  has  been  inade  to 
forgo  life-sustaining  treatment,  the  process  re- 
mains complex  and  appears  to  target  many  dif- 
ferent goals  simultaneously. 


Respiratory  Care  •  December  1999  Vol  44  No  12 


144! 


Abstracts 


Noninvasive  Ventilation  (review) — Rabatin 
JT,  Gay  PC.  Mayo  Clin  Proc  1999  Aug;74(8): 
817-820. 

Noninvasive  ventilation  refers  to  the  delivery 
of  assisted  ventilatory  support  without  the  use 
of  an  endotracheal  tube.  Noninvasive  positive 
pressure  ventilation  (NPPV)  can  be  delivered 
by  using  a  volume-controlled  ventilator,  a  pres- 
sure-controlled ventilator,  a  bilevel  positive  air- 
way pressure  ventilator,  or  a  continuous  posi- 
tive airway  pressure  device.  During  the  past 
decade,  there  has  been  a  resurgence  in  the  use 
of  noninvasive  ventilation,  fueled  by  advances 
in  technology  and  clinical  trials  evaluating  its 
use.  Several  manufacturers  produce  portable  de- 
vices that  are  simple  to  operate.  This  review 
describes  the  equipment,  techniques,  and  com- 
plications associated  with  NPPV  and  also  the 
indications  for  both  short-term  and  long-term 
applications.  NPPV  clearly  represents  an  im- 
portant addition  to  the  techniques  available  to 
manage  patients  with  respiratory  failure.  Future 
clinical  trials  evaluating  its  many  clinical  ap- 
plications will  help  to  define  populations  of  pa- 
tients most  apt  to  benefit  from  this  type  of  treat- 
ment. 

Oral  Corticosteroids  in  Patients  Admitted  to 
Hospital  with  Exacerbations  of  Chronic  Ob- 
structive Pulmonary  Disease:  A  Prospective 
Randomised  Controlled  Trial — Davies  L,  An- 
gus RM,  Calverley  PM.  Lancet  1999  Aug 
7;354(9177):456-460. 

BACKGROUND:  The  role  of  oral  corticoste- 
roids in  treating  patients  with  exacerbations  of 
chronic  obstructive  pulmonary  disease  (COPD) 
remains  contentious.  We  assessed  in  a  prospec- 
tive, randomised,  double-blind,  placebo- 
controlled  trial  the  effects  of  oral  corticosteroid 
therapy  in  patients  with  exacerbations  of  COPD 
requiring  hospital  admission.  METHODS:  We 
recruited  patients  with  non-acidotic  exacerba- 
tions of  COPD  who  were  randomly  assigned 
oral  prednisolone  30  mg  once  daily  (n  =  29)  or 
identical  placebo  (n  =  27)  for  14  days,  in  addi- 
tion to  standard  treatment  with  nebulised  bron- 
chodilators,  antibiotics,  and  oxygen.  We  did  spi- 
rometry and  recorded  symptom  scores  daily  in 
inpatients.  Time  to  discharge  and  withdrawals 
were  noted  in  each  group.  We  recalled  patients 
at  6  weeks  to  repeat  spirometry  and  collect  data 
on  subsequent  exacerbations  and  treatment. 
Hospital  stay  was  analysed  by  intention  to  treat 
and  forced  expiratory  volume  in  I  s  (FEV,) 
according  to  protocol.  FINDINGS:  FEV,  after 
bronchodilation  increased  more  rapidly  and  to  a 
greater  extent  in  the  corticosteroid-treated 
group:  percentage  predicted  FEV,  after  bron- 
chodilation rose  from  25.7%  (95%  CI  21.0- 
30.4)  to  32.2%  (27.3-27. 1 )  in  the  placebo  group 
(p<0.000l)  compared  with  28.2%  (23.5-32.9) 
to  41.5%  (35.8-47.2)  in  the  corticosteroid- 
ireated  group  (p<0.0001).  Up  to  day  5  of  hos- 


pital stay,  FEV  I  after  bronchodilation  increased 
by  90  mL  daily  (50.8-129.2)  and  by  30  mL 
daily  (10.4-49.6)  in  the  placebo  group 
(p=0.039).  Hospital  stays  were  shorter  in  the 
corticosteroid-treated  group.  Groups  did  not  dif- 
fer at  6-week  follow-up.  INTERPRETATION: 
These  data  provide  evidence  to  support  the  cur- 
rent practice  of  prescribing  low-dose  oral  cor- 
ticosteroids to  all  patients  with  non-acidotic  ex- 
acerbations of  COPD  requiring  hospital 
admission. 


Acute  Respiratory  Distress  Syndrome  (re- 
view)—WyncoU  DL,  Evans  TW.  Lancet  1999 
Aug7;354(9l77):497-50I. 

Outcome  in  acute  respiratory  distress  syndrome 
(ARDS)  is  influenced  by  a  number  of  factors, 
including  the  nature  of  the  precipitating  condi- 
tion and  the  extent  to  which  multiorgan  failure 
ensues.  Most  studies  of  potential  therapeutic 
interventions  have  been  unsuccessful  due  to  the 
enrollment  of  limited  numbers  of  patients  with 
a  wide  variety  of  pathologies  of  varying  sever- 
ity. Moreover,  the  value  of  initiating  single- 
agent  interventions  at  varying  time  points  in 
what  is  an  evolving  and  complex  inflammatory 
process  must  be  questioned.  Mortality  may 
therefore  represent  an  inappropriate  end-point 
for  clinical  trials,  which  are  increasingly  focus- 
ing on  ventilator-free  days.  Despite  these  un- 
certainties, survival  appears  to  be  improving, 
possibly  due  to  the  application  of  supportive 
techniques  in  a  protocol-driven  fashion  to  pa- 
tients in  whom  the  underlying  condition  has 
been  rigorously  treated. 

Prediction  of  Outcome  in  Intensive  Care  Unit 
Trauma  Patients:  A  Multicenter  Study  of 
Acute  Physiology  and  Chronic  Health  Eval- 
uation (APACHE),  Trauma  and  Injury  Se- 
verity Score  (TRISS),  and  a  24-hour  Inten- 
sive Care  Unit  (ICU)  Point  system — Vassar 
MJ,  Lewis  FR  Jr,  Chambers  JA,  Mullins  RJ, 
O'Brien  PE,  Weigelt  JA,  Hoang  MT,  Holcroft 
JW.  J  Trauma  1999  Aug;47(2):324-329. 

OBJECTIVE:  To  conduct  a  multicenter  study 
to  validate  the  accuracy  of  the  Acute  Physiol- 
ogy and  Chronic  Health  Evaluation  (APACHE) 
II  system,  APACHE  III  system.  Trauma  and 
Injury  Severity  Score  (TRISS)  methodology, 
and  a  24-hour  intensive  care  unit  (ICU)  point 
system  for  prediction  of  mortality  in  ICU  trauma 
patient  admissions.  METHODS:  The  study  pop- 
ulation consisted  of  retrospectively  identified, 
consecutive  ICU  trauma  admissions  (n  =  2,414) 
from  six  Level  I  trauma  centers.  Probabilities 
of  death  were  calculated  by  using  logistic  re- 
gression analysis.  The  predictive  power  of  each 
system  was  evaluated  by  using  decision  matrix 
analysis  to  compare  observed  and  predicted  out- 
comes with  a  decision  criterion  of  0.50  for  risk 
of  hospital  death.  The  Youden  Index  (YI)  was 


used  to  compare  the  proportion  of  patients  cor- 
rectly classified  by  each  system.  Measures  of 
model  calibration  were  based  on  goodness-of- 
fit  testing  (Hosmer-Lemeshow  statistic  less  than 
15.5)  and  model  discrimination  were  based  on 
the  area  under  the  receiver  operating  character- 
istic curve  (AUC).  RESULTS:  Overall, 
APACHE  II  (sensitivity,  38%;  specificity,  99%; 
YI,  37%;  H-L  statistic,  92.6;  AUC,  0.87)  and 
TRISS  (sensitivity,  52%;  specificity,  94%;  YI, 
46%;  H-L  statistic,  228. 1 ;  AUC,  0.82)  were  poor 
predictors  of  aggregate  mortality,  because  they 
did  not  meet  the  acceptable  thresholds  for  both 
model  calibration  and  discrimination.  APACHE 
III  (sensitivity,  60%;  specificity,  98%;  YI,  58%; 
H-L  statistic,  7.0;  AUC,  0.89)  was  comparable 
to  the  24-hour  ICU  point  system  (sensitivity, 
51%;  specificity,  98%;  YI,  50%;  H-L  statistic, 
14.7;  AUC,  0.89)  with  both  systems  showing 
strong  agreement  between  the  observed  and  pre- 
dicted outcomes  based  on  acceptable  thresholds 
for  both  model  calibration  and  discrimination. 
The  APACHE  III  system  significantly  improved 
upon  APACHE  II  for  estimating  risk  of  death 
in  ICU  trauma  patients  (p  <  0.001).  Compared 
with  the  overall  performance,  for  the  subset  of 
patients  with  nonoperative  head  trauma,  the  per- 
centage correctly  classified  was  decreased  to 
46%  for  APACHE  II;  increased  to  71%  for 
APACHE  III  (p  <  0.001  vs.  APACHE  II);  in- 
creased to  59%  for  TRISS;  and  increased  to 
62%  for  24-hour  ICU  points.  For  operative  head 
trauma,  the  percentage  correctly  classified  was 
increased  to  60%  for  APACHE  II;  increased  to 
61%  for  APACHE  III;  decreased  to  43%  for 
TRISS  (p  <  0.004  vs.  APACHE  III);  and  in- 
creased to  54%  for  24-hour  ICU  points.  For 
patients  without  head  injuries,  all  of  the  sys- 
tems were  unreliable  and  considerably  under- 
estimated the  risk  of  death.  The  percentage  of 
nonoperative  and  operative  patients  without 
head  trauma  who  were  correctly  classified  was 
decreased,  respectively,  to  26%  and  30%  for 
APACHE  II;  33%  and  29%  for  APACHE  III; 
33%  and  19%  for  TRISS;  20%  and  23%  for 
24-hour  ICU  points.  CONCLUSION:  For  the 
overall  estimation  of  aggregate  ICU  mortality, 
the  APACHE  III  system  was  the  most  reliable; 
however,  performance  was  most  accurate  for 
subsets  of  patients  with  head  trauma.  The  24- 
hour  ICU  point  system  also  demonstrated  ac- 
ceptable overall  performance  with  improved 
performance  for  patients  with  head  trauma. 
Overall,  APACHE  II  and  TRISS  did  not  meet 
acceptable  thresholds  of  performance.  When  es- 
timating ICU  mortality  for  subsets  of  patients 
without  head  trauma,  none  of  these  systems  had 
an  acceptable  level  of  performance.  Further  mul- 
ticenter studies  aimed  at  developing  better  out- 
come prediction  models  for  patients  without 
head  injuries  are  warranted,  which  would  allow 
trauma  care  providers  to  set  uniform  standards 
forjudging  institutional  performance. 


1442 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Use  of  the  Laryngeal  Mask  Airway  in  Air 
Transport  when  Intubation  Fails — Martin  SE, 
Ochsner  MG,  Jarman  RH.  Agudeio  WE.  Davis 
FE.  J  Trauma  1999  Aug;47(2):352-357. 

BACKGROUND:  A  prospective,  nonrandom- 
ized cohort  study  was  conducted  to  determine 
the  effectiveness  of  the  laryngeal  mask  airway 
(LMA)  for  management  of  the  difficult  airway 
in  patients  requiring  air  transport.  METHODS: 
The  LMA  was  inserted  in  those  patients  who 
could  not  be  .successfully  intubated.  Data  were 
collected  to  evaluate  the  effectiveness  of  the 
LMA  and  to  document  any  complications  at- 
tributed to  its  use.  RESULTS;  Inclusion  criteria 
were  met  in  17  of  the  25  patients  receiving  an 
LMA.  The  device  was  inserted  successfully  in 
16  of  17  of  the  patients  (94%).  In-flight  oxygen 
saturation  ranged  from  97  to  \OOVc.  and  end- 
tidal  carbon  dioxide  ranged  from  24  to  35  mm 
Hg.  At  arrival,  initial  arterial  blood  gas  values 
indicated  adequate  oxygenation  in  all  patients 
and  adequate  ventilation  in  15  of  16  patients 
(94%).  There  was  no  evidence  of  complica- 
tions. CONCLUSION:  Our  patient  data  show 
that  when  conventional  methods  have  failed, 
the  LMA  can  be  safely,  rapidly,  and  effectively 
used  for  temporary  airway  control. 

A  Pathogenic  Triad  in  Chronic  Cough: 
Asthma,  Postnasal  Drip  Syndrome,  and  Gas- 
troesophageal Reflux  Disease — Palombini 
BC.  Villanova  CA.  Araujo  E.  Gastal  OL,  Alt 
DC,  Stolz  DP,  Palombini  CO.  Chest  1999  Aug; 
ll6(2);279-284. 

BACKGROUND:  Coughing  may  be  produced 
by  a  number  of  different  disorders  in  distinct 
anatomic  sites.  Chronic  cough  causes  major 
functional  limitation  in  a  considerable  patient 
population  and  requires  careful  evaluation. 
METHODS:  Seventy-eight  nonsmoking  pa- 
tients of  both  genders  who  complained  of  cough 
for  a  3  weeks  and  had  normal  findings  on  plain 
chest  radiographs  were  studied  prospectively. 
Their  histories  were  obtained,  and  physical  ex- 
aminations were  performed.  The  diagnostic 
workup  included  pulmonary  function  tests,  CT 
of  the  paranasal  sinuses  and  chest,  carbachol 
provocation  test,  fiberoptic  rhinoscopy,  fiber- 
optic bronchoscopy,  and  24-h  esophageal  pH 
monitoring.  The  final  diagnosis  depended  on 
clinical,  radiologic,  and  laboratory  findings;  a 
successful  response  to  therapy  was  required  for 
confirmation.  RESULTS:  The  causes  of  chronic 
cough  were  determined  in  all  patients.  Cough- 
ing was  due  to  a  single  cause  in  30  patients 
(38.5%)  and  multiple  causes  in  48  patients 
(61.5%).  The  five  most  important  causative  fac- 
tors were  a.sthma  (46  patients;  58.9%),  postna- 
sal drip  syndrome  (PNDS;  45  patients;  57.6%), 
gastroesophageal  reflux  disease  (GERD;  32  pa- 
tients; 41.1%).  bronchiectasis  (14  patients; 
17.9%).  and  tracheobronchial  collapse  (II  pa- 
tients; 14.1%).  INTERPRETATION:  Asthma, 


KAISER 


PERMANENTE 


It's  Healthcare  Professional  Like  you 
Who  Help  Earn  Us  Recognition  like  This 


Consumers  named  us  their  overall  health  care  provider  of  choice. 
The  California  EPA  has  applauded  our  environmental  conscious- 
ness. The  Pacific  Business  Group  on  Health  gave  us  a  Blue  Ribbon 
for  our  willingness  to  partner  with  business  to  improve  employee 
health.  How  else  can  we  impact  the  communities  we  serve?  That 
could  be  up  to  you  if  you  join  our  exemplary  team. 

Respiratory  Care  Practitioners 

(FuU-Time,  Part-Time,  and  On-Call) 

For  opportunities  in  California,  please  call 

(800)  331-3976 

Great  healthcare  opportunities  are  now  at  your  fingertips. 
Visit  our  exciting  new  emplo^'meiit  Web  site  at 


^ 
^ 


M/ww.kp.org/johs 


KAISER  PERMANENTE 

California 
EEO/AA  Employer 


Circle  115  on  product  Info  card 
Visit  Booth  750  in  Las  Vegas 


PNDS.  and  GERD,  alone  or  in  combination, 
were  responsible  for  93.6%  of  the  ca.ses  of 
chronic  cough.  The  presence  of  these  three  con- 
ditions was  so  frequent  that  the  expression 
"pathogenic  triad  of  chronic  cough"  should  be 
acknowledged  in  specialized  literature.  It  is  es- 
sential to  consider  pulmonary  and  extrapulmo- 
nary causes  in  order  to  prescribe  a  successful 
specific  therapy  for  chronic  cough. 

Corticosteroids  in  the  Emergency  Depart- 
ment Therapy  of  Acute  Adult  Asthma:  An 
Evidence-Based  Evaluation  (Meta-analysis) — 
Rodrigo  G,  Rodrigo  C.  Chest  1999  Aug;l  16(2): 
285-295. 

OBJECTIVE:  To  review  the  literature  to  deter- 
mine the  benefits  of  corticosteroids  (CCSs)  (oral, 
IM,  IV,  or  inhaled)  in  the  treatment  of  adult 
patients  with  acute  asthma  presenting  at  an 
acute-care  setting.  SEARCH  STRATEGY;  A 
MEDLINE  search  was  conducted  using  the  fol- 
lowing terms:  ( 1 )  Asthma  OR  Wheez,  AND  (2) 
Glucocorticoids  OR  Steroids,  AND  (3)  Acute 
OR  Emerg.  Other  sources  were  the  CURRENT 
CONTENTS  database,  review  articles,  refer- 
ence sections  of  located  studies,  and  a  manual 
search  of  the  top  1 5  journals  for  respiratory  and 
emergency  medicine.  SELECTION  CRITE- 
RIA: Patients  were  selected  for  the  study  by  the 
following  criteria:  (1)  English  language;  (2) 


adult  patients  with  asthma  whose  acute  exacer- 
bations were  the  primary  reason  for  assessment; 
(3)  involvement  in  randomized,  controlled  tri- 
als conducted  in  an  emergency  care  setting;  (4) 
patients  had  participated  in  a  study  investigat- 
ing a  primary  research  question  involving  treat- 
ment with  CCSs;  and  (5)  outcomes  based  on 
results  of  pulmonary  function  tests  and  on  hos- 
pital admission  rates.  RESULTS:  At  the  3-h 
assessment,  only  high  doses  of  inhaled  CCSs 
significantly  improved  pulmonary  function 
compared  with  placebo  (effect  size  [ES|,  0.56; 
95%  confidence  interval  [CI],  0.15  to  0.97).  On 
the  other  hand,  after  receiving  IV  CCSs,  pa- 
tients required  at  least  6  to  24  h  to  show  mod- 
erate but  nonsignificant  improvements  of  pul- 
monary function  (6-h  ES,  0.44  (95%  CI,  -0.01 
to  0.89];  12-hES.0.54[95%Cl, -0.08to  1.17]; 
and  24-h  ES,  0.53  (95%  CI,  -0.39  to  1.45]).  The 
data  from  the  six  studies  that  we  used  to  pool 
information  on  admission  rate  outcome  showed 
a  32%  reduction  in  favor  of  the  use  of  IV  CCSs 
(relative  risk[RR].  0.68  (95%  CI.  0.47  to  0.99]; 
number  needed  to  treat.  12.5  (95%  CI.  7.1  to 
50]).  However,  the  pooled  effect  of  the  three 
high-quality  studies  showed  no  difference  be- 
tween groups  (RR,  1.21;  95%  CL  0.67  to  2.18). 
Oral  CCSs  provided  a  similarly  beneficial  ef- 
fect on  pulmonary  function  when  compared  with 
parenteral  administration  (ES,  -0.14;  95%  CI, 
-0.82  to  0.31).  Finally,  the  results  showed  a 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1443 


Abstracts 


nonsignificant  favorable  trend  toward  improved 
outcome  with  medium  or  high  doses  of  CCSs. 
CONCLUSIONS:  This  evidence-based  evalua- 
tion suggests  that  the  administration  of  paren- 
teral CCSs  to  the  patient  on  arrival  at  the  emer- 
gency department  (ED)  neither  improves  airflow 
obstruction  nor  reduces  the  need  for  hospital- 
ization. Parenteral  CCSs  probably  require  >  6 
to  24  h  to  begin  to  act.  Comprehensible  con- 
clusions about  admission  rates  in  the  ED  setting 
are  difficult  to  make.  At  the  3-h  assessment, 
only  high  doses  of  inhaled  CCSs  (in  one  study) 
significantly  improved  pulmonary  function 
compared  with  placebo.  IV  and  oral  CCSs  ap- 
pear to  have  equivalent  effects,  and  there  is  a 
tendency  toward  improvement  in  pulmonary 
function  with  medium  or  high  doses. 

The  Effect  of  Heliox  in  Acute  Severe  Asth- 
ma: A  Randomized  Controlled  Trial — Kass 
JE,TerreginoCA.  Chest  1999  Aug;l  16(2):296- 
3(X). 

STUDY  OBJECTIVES:  To  evaluate  the  effect 
of  heliox  on  airflow  obstruction  and  dyspnea  in 
patients  with  acute  severe  asthma.  DESIGN:  A 
prospective,  randomized,  controlled  study.  SET- 
TING: A  university  hospital.  PATIENTS: 
Twenty-three  patients  presenting  to  the  emer- 
gency department  with  acute  severe  asthma  were 
randomized  to  receive  70%/30%  heliox  or  30% 
oxygen.  MEASUREMENTS:  Peak  expiratory 
flow  (PEF),  dyspnea  score,  heart  rate,  respira- 
tory rate  (RR),  and  BP  were  measured  at  base- 
line and  20,  120,  240,  360,  and  480  min  after 
starting  the  test  gas.  After  baseline,  the  PEF 
was  measured  by  using  the  gas  that  was  ran- 
domized to  the  treatment  program.  RESULTS: 
In  the  first  20  min,  there  was  a  58.4%  increase 
in  percent  predicted  PEF  (%PEF)  in  the  heliox 
group  (p<O.OOI),  whereas  there  was  only  a 
10.1%  increase  in  %PEF  for  the  oxygen  group 
(p>0. 1 ).  Eighty-two  percent  of  the  heliox  group 
had  >25%  improvement  in  %PEF  at  20  min, 
whereas  only  17%  of  the  oxygen  group  did 
(p<0.01).  The  next  significant  improvement  in 
%PEF  in  the  heliox  group  occurred  at  480  min. 
At  the  end  of  the  study  in  the  heliox  group,  the 
PEF  did  not  significantly  (p>0. 1)  change  im- 
mediately after  the  heliox  was  discontinued 
(270.6  to  264.2  L/min).  In  the  heliox  group  in 
the  first  20  min,  there  was  a  significant  de- 
crea.se  in  dyspnea  score  and  RR  (p<0.05),  but 
there  were  no  further  significant  improvements 
for  the  rest  of  the  study.  In  the  oxygen  group, 
no  variables  significantly  improved  until  360 
min.  CONCLUSION:  Heliox  rapidly  improves 
airflow  obstruction  and  dyspnea  in  patients  with 
acute  severe  asthma  and  may  be  useful  as  a 
therapeutic  bridge  until  the  corticosteroid  effect 
occurs. 


Ambulatory  Oximetry  Monitoring  in  Pa- 
tients with  Severe  COPD:  A  Preliminary 


Study— Pilling  J,  Cutaia  M.  Chest  1999  Aug; 
1I6(2):314-321. 

BACKGROUND:  The  benefits  of  long-term  ox- 
ygen supplementation  in  COPD  patients  with 
hypoxemia  are  well  established.  The  standard 
approach  to  prescribing  oxygen  uses  a  static 
assessinent  of  oxygen  requirements  in  a  hospi- 
tal or  clinic  setting.  The  assumption  behind  this 
approach  is  that  patients  will  maintain  a  "ther- 
apeutic" hemoglobin  oxygen  saturation  (SpOj) 
in  the  outpatient  setting.  We  questioned  the  va- 
lidity of  this  assumption,  and  hypothesized  that 
many  patients  may  demonstrate  significant  ox- 
ygen desaturation  during  normal  activities  of 
daily  living.  STUDY  DESIGN,  METHODS, 
AND  MEASUREMENTS:  We  determined  if 
oxygen  supplementation  maintained  a  therapeu- 
tic Spo,  level  in  patients  with  COPD  (n  =  27), 
using  the  technique  of  ambulatory  oximetry 
monitoring  (AOM).  AOM  consisted  of  using  a 
portable  oximeter  to  monitor  Spo^,  pulse  rate, 
and  patient  activity  while  patients  were  engaged 
in  normal  activities  of  daily  living  over  an  ex- 
tended time  period  (approximately  18  h).  The 
portable  oximeter  collected  and  stored  these  data 
every  15  s  over  the  monitored  time  period.  Each 
AOM  recording  was  manually  scored  for  de- 
saturation  events  and  other  key  variables,  in- 
cluding average  Spoj  over  the  monitoring  pe- 
riod, the  average  number  of  desaturation  events 
per  hour,  and  the  percentage  of  monitored  time 
deleted  secondary  to  artifacts.  SETTING:  Uni- 
versity-affiliated Veterans  Affairs  Medical  Cen- 
ter. PATIENTS:  All  subjects  were  patients  with 
stable  COPD  with  no  recent  history  of  hospi- 
talization or  exacerbation  of  their  lung  disease. 
RESULTS :  This  cohort  of  patients  demonstrated 
a  surprising  frequency  of  desaturation  below 
the  recommended  target  Spo,  value  (90%), 
which  averaged  approximately  25%  of  AOM 
recording  time.  There  was  wide  variability 
among  patients  in  the  percentage  of  time  Spo, 
was  below  the  target  value  (range,  3  to  67%  of 
AOM  recording  time).  Motion  artifact  on  the 
AOM  recordings  was  not  a  major  problem;  an 
average  of  8%  of  the  recording  time  was  de- 
leted secondary  to  artifacts  in  this  patient  co- 
hort. CONCLUSIONS:  The  results  demonstrate 
that  AOM  is  feasible  and  accurate  with  an  ac- 
ceptable level  of  motion  artifact.  These  results 
also  suggest  that  the  standard  approach  for  pre- 
scribing oxygen  may  lead  to  subtherapeutic  Spo^ 
values  in  the  outpatient  setting.  AOM  holds 
promise  as  a  tool  to  monitor  the  adequacy  of 
oxygen  prescriptions  in  the  outpatient  setting  in 
patients  with  lung  disease. 


Cardiopulmonary  Exercise  Testing  As  a 
Screening  Test  for  Perioperative  Manage- 
ment of  Major  Surgery  in  the  Elderly — Older 
P,  Hall  A,  Hader  R,  Chest  1999  Aug;  1 16(2): 
355-362. 


STUDY  OBJECTIVE:  To  develop  an  integrated 
strategy  for  the  identification  and  subsequent 
management  of  high-risk  patients  in  order  to 
reduce  both  morbidity  and  mortality.  DESIGN: 
Prospective  consecutive  series  in  which  all  pa- 
tients underwent  cardiopulmonary  exercise 
(CPX)  testing.  SETTING:  CPX  laboratory  and 
level  3  ICU  and  high-dependency  unit  (HDU) 
of  a  metropolitan  teaching  hospital.  PATIENTS: 
Five  hundred  forty-eight  patients  >60  years  of 
age  (or  younger  with  known  cardiopulmoiiary 
disease)  scheduled  for  major  intra-abdominal 
surgery.  INTERVENTIONS:  The  patients  were 
assigned  to  one  of  three  management  strategies 
(ICU,  HDU,  or  ward)  based  on  the  anaerobic 
threshold  (AT)  and  ECG  evidence  of  myocar- 
dial ischemia  as  determined  by  CPX  testing  that 
was  performed  as  part  of  the  presurgery  eval- 
uation, and  by  the  expected  oxygen  demand 
stress  of  the  surgical  procedure.  RESULTS: 
Overall  mortality  was  3.9%.  Forty-three  per- 
cent of  deaths  were  attributed  to  poor  cardio- 
pulmonary function,  as  detected  preoperatively. 
There  were  no  deaths  related  to  cardiopulmo- 
nary complications  in  any  patient  deemed  fit 
for  major  abdominal  surgery  and  ward  manage- 
ment, as  determined  by  CPX  testing.  CONCLU- 
SIONS: In  elderly  patients  undergoing  major 
intra-abdominal  surgery,  the  AT,  as  determined 
by  CPX  testing,  is  an  excellent  predictor  of 
mortality  from  cardiopulmonary  causes  in  the 
postoperative  period.  Preoperative  screening  us- 
ing CPX  testing  allowed  the  identification  of 
high-risk  patients  and  the  appropriate  selection 
of  perioperative  management. 

Effects  of  Humidification  on  Nasal  Symptoms 
and  Compliance  in  Sleep  Apnea  Patients  Us- 
ing Continuous  Positive  Airway  Pressure — 

Massie  CA,  Hart  RW,  Peralez  K,  Richards  GN. 
Chest  1999  Aug;l  16(2):403-408. 

STUDY  OBJECTIVES:  To  evaluate  the  effects 
of  humidification  on  nasal  symptoms  and  com- 
pliance in  sleep  apnea  patients  using  continu- 
ous positive  airway  pressure  (CPAP).  DESIGN: 
A  randomized,  crossover  design  was  employed. 
SETTING:  The  study  was  conducted  at  two 
suburban  community-based  hospital  sleep  lab- 
oratories. PATIENTS:  Data  were  collected  on 
38  obstructive  sleep  apnea  patients  (mean  age, 
44.1  years)  in  whom  CPAP  was  a  novel  treat- 
ment. INTERVENTIONS:  The  intervenUons 
were  heated  humidity,  cold  passover  huinidity, 
and  a  washout  period  without  humidity.  MEA- 
SUREMENTS AND  RESULTS:  Patients  were 
titrated  with  heated  humidity  or  cold  passover 
humidity  in  the  laboratory  and  subsequently  ini- 
tiated on  humidity.  Objective  compliance,  self- 
report  of  factors  affecting  CPAP  use,  satisfac- 
tion with  CPAP,  feeling  upon  awakening,  and 
daytime  sleepiness  were  assessed  at  the  com- 
pletion of  each  3-week  treatment  period  and  a 
2-week  washout  period.  Outcome  measures 
were  assessed  with  one-way  analysis  of  vari- 


144-1 


RESPIRATORY  CaRE  •  DECEMBER  1999  VOL  44  NO  12 


CaU  1-888-4HEP  CDC 

(1-888-443-7232), 

or  visit:  www.cdc.gov/hepatitis 


t 


CDC 


You'd  Be  Surprised  What  EZTape  Will  Hold... 


Your  Patient's  Comfort  is  Right  Up  Our  Alley! 

When  it  comes  to  securing  endotracheal  tubes,  Blal<e  Medical,  Inc.  spares  no 
details!  Invented  and  patented  by  a  respiratory  therapist,  EZTape  holds 
endotracheal  tubes  in  adult  and  pediatric  patients. 

All  tapes  are  not  made  the  samel  Blake  Medical's  EZTape  is  made  of 
hypoallergenic,  wetproof  tape  with  a  soft  non-adhesive  area  for  the  patient's 
neck.  Because  your  patient's  comfort  is  right  up  our  alley. 

Don't  get  stuck  in  the  gutter  of  tearing  tape.  EZTape's  convenient,  precut 
design  attaches  in  seconds.  And  it's  quality  is  unsurpassed. 

Blake  Medical  strikes  again.  This  time,  no  pins  required. 

For  more  information  or  FREE  samples,  just  call  800/989-4553  or  912/388-8080. 


pQbat  17-S5        9!o\9.         3I79T 


Circle  121  on  product  info  card 


ance  followed  by  Scheffe  post  hoc  compari- 
sons. Significant  main  effects  were  observed 
for  compliance  (F2.37  =  5.2;  p  =  0.008).  sat- 
isfaction with  CPAP  (F2.37  =  4.5;  p  =  0.01). 
and  feeling  refreshed  on  awakening  (F2.37  = 
4.4;  p  =  0.02).  A  significant  decrease  in  day- 
time sleepiness  was  observed  between  baseline 
and  each  of  the  conditions  (F3,37  =  55.5; 
p<0.0001),  but  Epworth  sleepiness  scale  scores 
did  not  differ  between  conditions  (all  p  values 
>0.56).  CPAP  use  with  heated  humidity 
(5.52±2.1  h/night)  was  greater  than  CPAP  use 
without  humidity  (4.93±2.2  h/night;  p  =  0.008). 
Compliance  differences  were  not  observed  be- 
tween CPAP  use  with  cold  pas.sover  humidity 
and  CPAP  use  without  humidity.  Patients  were 
more  satisfied  with  CPAP  when  it  was  used 
with  heated  or  cold  passover  humidity  (p£0.05 ). 
However,  only  heated  humidity  resulted  in  feel- 
ing more  refreshed  on  awakening  (p<0.05).  No 
significant  differences  were  observed  among  the 
three  groups  on  the  global  adverse  side  effect 
score  (F2,37  =  2.5;  p  =  0.09).  Specific  side 
effects  such  as  dry  mouth  or  throat  and  dry  nose 
were  reported  less  frequently  when  CPAP  was 
u,sed  with  heated  humidity  compared  to  CPAP 
use  without  humidity  (p<0.001).  CONCLU- 
SIONS: Compliance  with  CPAP  is  enhanced 
when  heated  humidification  is  employed.  This 
is  likely  due  to  a  reduction  in  side  effects  associ- 


ated with  upper  airway  symptoms  and  a  more 
refreshed  feeling  upon  awakening.  Compliance 
gains  may  be  realized  sixmer  if  patients  are  started 
with  heated  humidity  at  CPAP  initiation. 

The  Prognostic  Significance  of  Passing  a 
Daily  Screen  of  Weaning  Parameters — Ely 

EW.  Baker  AM.  Evans  GW.  Haponik  EF.  In- 
tensive Care  Med  1999  Jun;25(6):58 1-587. 

OBJECTIVE:  While  "weaning  parameters"  are 
commonly  used  to  guide  removal  of  mechani- 
cal ventilation  devices,  little  information  exists 
concerning  their  prognostic  value.  We  evalu- 
ated whether  passing  weaning  parameters  was 
a.ssociated  with  survival.  DESIGN:  A  prospec- 
tively followed  cohort  of  mechanically  venti- 
lated patients.  SETTING:  Medical  and  coro- 
nary adult  intensive  care  units  of  an  806-bed 
medical  center.  PATIENTS:  300  consecutively 
enrolled  mechanically  ventilated  patients.  MEA- 
SUREMENTS AND  RESULTS:  216  patients 
who  passed  a  daily  screen  of  weaning  parame- 
ters were  more  likely  to  be  extubated  success- 
fully (87  vs  30%,  p  =  0.0001),  less  likely  to 
require  ventilation  for  >  21  days  (3  vs  30%, 
p  =  0.(X)01).  and  had  a  higher  survival  to  hos- 
pital discharge  (74  vs  29%,  p  =  0.0001)  than 
84  patients  who  never  passed  the  screen.  The 
overall  accuracy  of  the  daily  screen  for  predict- 


ing successful  extubation  and  in-hospital  sur- 
vival was  82  and  73%,  respectively.  Multivar- 
iate proportional  hazards  analysis  of  time  until 
hospital  death  confirmed  the  beneficial  effect 
of  passing  the  daily  screen  (p  =  0.01)  and  of 
duration  of  mechanical  ventilation  (p  =  0.(X)l ) 
even  after  adjustment  for  differences  in  severity 
of  illness,  age,  race,  gender,  diagnosis,  and  treat- 
ment assignment.  While  liberation  from  me- 
chanical ventilation  was  predictive  of  survival 
at  any  time  during  the  hospital  stay  (p  =  0.(X)1 ), 
the  prognostic  significance  of  the  daily  screen 
for  hospital  survival  was  related  to  how  early 
after  intubation  it  was  passed.  The  difference  in 
survival  between  patients  who  had  passed  and 
tho.se  who  had  not  passed  the  daily  screen  was 
significant  for  1  1/2  weeks  postintubation  but 
progressively  decreased  over  time.  The  average 
time  to  extubation  after  passing  the  daily  screen 
increased  from  3  days  (range  0  to  56),  for  those 
passing  within  5  days  of  intubation,  to  8  days  (0 
to  35).  for  those  passing  after  10  days  of  intu- 
bation (r  =  0.26,  p  =  0.(X)l ).  CONCLUSIONS: 
Passing  a  daily  screen  of  weaning  parameters  is 
an  independent  predictor  of  successful  extuba- 
tion and  survival,  but  its  prognostic  value  de- 
creases over  time.  Time  spent  on  mechanical 
ventilation  after  passing  the  daily  screen  pre- 
sents an  important  opportunity  to  optimize  lib- 
eration from  the  ventilator. 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1445 


mm-'.  ■  .   ji»iii 

ACHIEVERS 


Announcing  an  all-new  television 
series  devoted  to  ACHIEVERS, 

What  makes  an  ACHIEVER? 

ACHIEVERS  take  charge  of 
their  lives. . . they  serve  as 
role  models. . . they  view 
challenges  as  opportunities. . . 
they  take  control  of  their 
health  and  fitness. 

Each  week  on  ACHIEVERS, 
you'll  watch  an  intimate 
portrait  of  a  person  who  is 
winning  the  battle  against 
asthma/allergy.  You'll  take  a 
journey  through  a  personal 
landscape  -  one  marked 
by  stark  honesty,  increased 
awareness  and  renewed  hope. 

So  watch,  be  inspired,  be 
informed,  be  an  ACHIEVER. 

ACHIEVERS  is  brought  to  you  by 


CI^^^^^^  //fsl/ 


® 


For  channel  and  times  in  your  area,  check  youi 
local  listing  or  go  to  http://www.krv-i.com 


KALEIDOSCOPE 


I 


'iV'H.com 


Live  on  the  Web.  24  hrs  a  day. 


Original  Contributions 


Automated  Rotational  Therapy  for  the  Prevention  of  Respiratory 
Complications  during  Mechanical  Ventilation 

Neil  R  Maclntyre  MD,  Michael  Helms  PhD,  Richard  Wunderink  MD,  Gregory  Schmidt  MD,  and 

Steven  A  Sahn  MD 


OBJECTIVE:  Test  the  hypothesis  that  automated  rotational  therapy  reduces  the  incidence  of 
respiratory  complications  associated  with  mechanical  ventilation.  STUDY  DESIGN:  A  prospective, 
randomized,  multicenter  trial.  METHODS:  Intubated  mechanically  ventilated  patients  who  were 
free  of  respiratory  infection  were  eligible.  Patients  were  randomized  to  use  either  a  standard 
intensive  care  unit  bed  or  an  automated  rotational  bed  that  could  turn  the  patient  up  to  32  degrees 
from  the  horizontal  8  times  per  hour.  Patients  were  followed  until  successful  extubation,  death,  or 
the  development  of  a  lower  respiratory  tract  inflammatory  syndrome  (LRIS).  The  development  of 
other  clinically  important  events  (ie,  cardiac,  urinary,  gastrointestinal,  neuropsychiatric)  were  also 
recorded.  RESULTS:  There  was  no  signiflcant  difference  in  the  incidence  of  LRIS  in  the  group  that 
used  automated  rotational  beds  as  compared  to  the  control  group  (17%  vs  26%,  p  =  0.15).  There 
was  a  significantly  lower  incidence  of  urinary  tract  infection  (11%  vs  27%,  p  <  0.05)  in  the  patients 
treated  with  automated  rotational  beds.  Nurses  noted  the  development  of  anxiety  in  8  patients  on 
the  automated  rotational  beds.  No  other  signiflcant  differences  in  the  development  of  other  clinical 
events  were  observed.  CONCLUSION:  In  this  study,  the  automated  lateral  rotational  bed  and  the 
turning  strategy  employed  with  that  bed  showed  no  statistically  signiflcant  advantage  over  standard 
ICU  patient-turning  procedures  in  the  prevention  of  lower  respiratory  tract  inflammation.  [Respir 
Care  1999;44(12):1447-1451]  A^ej  words:  rotational  therapy,  nosocomial  pneumonia,  mechanical  ven- 
tilation, immobility. 


Background 

Mechanically  ventilated  patients  are  at  increased  risk 
for  developing  nosocomial  respiratory  infections.'--'  This 
increased  risk  is  a  consequence  of  generalized  reduced 
host  defenses  in  intensive  care  unit  (ICU)  patients,  expo- 


Neil  R  Maclntyre  MD  and  Michael  Helms  PhD  are  affiliated  with  Re- 
spiratory Care  Services,  Duke  University  Medical  Center,  Durham,  North 
Carolina.  Richard  Wunderink  MD  is  affiliated  with  the  Department  of 
Medicine,  University  of  Tennessee,  Memphis,  Tennessee.  Gregory 
Schmidt  MD  is  affiliated  with  the  Department  of  Medicine,  University  of 
Chicago,  Chicago,  Illinois.  Steven  A  Sahn  MD  is  affiliated  with  the 
Division  of  Pulmonary  and  Critical  Care  Medicine,  Medical  University 
of  South  Carolina.  Charleston,  South  Carolina. 

This  study  was  funded  by  a  grant  from  Support  Systems  International, 
Charleston,  South  Carolina. 

Correspondence:  Neil  R  Maclntyre  MD.  Box  3911.  Duke  University 
Medical  Center,  Durham  NC  27710.  E-mail:  macinOOI@mc.duke.edu. 


sure  to  numerous  bacterial  sources  (eg,  gastrointestinal 
tract,  ventilator  circuit),  and  a  number  of  lung-specific 
factors,  including  impaired  airway  protection,  horizontal 
immobility,  and  the  inability  to  effectively  cough  and  clear 
secretions.  Immobility  and  secretion  clearance  impairment 
are  particularly  important  because  they  lead  to  atelectasis 
and  secretion  pooling,'*-'  two  important  factors  in  the  de- 
velopment of  infection. 

Standard  therapy  to  address  these  lung-specific  issues 
includes  positive  end-expiratory  pressure  and  bronchial 
hygiene  techniques  such  as  suctioning.  Regularly  turning 
the  patient  has  also  been  advocated  as  a  means  of  reducing 
atelectasis  and  helping  move  secretions  out  of  the  distal 
lungs,  thereby  reducing  infection  risk.  However,  data  sup- 
porting these  approaches  largely  come  from  the  surgical 
literature,  where  "stir  up"  regimens  have  been  known  for 
years  to  reduce  postoperative  respiratory  complica- 
tions.'"-'^  Because  of  this,  most  ICU  nursing  procedures 
include  some  form  of  regular  patient  turning.  However, 
the  best  angle  and  frequency  of  turning  in  this  population 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1447 


Automated  Rotational  Therapy 


have  never  been  standardized,  and  the  usual  practice  is  to 
rotate  pillow  placement  every  few  hours."' 

In  the  last  several  years,  specialty  beds  have  become 
available  to  automatically  rotate  patients  several  times  an 
hour  at  angles  up  to  67  degrees  from  the  horizontal.  Sev- 
eral clinical  studies  have  been  performed  on  intubated  pa- 
tients using  rotational  beds  to  assess  the  role  of  these  beds 
in  preventing  nosocomial  pneumonia  and  other  pulmonary 
complications.'^"^-'  These  studies  have  generally  shown 
trends  in  favor  of  automated  rotation,  but  sample  sizes 
have  been  small  and  statistical  significance  has  been  dif- 
ficult to  detect.  However,  a  recent  meta-analysis  of  419 
patients  from  6  such  studies  did  find  a  significant  reduc- 
tion in  respiratory  infections  as  a  consequence  of  auto- 
mated rotation. 2-*  To  further  address  this  issue  we  designed 
a  multicenter,  randomized,  controlled  study  of  intubated 
patients.  Our  hypothesis  was  that  automated  regular  turn- 
ing of  an  intubated,  mechanically  ventilated  patient  would 
result  in  fewer  pulmonary  complications  than  would  stan- 
dard care  on  a  nonrotational  ICU  bed. 


Methods 

The  study  design  was  that  of  a  multicenter  (University 
of  Chicago,  University  of  Tennessee,  Medical  University 
of  South  Carolina,  and  Duke  University),  prospective,  ran- 
domized trial  of  automated  rotational  bed  therapy  versus  stan- 
dard bed  therapy  in  patients  who  were  mechanically  venti- 
lated and  initially  clinically  free  of  respiratory  infection. 

Patients  were  eligible  for  the  study  if  they  were  receiv- 
ing mechanical  ventilatory  support  through  an  endotra- 
cheal tube  and  were  expected  to  continue  to  need  this 
support  for  at  least  24  additional  hours.  They  also  had  to 
have  no  clinical  evidence  of  respiratory  infection  and  no 
infiltrates  visible  on  chest  radiograph  suggestive  of  infec- 
tion. Initial  evaluation  consisted  of  a  medical  history,  phys- 
ical examination,  mechanical  ventilation  parameters,  arte- 
rial blood  gases,  complete  blood  count,  serum  electrolytes, 
blood  urea  nitrogen,  serum  glucose,  and  calculation  of 
acute  physiology  and  chronic  health  evaluation  (APACHE) 
II  score  and  Glasgow  coma  score.  Patients  were  excluded 
if  there  was  a  suspected  spinal  cord  injury,  pregnancy, 
weight  greater  than  350  pounds,  height  less  than  48  inches, 
APACHE  II  score  greater  than  30,  a  need  for  traction,  or 
intracranial  pressure  greater  than  20  mm  Hg. 

Eligible  patients  were  then  randomized  to  use  either  an 
automated. rotational  therapy  bed  (Restcue  Bed,  Support 
Systems  International,  Charleston,  South  Carolina)  or  a 
standard  ICU  bed.  The  goal  of  rotation  was  to  raise  one 
lung  above  the  other  on  a  routine  basis.  This  was  to  be 
accomplished  by  providing  8  rotations  per  hour  through  an 
arc  of  32  degrees  to  the  horizontal  in  both  directions,  24 
hours  per  day.  Investigators  could  modify  this  regimen 


Table  I ,      Clinical  Events  Recorded  Daily 


Pulmonary:  pulmonary  embolism  (positive  ventilation-perfusion  scan 

or  arteriogram),  pneumothorax,  suspected  aspiration 
Cardiovascular:  new  arrhythmias,  hemodynamic  changes  requiring 

change  in  bed  therapy,  cardiopulmonary  arrest,  suspected 

myocardial  infarction 
Neuropsychiatric:  anxiety  requiring  change  in  bed  protocol,  change  in 

intracranial  pressure  above  20  mm  Hg 
Gastrointestinal:  suspected  ileus  (3  of  the  following  criteria:  increased 

residuals  from  enteral  feeding,  absent  bowel  sounds,  abdominal 

distension,  abnormal  abdominal  radiograph),  diarrhea  (one  of  the 

following:  frequent  loose  watery  stools,  cessation  of  enteral  feeding 

due  to  diarrhea) 
Genitourinary:  urinary  tract  infection  with  pyuria  and  greater  than  lO'* 

colony-forming  unit  organisms  on  urine  culture 
Skin:  development  of  pressure  sores 
Nursing:  accidental  disconnects  of  equipment  or  loss  of  vascular  lines, 

endotracheal  tubes,  urinary  catheter,  feeding  tube,  rectal  tube 


according  to  patient  comfort,  nursing  requirements  (eg, 
drainage  tube  management),  or  transport  needs.  Patients 
on  a  standard  ICU  bed  could  be  turned  or  positioned  ac- 
cording to  each  institution's  ICU  standards. 

Patients  were  followed  daily  for  evidence  of  possible 
lower  respiratory  tract  inflammation  as  manifested  by  the 
developinent  of  otherwise  unexplained  temperature  eleva- 
tion (>  1 00°  F),  white  blood  cell  count  elevation  (>  10,000/ 
mm"*),  or  purulent  sputum.  Investigators  were  encouraged 
to  obtain  protected  bronchoscopic  specimens  from  the  re- 
spiratory tract  under  these  circumstances.  Our  study  end 
point  was  the  development  of  lower  respiratory  tract  in- 
flammatory syndrome  (LRIS),  as  defined  by  the  develop- 
ment of  at  least  two  of  the  clinical  criteria  described  above 
and  either  an  abnormal  chest  radiograph  consistent  with 
infection  (read  by  a  radiologist  blinded  to  the  study)  or  a 
protected  bronchoscopic  specimen  brush  culture  that 
grew  >  10"*  colony-forming  units  of  a  potential  pathogen. 
It  was  prospectively  decided  that  patients  who  developed 
LRIS  in  the  first  24  hours  of  study  would  be  considered  to 
have  initiated  the  LRIS  process  before  the  rotational  ther- 
apy could  be  effective  and,  thus,  would  be  eliminated  from 
further  analysis. 

Other  parameters  that  were  assessed  daily  included  pulse, 
blood  pressure,  respiratory  rate,  mechanical  ventilation  re- 
quirement, cardiac  rhythm,  and  other  bacteriologic  culture 
results.  In  addition,  important  clinical  events  (Table  1), 
nursing  observations,  and  the  duration  and  magnitude  of 
rotation  were  recorded  daily. 

This  protocol  was  approved  by  each  center's  institu- 
tional review  board,  and  informed  consent  was  obtained 
prior  to  randomization. 

A  sainple  size  of  98  patients  was  planned  for  an  a  level 
of  0.05  and  a  power  of  80%.  This  was  based  on  an  esti- 
mated 37%  incidence  of  lower  respiratory  tract  inflamma- 


1448 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Automated  Rotational  Therapy 


Table  2.      Demographics  of  the  Study  Population 


Table  3.      Entry  Data  in  the  Study  Population* 


Standard 

Automated 

Standard  ICU 
Bed  (11  =  51) 

Automated 

ICU  Bed 

(«  =  51) 

Rotational  Bed 
(«  =  53) 

Entry  Values 

Rotational 
Bed  («  =  53) 

Age  (years,  mean  ±  SD) 

56.4  ±  17 

56.1  ±  14 

Sex  (%  male) 

39 

38 

Temperature  (°F) 

99.5  ±  0.3 

99,2  ±  0,3 

Primary  diagnosis  (%) 

Systolic  blood  pressure  (mm  Hg) 

126  ±4.2 

125  ±  3,9 

Neurological 

14 

15 

Heart  rate  (beats/min) 

107  ±  3 

106  ±  3 

Shock/sepsis 

8 

16 

Mechanical  tidal  volume  (mL) 

739  ±  18 

772  ±  22 

Gastrointestinal 

6 

6 

Mechanical  rate  (breath.s/min) 

16  ±0.8 

14  ±  0.9 

Acute  respiratory  distress 

syndr 

sme 

12 

10 

PEEP  (cm  H2O) 

2.2  ±  0.5 

2.9  ±  0.5 

Chronic  obstructive  pulmonary 

Jisea,se 

22 

23 

P^o,  (mm  Hg) 

146  ±  14 

130  ±8 

Asthma 

10 

6 

PaO,/FlO, 

301  ±  19 

336  ±  26 

Congestive  heart  failure 

20 

10 

P.,eo,  (mm  Hg) 

43  ±  2.2 

40  ±  1 .9 

Post  arrest 

4 

4 

Glasgow  coma  score 

11.6  ±0.5 

11.2  ±0.5 

Thoracic  surgery 

2 

2 

APACHE  II  score 

16.4  ±  0.7 

16.7  ±  0.9 

Abdominal  surgery 

— 

4 

Hemoglobin 

1 1 .9  ±  0.3 

11.4  ±0.3 

Trauma 

2 

4 

White  blood  cell  count  (X  1000/mm') 
BUN  (mEq/L) 
Albumin  (g/dL) 
Calcium  (mEq/L) 

13.0  ±  1.0 
29.8  ±  4.8 

11.3  ±0.8 

31.4  ±  3.6 

ICU  =  intensive  care  unit. 

3.11  ±0,11 
8.4.')  ±0.11 

2.97  ±0.14 

8.1  ±0.15 

Baseline  chest  radiograph: 

percent  of  patients  with: 

tion  in  mechanically  ventilated  patients  and 

an  expected 

Normal  findings 

56 

56 

60%  reduction  of  this  i 

n  the 

group 

treated  wi 

th  automated 

Interstitial  edema 

23 

15 

rotational  therapy.''' 20 

Analvcp^   pr»n*;i*;tf»rl 

nf  rV 

li-cnnn 

rp    tp*;rino 

hf»t\x/^f^n    th*^ 

Atelectasis 

21 

29 

groups  receiving  automated  rotational  and  standard  ther- 
apy for  the  development  of  LRIS  and  other  clinically  rel- 
evant items.  In  addition,  the  risk  factors  of  Glasgow  coma 
score  and  APACHE  II  score  were  used  to  predict  the  de- 
velopment of  LRIS  in  both  groups  using  stepwise  multi- 
variate analysis. 


*  Means  ±  standard  error. 

ICU  -  intensive  care  unit. 

PEEP  =  positive  end-expiratory  pressure. 

PaOi  =  arterial  oxygen  tension. 

FlOi  -  fraction  of  inspired  oxygen, 

PacOi  -  arterial  carbon  dioxide  tension. 

.APACHE  -  Acute  Physiology  and  Chronic  Health  Evaluation 

BU,\  =  bitxMJ  urea  nitrogen. 


Results 


One  hundred  four  patients  were  entered  into  the  study 
over  a  two-year  period.  The  characteristics  of  the  study 
population  are  given  in  Tables  2  and  3  and  show  that  this 
patient  population  represented  a  moderately  severely  ill 
group  requiring  extended  mechanical  ventilation.  The 
groups  receiving  automated  rotational  or  standard  therapy 
appear  well  matched. 

In  the  group  receiving  automated  rotational  therapy,  lat- 
eral rotation  was  provided  on  94%  of  patient-days.  The 
mean  angles  of  rotation  were  approximately  20  degrees  to 
the  horizontal  to  both  left  and  right.  There  were  an  average 
of  137  complete  rotations  per  day  in  the  automated  rota- 
tional therapy  group. 

One  patient  developed  LRIS  in  the  first  24  hours  and 
was  not  considered  in  the  subsequent  analyses.  The  devel- 
opment of  LRIS  in  the  remaining  patients  is  summarized 
in  Table  4,  and  although  the  incidence  of  LRIS  was  slightly 


lower  in  the  rotational  therapy  group,  it  did  not  reach 
statistical  significance  (chi-square  =  1.87.  p  =  0.15).  Of 
interest  is  that  14  of  the  22  patients  with  LRIS  were  among 
the  40  patients  who  had  an  APACHE  11  score  >  20  or  a 
Glascow  coma  score  <  9  (ie,  64%  of  the  LRIS  developed 
in  39%  of  the  patients).  However,  though  higher  APACHE 
II  scores  were  significantly  associated  with  the  develop- 
ment of  LRIS  in  the  multivariate  analysis  (p  <  0.01),  the 
effect  of  automated  rotation  did  not  reach  statistical  sig- 
nificance (p  =  0.13). 

Two  other  clinical  events  were  found  to  be  significantly 
different  between  the  two  groups  (Table  5).  First,  in  the 
automated  rotational  therapy  group  there  were  significantly 
fewer  urinary  tract  infections  (11%  vs  27%,  p  <  0.05). 
Second,  in  8  of  the  patients  in  the  automated  rotational 
therapy  group,  nurses  observed  anxiety  that  necessitated 
adjustment  of  rotational  strategy,  and  one  of  these  patients 
was  subsequently  taken  off  the  bed.  No  other  significant 
differences  between  the  groups  were  noted. 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1449 


Automated  Rotational  Therapy 


Table  4.      Development  of  Lower  Respiratory  Tract  Innammatory 

Syndrome  in  Patients  Using  Automated  Rotational  Bed  vs 
Standard  Intensive  Care  Unit  Bed 


Automated  Rotational 
Bed  {n  =  52) 

Standard  Intensive 

Care  Unit  Bed 

(n  =  51) 

Time  in  study  (days) 

6.5 

5.3 

Number  (and  %) 

9(17.3) 

13(25,5) 

developing  LRIS 

Number  developing  LRIS 

5/19 

9/21 

among  those  with 

APACHE  II  score  >  20 

or  Glasgow  coma  score 

<9 

!:hronic  Health  Evaluation. 

APACHE  =  Acute  Physiology  and  ( 

LRIS  =  lower  respiratory  tract  inflammatory  syndrome 

Table  5.      Nonrespiratory  Clinical  Events  in  Patients  Using 

Automated  Rotational  Bed  vs  Standard  Intensive  Care 
Unit  Bed 


Automated 

Standard 

Rotational 

ICU  Bed 

Bed  (n  =  52) 

(n  =  51) 

% 

% 

Pulmonary 

Suspected  embolism 

2 

2 

Aspiration 

2 

2 

Cardiovascular 

Cardiac  arrest 

11 

2 

New  arrhythmias 

23 

14 

Suspected  myocardial  i 

infarct 

2 

6 

Gastrointestinal 

Ileus 

2 

0 

Diarrhea 

15 

4 

Urinary  tract  infection 

11 

27 

Development  of  pressure 

sores 

9 

6 

Nursing 

Loss  of  endotracheal  tube 

10 

2 

Loss  of  vascular  lines 

2 

0 

Loss  of  other  tubes 

0 

0 

Death 

15 

14 

•p  <  0.05. 

ICU  =  intensive  care  unit. 

esis  on  the  established  concept  that  patient-turning  reduces 
atelectasis  and  secretion  pooling/-'''  which  are  two  risk 
factors  for  LRIS  in  immobilized,  mechanically  ventilated 
patients.  Our  major  finding,  however,  was  that  there  was 
not  a  statistically  significant  difference  in  the  incidence  of 
LRIS  in  patients  receiving  automated  rotational  therapy. 
Several  comments  regarding  study  design  and  data  inter- 
pretation are  in  order. 

First,  we  chose  LRIS  as  our  end  point  rather  than  re- 
stricting ourselves  to  only  bacteriologically-proven  pneu- 
monia. We  did  this  recognizing  that  LRIS  includes  pneu- 
monia as  well  as  atelectasis  and  tracheobronchitis. 
However,  because  these  other  causes  of  LRIS  usually  re- 
quire equally  aggressive  medical  workups  and  often  sim- 
ilar empiric  therapy,  and  because  most  of  these  other  causes 
would  also  be  expected  to  respond  to  rotational  therapy, 
our  LRIS  criteria  gave  us  a  potentially  larger  number  of 
measurable  "events." 

Second,  our  sample  size  may  have  been  inadequate  to 
avoid  a  j3  error  based  on  our  prestudy  estimates.  As  noted 
previously,  we  planned  a  sample  size  of  98  based  on  an 
expected  control-population  LRIS  incidence  of  37%  and 
an  expected  reduction  in  LRIS  of  60%.  What  we  found, 
however,  was  a  25.5%  LRIS  incidence  in  the  control  group 
and  a  3 1  %  reduction  in  the  treated  group.  Using  the  same 
significance  levels  as  planned,  a  sample  size  of  several 
times  this  would  be  needed  for  significance  to  be  found 
with  these  percentages. 

Third,  the  particular  rotational  bed  used  in  this  study 
employs  "smart  pillow"  technology  (ie,  computer- 
controlled  inflation  of  different  sections  of  the  low  pres- 
sure mattress)  instead  of  bed  frame  tilting.  This  allows 
patients  to  have  a  single  bed  that  provides  pressure-sore 
reduction^'  along  with  automated  rotation.  However,  ro- 
tation angle  is  less  than  with  frame  tilt  beds  (32  degrees  to 
the  horizontal  with  our  system  vs  up  to  67  degrees  to  the 
horizontal  with  some  of  the  studies  in  the  previously-men- 
tioned meta-analysis24).  It  is  conceivable  that  a  steeper 
turning  angle  may  have  had  a  greater  impact  on  the  pre- 
vention of  LRIS. 

Finally,  our  protocol  allowed  standard  ICU  care  to  be 
given  to  control  patients.  This  often  included  turning  every 
several  hours  with  pillows.  Thus  our  study  compared  only 
automated  frequent  turning  with  "standard"  turning  regi- 
mens. Therefore,  it  is  not  possible  to  extrapolate  our  re- 
sults to  turning  of  any  type. 


Discussion 


Other  Consequences  of  Automated  Rotation 


Respiratory  Issues 

Our  hypothesis  was  that  automated  rotational  therapy 
would  reduce  the  incidence  of  LRIS  in  patients  requiring 
prolonged  mechanical  ventilation.  We  based  this  hypoth- 


There  were  significantly  fewer  urinary  tract  infections 
in  patients  receiving  automated  rotational  therapy.  This  is 
a  finding  observed  by  others'^  and  may  reflect  the  bene- 
ficial effects  of  less  urine  stasis  in  the  bladder. 


1450 


RESPIRATORY  CaRE  •  DECEMBER  1999  VoL  44  No  12 


Automated  Rotational  Therapy 


Anxiety  was  noted  more  frequently  in  patients  receiving 
automated  rotational  therapy.  Anxiety  may  not  be  a  sur- 
prising development  in  some  patients  receiving  frequent 
rotation,  especially  those  who  are  "between"  clear  con- 
sciousness and  unconsciousness.  It  should  be  noted,  how- 
ever, that  despite  this  anxiety,  only  one  patient  had  to  be 
removed  from  the  study.  Moreover,  automated  rotational 
therapy  was  not  associated  with  an  increased  incidence  of 
serious  "stress"  complications  such  as  cardiac  arrhythmia 
or  myocardial  infarct  (see  Table  5). 

Conclusions 

Regular  patient-turning  has  long  been  known  to  be  im- 
portant in  reducing  respiratory  complications  in  immobile 
patients.  Because  of  this,  automated  rotational  therapy  beds 
have  been  developed  to  provide  such  turning  in  immobile 
patients  who  require  prolonged  mechanical  ventilation. 
However,  outcome  data  supporting  the  use  of  these  sys- 
tems are  very  limited,  and  important  questions  remain  re- 
garding cost  benefit,  optimal  patient  selection,  and  optimal 
turning  regimen.  In  our  study  population,  the  automated 
lateral  rotational  bed  design  and  the  turning  strategy  em- 
ployed with  that  bed  were  no  more  effective  in  preventing 
lower  respiratory  tract  inflammation  than  were  standard 
ICU  patient-turning  procedures. 

ACKNOWLEDGMENTS 

The  authors  are  grateful  to  Ms  Janet  Johns  and  Ms  Theresa  Stewan  for 
their  secretarial  expertise. 

REFERENCES 

1 .  Tapson  VF.  Fulkerson  WJ.  Infectious  complications  of  inechanical 
ventilation.  In:  Fulkerson  WM.  Maclntyre  NR.  editors.  Problems  in 
respiratory  care:  complications  of  mechanical  ventilation.  Philadel- 
phia: JB  Lippincott:  1991;4(1):100-1 17. 

2.  Craven  DE.  Kunches  IM.  Kilinski  V,  Lichtenberg  DA.  Make  BJ, 
McCabe  WR.  Risk  factors  for  pneumonia  and  fatality  in  patients 
receiving  continuous  mechanical  ventilation.  Am  Rev  Respir  Dis 
1986;13.3(5):792-796. 

3.  Niederman  MS,  Ferranti  RD.  Ziegler  A.  Merrill  WW,  Reynolds  HY. 
Respiratory  infections  complicating  long-term  tracheostomy:  the  im- 
plication of  persistent  Gram-negative  tracheobronchial  colonization. 
Chest  1984:85(1  ):39-44. 

4.  Blair  E,  Hickham  JB.  The  effect  of  change  in  body  position  on  lung 
volume  and  intrapulmonary  gas  mixing  in  normal  subjects.  J  Clin 
Invest  I9.'55;34:383-389. 

5.  Kaneko  K.  Milic  Emili  J.  Dolovich  MB  Dawson  A,  Bates  DV. 
Regional  distribution  of  ventilation  and  perfusion  as  a  function  of 
body  position.  J  Appl  Physiol  1966:21(3):767-777. 

6.  Zack  MB,  Pontoppidan  H,  Kazemi  H.  The  effect  of  lateral  positions 
on  gas  exchange  in  pulmonary  disease:  a  prospective  evaluation.  Am 
Rev  Respir  Dis  1974;1 10(l):49-5.'i. 


7.  Wong  JW.  Keens  TG.  Wannamaker  EM.  Douglas  PT.  Crozier  N. 
Levison  H.  Aspin  N.  Effects  of  gravity  on  tracheal  mucus  transport 
rates  in  normal  subjects  and  in  patients  with  cystic  fibrosis.  Pediat- 
rics 1977:60(2):  1 46- l.'i2. 

8.  Blake  J.  On  the  movement  of  mucus  in  the  lung.  J  Biomech  1975; 
8(3-4):  1 79-1 90. 

9.  Reines  HD,  Harris  RC.  Pulmonary  complications  of  acute  spinal 
cord  injuries.  Neurosurgery  1987:21(2):193-196. 

10.  Powers  JH.  The  abuse  of  rest  as  the  therapeutic  measure  in  surgery. 
JAMA  1944;125:1079-1083. 

1 1 .  Proceedings  of  the  Sugarloaf  Conference  on  the  Scientific  Basis  on 
In-Hospital  Respiratory  Therapy.  Atlanta,  Georgia.  Am  Rev  Respir 
Dis  1980:122(5  Pt  2):1-I61. 

1 2.  Celli  BR,  Rodriguez  KS,  Snider  GL.  A  controlled  trial  of  intermittent 
positive  pressure  breathing,  incentive  spirometry,  and  deep  breathing 
exercises  in  preventing  pulmonary  complications  after  abdominal 
surgery.  Am  Rev  Respir  Dis  1984:1.W(1  ):12-15. 

13.  Olson  EV.  Johnson  BJ,  Thompson  LF.  The  hazards  of  immobility, 
1967.  Am  J  Nurs  1990:90(3):43^8. 

14.  Kigin  CM.  Chest  physical  therapy  for  the  postoperative  or  traumatic 
injury  patient.  Phys  Ther  I981;6I(I2):I724-1736. 

15.  Gamsu  G,  Singer  MM.  Vincent  HH.  Berry  S.  Nadel  JA.  Postoper- 
ative impairment  of  mucous  transport  in  the  lung.  Am  Rev  Respir 
Dis  1976:1 14(4):67.3-679. 

16.  Standards  of  nursing  care  for  adult  patients  with  pulmonary  dysfunc- 
tion. American  Thoracic  Society.  Medical  Section  of  the  American 
Lung  A.ssociation.  Am  Rev  Respir  Dis  1991;144(l):231-236. 

17.  Kelley  RE.  Vibulsresth  S.  Bell  L.  Duncan  RC.  Evaluation  of  kinetic 
therapy  in  the  prevention  of  complications  of  prolonged  bed  rest 
secondary  to  stroke.  Stroke  1987;I8(3):638-642. 

18.  Summer  WR.  Curry  P.  Haponik  EF.  Nelson  S,  Elston  R.  Continuous 
mechanical  turning  of  intensive  care  unit  patients  shortens  length  of 
stay  in  some  diagnostic-related  groups.  J  Crit  Care  1989:4:45-53. 

19.  Fink  MP.  Helsmoortel  CM.  Stein  KL,  Lee  PC.  Cohn  SM.  The  effi- 
cacy of  an  oscillating  bed  in  the  prevention  of  lower  respiratory  tract 
infection  in  critically  ill  victims  of  blunt  trauma:  a  prospective  study. 
Chest  1990:97(I):132-137. 

20.  Gentilello  L,  Thompson  DA,  Tonnesen  AS.  Hernandez  D,  Kapadia 
AS,  Allen  SJ,  et  al.  Effect  of  a  rotating  bed  on  the  incidence  of 
pulmonary  complications  in  critically  ill  patients.  Crit  Care  Med 
I988;16(8):783-786. 

21.  Clemmer  TP,  Green  S,  Ziegler  B,  Wallace  CJ,  Menlove  R,  Orme  JF, 
et  al.  Effectiveness  of  the  kinetic  treatment  table  for  preventing  and 
treating  pulmonary  complications  in  severely  head-injured  patients, 
Crit  Care  Med  1990:18(6):614-617. 

22.  Brackett  TO,  Condon  N.  Comparison  of  the  wedge  turning  frame 
and  kinetic  treatment  table  in  the  acute  care  of  spinal  cord  injury 
patients.  Surg  Neurol  1984:22(l):53-56. 

23.  de  Boisblanc  BP,  Castro  M,  Everret  B,  Grender  J,  Walker  CD, 
Sumner  WR,  Effect  of  air-supported,  continuous,  postural  oscillation 
on  the  risk  of  early  ICU  pneumonia  in  non-traumatic  critical  illness. 
Chest  1993:103(5):  1543-1. 547. 

24.  Choi  SC,  Nelson  LD,  Kinetic  therapy  in  critically  ill  patients:  com- 
bined results  based  on  meta-analysis,  J  Crit  Care  1992;7:57-62. 

25.  Feldman  DL,  Sepka  RS,  Klitzman  B,  Tissue  oxygenation  and  blood 
flow  on  specialized  and  conventional  hospital  beds.  Ann  Plas  Surg 
1993;30(5):441- 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1451 


Medical  and  Psychiatric  Predictors  of  Airway  Reactivity 

Karen  B  Schmaling  PhD,  Niloofar  Afari  PhD,  Scott  Bamhart  MD,  and  Dedra  S  Buchwald  MD 


BACKGROUND:  The  diagnosis  of  asthma  is  made  difficult  by  the  overlap  of  asthma  symptoms 
with  those  of  other  disorders  and  by  the  limitations  of  the  specificity  of  bronchoprovocation  tests 
and  symptoms.  The  purpose  of  this  study  was  to  assess  the  utility  of  demographic,  medical,  and 
psychiatric  variables  in  predicting  airway  hyperresponsiveness  defined  by  methacholine  inhalation 
challenge  (MIC)  test  results  among  patients  presumed  to  have  asthma.  METHODS:  Sixty-eight 
patients  with  clinical  diagnoses  of  asthma  underwent  MIC  and  provided  information  about  demo- 
graphic variables,  psychiatric  symptoms,  and  medical  utilization  related  to  asthma.  Logistic  re- 
gression was  used  to  identify  clinical  predictors  of  positive  versus  negative  MIC  results.  RESULTS: 
Negative  MIC  results  were  associated  with  being  older,  being  a  life-long  nonsmoker,  having  better 
air  flow,  and  with  having  full  or  subsyndromal  symptoms  of  social  phobia.  Among  persons  with 
clinical  diagnoses  of  mild-to-moderate  asthma,  31%  had  negative  MIC  tests.  Anxiety  symptoms 
related  to  social  circumstances  were  powerful  predictors  of  the  absence  of  bronchial  hyperrespon- 
siveness. CONCLUSIONS:  Anxiety  symptoms  may  be  mislabeled  as  a  respiratory  condition,  lead- 
ing to  unnecessary  medical  utilization.  [Respir  Care  1999;44(12):1452-1457]  A^ey  words:  asthma, 
anxiety,  methacholine,  lyronchial  provocation  tests. 


Background 

Asthma  has  been  defined  as  "a  disease  characterized  by 
an  increased  responsiveness  of  the  trachea  and  bronchi  to 
various  stimuli  and  manifested  by  a  widespread  narrowing 
of  the  airways  that  changes  in  severity  either  spontane- 
ously or  as  a  result  of  therapy,"'  and  as  "a  chronic  inflam- 
matory disorder  of  the  airways"  associated  with  recurrent 
episodes  of  wheezing  and  other  respiratory  symptoms,  vari- 
able airflow  obstruction  that  is  often  reversible,  and  bron- 
chial hyperresponsiveness  to  a  variety  of  stimuli.-  These 
definitions  indicate  that  airway  hyperresponsiveness  is  a 
fundamental  feature  of  asthma.  The  clinical  diagnosis  of 
asthma  is  based  on  the  presence  of  relevant  symptoms. 


Karen  B  Schmaling  PhD  is  affihated  with  the  Departmenl  of  Psychiatry 
and  Behavioral  Sciences,  University  ol' Washington;  Niloofar  Afari  PhD. 
Scott  Bamhart  MD.  and  Dedra  S  Buchwald  MD  are  affiliated  with  the 
Department  of  Medicine.  University  of  Washington;  Scott  Bamhart  MD 
is  affiliated  with  the  Medical  Director's  Office,  Harborview  Medical 
Center;  Dedra  S  Buchwald  MD  is  affiliated  with  the  Chronic  Fatigue 
Clinic.  Harborview  Medical  Center.  Seattle,  Washington. 

This  research  was  supported  by  National  Institutes  of  Health  award 
R01MH5I647. 

Correspondence:  Karen  B  Schmaling  PhD.  Department  of  Psychiatry  and 
Behavioral  Sciences,  Box  .^.S6.S6().  University  of  Washington.  Seattle 
WA  98195.  E-mail:  karens@u. washington.edu. 


either  currently  or  by  history,  and  significant  airflow  lim- 
itation and  reversibility.''  In  the  absence  of  airflow  limita- 
tion based  on  spirometry  testing,  the  presence  of  airway 
responsiveness  to  nonspecific  bronchoprovocation  chal- 
lenge tests  can  be  used  to  confirm  a  diagnosis  of  asthma. 

The  diagnosis  of  asthma  is  made  difficult  by  several 
factors,  among  them,  the  overlap  of  some  asthma  symp- 
toms with  those  of  anxiety  disorders  in  general  and  panic 
disorder  in  particular,"'"'  reliance  on  historical  reports  of 
symptoms,  changing  airway  responsiveness  with  age,''  and 
the  common  dilemma  of  "asthma-like"  symptoms  in  the 
context  of  normal  or  near-normal  airflow  limitation  on 
spirometry  testing.  Anxiety  disorders  such  as  panic  disor- 
der, phobias,  and  generalized  anxiety  disorder  are  com- 
monly associated  with  dyspnea,  chest  tightness,  and  smoth- 
ering sensations.  There  appears  to  be  a  high  comorbidity 
between  asthma  and  panic  disorder  and  other  anxiety  dis- 
orders.'*''*' Furthermore,  asthma  patients  with  panic  disor- 
der report  significantly  higher  levels  of  perceived  breath- 
lessness  after  an  inhalation  challenge  test  than  those  without 
panic  disorder.'^  Bronchodilator  use  also  has  been  shown 
to  be  more  strongly  related  to  perceived  discomfort  rather 
than  actual  bronchoconstriction.'"  In  clinical  settings,  how- 
ever, asthma  patients  are  not  routinely  assessed  for  coex- 
isting psychiatric  symptoms. 

Aside  from  the  issue  of  concomitant  anxiety  disorders, 
a  confirmation  of  airway  hyperresponsiveness  in  tho,se  with 


1452 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Medical  and  Psychiatric  Predictors  of  Airway  Reactivity 


normal  airflow  is  necessary  for  the  diagnosis  of  asthma. - 
Although  bronchoprovocation  testing  such  as  methacho- 
line  inhalation  challenge  (MIC)  may  provide  a  relatively 
safe  and  readily  available  laboratory  test  for  confirming 
the  presence  or  absence  of  asthma,"  several  problems 
plague  the  interpretation  of  its  results.  First,  MIC  is  not 
highly  specific.  It  yields  a  relatively  high  incidence  of 
false  positive  diagnoses  in  people  with  other  disease  pro- 
cesses.'2'''  For  example,  in  a  study  of  atopic  patients,  47% 
of  atopic  but  nonasthmatic  patients  had  a  reactive  response 
to  methacholine  that  could  be  indicative  of  asthma." 

Second,  MIC  may  lack  diagnostic  sensitivity.  There  is 
significant  overlap  of  the  airway  responsiveness  of  normal 
persons  and  patients  with  asthma.'-'^  Therefore,  it  is  dif- 
ficult to  establish  a  cutoff  or  concentration  of  methacho- 
line that  would  reliably  distinguish  persons  with  asthma 
from  those  without  asthma."'-'^  Employing  an  often  used 
cutoff,  one  study  reported  100%  specificity,  but  only  55% 
sensitivity  in  distinguishing  asthma  patients  and  normal 
controls."*  Most  studies  of  methacholine  have  focused  on 
hyperreactivity  to  any  concentration,  including  the  largest 
concentration  of  methacholine  delivered  in  any  standard- 
ized procedure.  Given  that  normal  subjects  may  exhibit  a 
significant  response  at  concentrations  >  8  mg/mL  of  metha- 
choline, hyperresponsiveness  to  concentrations  of  <  8 
mg/mL  has  been  recommended  as  indicative  of  asthma.^ 
In  sum,  the  presence  of  any  hyperresponsiveness  to  bron- 
choprovocation tests  cannot  be  considered  definitive  in  the 
diagnosis  of  asthma. 

Previous  studies  have  found  that  age,''-''^  smoking  his- 
tory,''' atopy, '^■-"  and  symptoms  of  asthma-"-'  are  associ- 
ated with  bronchial  hyperreactivity.  The  purpose  of  the 
present  study  was  to  identify  additional  predictors  of  air- 
way reactivity  as  measured  by  MIC,  using  sociodemo- 
graphic,  medical,  and  psychiatric  variables. 


Methods 


Participants 


All  patients  age  18  to  60  with  International  Classifica- 
tion of  Diseases  (ICD-9)  billing  codes  for  asthma  (code 
category  493)  seen  at  a  community  practice  group  special- 
izing in  asthma  and  allergy  care  between  approximately 
May  1995  and  May  1997  were  recruited  to  participate  in 
the  study.  A  recruitment  letter  was  sent  to  1,677  poten- 
tially eligible  participants.  The  data  included  in  the  present 
report  were  gathered  in  the  initial  evaluation  phase  of  a 
longitudinal  study  on  the  association  between  stress  and 
asthma  among  patients  with  asthma  who  were  cohabiting 
with  a  significant  other.  The  study  was  approved  by  the 
Human  Subjects  Review  Committee  at  the  authors'  insti- 
tution. 


After  obtaining  informed  consent,  participants  were  in- 
terviewed regarding  descriptive  information  and  medical 
utilization  in  the  previous  18  months,  completed  a  struc- 
tured psychiatric  interview,  and  underwent  an  MIC.  The 
information  obtained  by  interview  included  age,  gender, 
ethnicity,  relationship  status,  partner's  medical  diagnoses 
and  smoking  history,  years  of  education,  income,  current 
medications  and  history  of  steroid  use  in  the  previous  two 
years,  other  medical  diagnoses,  and  the  number  of  office, 
emergency  department,  and  inpatient  admissions  for  asthma 
in  the  previous  18  months.  In  addition,  patients'  clinic 
charts  were  reviewed  for  relevant  medical  information  and 
to  verify  medical  utilization  reports.  Subjects  were  paid  for 
completing  the  study. 

Methacholine  Inhalation  Challenge 

A  standard  laboratory  protocol  was  used  for  the  MIC 
with  all  participants.  Care  was  taken  to  follow  established 
procedures.22-23  At  the  time  of  the  MIC,  all  participants 
were  free  of  upper  respiratory  tract  infections  and  had  not 
used  oral  corticosteroids  for  at  least  two  weeks  prior  to  the 
study.  Participants  were  instructed  to  withhold  several  med- 
ications prior  to  testing:  inhaled  bronchodilators  for  the 
day  of  testing;  inhaled  steroids  for  12  hours;  and  antihis- 
tamines for  72  hours.  None  of  the  participants  used  cro- 
molyn sodium  or  theophylline,  so  they  were  not  instructed 
regarding  those  medications.  In  addition,  participants  were 
asked  to  refrain  from  consuming  chocolate  or  caffeinated 
beverages  for  12  hours  prior  to  the  MIC.  In  order  to  fa- 
cilitate the  scheduling  of  appointments,  all  MIC  tests  were 
performed  in  the  afternoon. 

On  the  day  of  testing,  baseline  pulmonary  function  tests 
were  performed  based  on  the  recommendations  of  the 
American  Thoracic  Society,--*  using  a  KoKo  spirometer 
(PDS  Instrumentation,  Louisville,  Colorado)  interfaced 
with  a  microcomputer.  Throughout  the  testing  session  par- 
ticipants were  monitored  for  adequacy  of  effort  and  were 
believed  to  be  compliant  with  all  procedures.  A  patient 
would  not  undergo  the  MIC  unless  his  or  her  forced  ex- 
piratory volume  in  the  first  second  (FEV,)  was  >  65%  of 
predicted.--''  After  baseline  spirometry,  patients  received 
first  saline  and  then  methacholine  from  a  nebulizer  (PARI 
LC  Jet+,  PARI  Respiratory  Equipment,  Midlothian,  Vir- 
ginia) that  attached  directly  to  the  KoKo  spirometer  and 
allowed  an  intermittent  delivery  time  of  0.6  seconds.  Metha- 
choline solutions  were  prepared  according  to  the  manu- 
facturer's package  insert-*  and  administered  in  sequential- 
ly-increasing concentrations  (0.025.  0.25.  2.5,  5.0.  10.0, 
and  25.0  mg/mL).  The  inhalation  procedure  for  the  saline 
and  methacholine  solutions  included  5  slow  breaths  from 
functional  residual  capacity  to  inspiratory  capacity  without 
breath-holding.  A  saline  FEV,  was  obtained  after  1.5  min- 
utes; post-MIC  FEV,  also  was  obtained  1.5  minutes  after 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1453 


Medical  and  Psychiatric  Predictors  of  Airway  Reactivity 


each  methacholine  inhalation  step.-''  To  ensure  reproduc- 
ibility of  pulmonary  function  test  measurements,  each  pa- 
tient performed  3  acceptable  forced  expiratory  maneuvers. 
The  highest  of  the  consistent  FEV,  attempts  was  recorded 
for  saline  and  each  methacholine  step.  MIC  testing  was 
terminated  when  a  20%  drop  from  the  saline  baseline  FEV, 
was  detected  or  the  final  methacholine  concentration  was 
reached.  If  necessary,  an  inhaled  bronchodilator  was  ad- 
ministered at  the  termination  of  testing  to  reverse  the  ef- 
fects of  the  methacholine. 

Bronchial  responsiveness  was  expressed  as  PC20  (the 
concentration  of  methacholine  causing  a  20%  drop  in  FEV, 
from  the  saline  baseline).  This  value  was  obtained  by  a 
linear  interpolation  formula  of  the  last  two  data  points.^ 
An  individual  MIC  test  was  categorized  as  negative  if  its 
PC20  was  >  8  mg/mL  or  as  positive  if  its  PCjo  was  s  8 
mg/mL.'' 

Diagnostic  Interview  Schedule  III-R 

The  Diagnostic  Interview  Schedule  (DIS)  is  a  structured 
interview^*'  with  good  psychometric  characteristics,-' 
which  assesses  26  Diagnostic  and  Statistical  Manual  III- 
R^"  psychiatric  disorders.  Professional  interviewers  (PhDs 
in  clinical  psychology)  administered  a  computer-assisted 
version  of  the  DIS  in  the  present  study.  Somatization, 
panic,  generalized  anxiety,  agoraphobia,  social  and  simple 
phobias,  and  major  depressive  disorders  were  assessed. 
The  DIS  is  especially  useful  in  assessing  psychiatric  dis- 
orders in  nonpsychiatric  samples.  For  each  disorder,  the 
patient  is  categorized  as  having  none,  a  current,  or  a  life- 
time diagnosis.  In  the  present  study,  a  subsyndromal  cat- 
egory was  utilized  for  each  diagnosis  to  account  for  pa- 
tients who  reported  partial  symptoms  and  significant 
distress  without  meeting  the  criteria  for  a  full  diagnosis.  In 
the  Diagnostic  and  Statistical  Manual  III-R,  such  subsyn- 
dromal diagnoses  would  be  noted  with  a  "Not  Otherwise 
Specified"  label  such  as  "Anxiety  Disorder  Not  Otherwise 
Specified." 

Chart  Review 

Clinic  charts  were  reviewed  for  relevant  medical  infor- 
mation, including  ICD-9  diagnosis  (493.0  extrinsic  asthma, 
or  493.1  intrinsic  asthma),  allergy  status  (negative  or  pos- 
itive skin  test  results),  current  immunotherapy,  and  smok- 
ing history  (lifetime  nonsmoker  or  history  of  <  10  pack- 
years  of  tobacco  use  prior  to  5  years  before  the  study).  The 
ratio  of  the  forced  expiratory  volume  in  the  first  second  to 
the  forced  vital  capacity  (FEV|/FVC)  from  the  last  spi- 
rometry was  noted  as  a  measure  of  airflow  limitation.  In 
addition,  the  chart  review  was  used  to  verify  the  type  and 
quantity  of  prescribed  asthma  medications,  and  the  num- 


ber of  office,  emergency  department,  and  inpatient  visits 
for  the  18  months  prior  to  study  enrollment. 

Data  Analyses 

Descriptive  statistics  were  utilized  to  characterize  the 
patients.  A  square  root  transformation  was  used  to  achieve 
homogeneity  of  error  variance  for  the  office,  emergency 
department,  and  inpatient  visit  variables.""  The  transformed 
scores  were  used  in  all  analyses.  We  used  /  tests  for  inde- 
pendent samples  and  chi-square  or  Fisher's  exact  test  to 
test  for  differences  between  groups  with  positive  and  neg- 
ative MICs,  for  continuous  and  categorical  variables,  re- 
spectively. A  modified  Bonferroni  test  was  used  to  correct 
for  the  number  of  comparisons. ''-  Using  this  method,  the  a 
priori  level  of  significance  was  set  at  p  <  0.003;  all  tests 
were  two-sided.  Logistic  regression  was  used  to  identify 
predictors  of  positive  and  negative  MICs.  Demographic 
and  medical  variables  associated  with  bronchial  reactivity 
in  previous  studies  were  entered  into  the  equation  as  a 
block.  These  variables  included  gender,  age,  diagnosis  (ex- 
trinsic vs  intrinsic  asthma),  FEV,/FVC,  type  of  asthma 
medications  (beta  agonists  with  or  without  inhaled  ste- 
roids), and  smoking  history.  Additional  variables  found  to 
differentiate  participants  with  positive  and  negative  metha- 
choline tests  as  empirically  identified  by  the  univariate 
analyses  in  the  present  study  were  then  entered  in  a  hier- 
archical fashion.  Data  management  and  analysis  were  con- 
ducted with  SPSS  for  Windows,  release  7.0  (SPSS,  Chi- 
cago, Illinois). 

Results 

Sample  Characterization 

We  received  responses  from  627  of  1,677  potentially 
eligible  participants  with  ICD-9  billing  codes  for  asthma 
(493);  it  is  not  known  how  many  of  those  who  did  not 
respond  to  the  recruitment  letter  had  exclusionary  condi- 
tions for  the  study.  Three  hundred  three  persons  responded 
by  postcard  that  they  were  uninterested  in  the  study,  and 
these  people  were  not  contacted  further,  so  it  is  not  known 
if  they  were  uninterested  or  were  self-selecting  because 
they  did  not  meet  study  criteria.  Two  hundred  fifty-six 
potential  participants  were  disqualified  for  the  following 
reasons:  not  married  or  cohabiting  with  a  significant  other 
of  the  opposite  sex  (22%);  current  smoker  or  had  a  >  10 
pack-year  smoking  history  or  partner  who  smoked  (9%); 
oral  steroid  use  for  longer  than  30  treatment  days  in  the 
previous  two  years  (4%);  medical  exclusions  such  as 
chronic  obstructive  pulmonary  disease,  obesity,  pregnancy, 
or  other  poorly  controlled  medical  conditions  (12%);  part- 
ner had  poorly  controlled  medical  conditions  (5%);  older 
than  60  (3%);  not  interested  in  participating  after  hearing 


1454 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Medical  and  Psychiatric  Predictors  of  Airway  Reactivity 


Table  I .      Patient  Characteristics 


Positive  MIC 

Negative  MIC 

P 
value 

Demographic  Variables 

Age 

36.7  ± 

10.0 

39.4  ± 

11.6 

0.33 

Female  (%) 

66.0 

61.9 

0.75 

White  (%) 

87.2 

71.4 

0.17 

Education  (%  >  16  years) 

72.3 

76.2 

0.74 

Income  (%  >  $50,000/year) 

59.6 

60.0* 

0.97 

Medical  Variables 

ICD-9  Code  (%)* 

0.09 

493.0  Extrinsic  asthma 

71.2 

28.8 

— 

493.1  Intrinsic  a.sthma 

0 

100.0 

— 

FEV,/FVC 

0.78  ±  0.08 

0.83  ± 

0.08 

0.02 

Medication  type  (%)* 

0.11 

beta-agonists  alone 

31.9 

52.4 

— 

beta-agonists  and  inhaled 

68.1 

47.6 

— 

steroids 

Current  immunotherapy  (%) 

23.4 

28.6 

0.65 

Smoking  history  (%  ex- 

29.8 

9.5 

0.12 

smokers) 

Utilization  Variables 

Office  visits 

4.26  ± 

3.18 

4.25  ± 

2.97t 

1.00 

Emergency  department  visits 

0.23  ± 

.73 

0.05  ± 

.22t 

0.12 

Inpatient  visits 

0.04  ± 

.20 

0.05  ± 

.22t 

0.90 

Number  of  asthma 

3.51  ± 

1.38 

3.62  ± 

1.12 

0.75 

medications 

Psychiatric  Variables  {%) 

Somatization 

12.8 

23.8 

0.25 

Panic  disorder 

I9.I 

14.3 

0.74 

Generalized  anxiety 

8.5 

9.5 

1.00 

Simple  phobia 

21.3 

38.1 

0.15 

Agoraphobia 

10.6 

14.3 

0.70 

Social  phobia  2.1 

23.8 

0.009 

Major  depression 

44.7 

47.6 

0.82 

MIC  =  melhacholine  inhalation  cliallenge. 

ICD  =  International  Classification  of  Diseases. 

FEVt/FVC  =  ratio  of  forced  expiratory  volume  in  the  first  second  to  forced  vital  capacity. 

*This  p  value  is  associated  with  the  results  of  a  2  X  2  test  with  two  levels  to  the  medical 

variable  and  to  the  MIC  results  (positive  versus  negative). 

in  =  20. 

Note:  Positive  MIC  In  -  47)  and  negative  MIC  in  -  21)  unless  otherwise  specified.  Medical 

visits  were  for  the  1 8  months  prior  to  study  enrollment.  Number  of  asthma  medications  were 

recorded  at  the  time  of  enrollment.  Positive  psychiatric  variables  include  patients  with 

subsyndromal.  current,  or  lifetime  diagnoses. 


more  about  the  study  (41%);  in  another  research  study 
(2%);  or  FEV,  <  65%  of  predicted  before  the  MIC  so  it 
could  not  be  performed  (2%).  There  were  no  psychiatric 
exclusion  criteria.  Sixty-eight  participants  qualified  for  and 
completed  the  study  protocol. 

Table  1  shows  the  proportions,  or  means  and  standard 
deviations,  for  all  variables,  by  patient  group  (negative  and 
positive  MIC).  Forty-seven  patients  (68%)  were  catego- 
rized as  having  positive  MIC  tests.  Other  data  from  some 
of  the  participants  with  positive  MIC  tests  in  this  study 
have  been  reported  elsewhere.'*''-"* 


Most  patients  were  white  women  averaging  nearly  38 
years  of  age,  had  college  or  post-graduate  education,  and 
had  household  income  of  s  $50,000.  There  were  no  sig- 
nificant differences  between  patients  with  positive  and  neg- 
ative MIC  on  demographic  variables. 

Medical,  Utilization,  and  Psycliiatric  Characteristics 

The  results  of  several  group  comparisons  were  interest- 
ing, but  no  group  comparisons  attained  statistical  signifi- 
cance, in  part  because  of  the  conservative  approach  to 
significance  testing  used  in  this  study.  Patients  with  a  pos- 
itive MIC  tended  to  have  lower  FEV/FVC  ratios  than 
patients  with  a  negative  MIC.  Interestingly,  all  of  the  pa- 
tients with  an  ICD-9  diagnosis  of  intrinsic  asthma  (493.1) 
were  found  to  have  a  negative  MIC.  A  larger  proportion  of 
positive  MIC  patients  had  a  history  of  smoking,  in  com- 
parison with  negative  MIC  patients. 

Psychiatric  diagnoses  were  common  in  the  study  sam- 
ple; nearly  46%  of  the  patients  met  criteria  for  a  depressive 
disorder.  Social  phobia  was  about  1 0  times  more  common 
among  patients  with  negative  MICs  than  among  patients 
with  positive  MICs. 

Predictors  of  Reactivity  to  Methaclioline 

Logistic  regression  was  used  to  identify  demographic, 
medical,  and  psychiatric  predictors  of  airway  reactivity  to 
methacholine.  Gender,  age,  diagnosis  (extrinsic  vs  intrin- 
sic asthma),  FEV|/FVC,  type  of  asthma  medications  (beta 
agonists  with  or  without  inhaled  steroids),  and  smoking 
history  were  entered  into  the  equation  as  a  block.  This 
model  was  significant  (chi-square  [6]  =  22.15,  p  =  0.001) 
and  correctly  classified  76%  of  the  cases  (94%  of  patients 
with  positive  MIC  and  38%  of  patients  with  negative  MIC). 
Older  age,  not  having  a  smoking  history,  and  better  FEVj/ 
FVC  were  significant  predictors  of  negative  MIC  results 
(odds  ratios  all  >  5.6). 

Next,  social  phobia  was  entered  into  the  above  model  in 
a  hierarchical  fashion.  The  addition  of  social  phobia  sig- 
nificantly improved  the  model  (improvement  chi-square 
[1]  =  12.82,  p  =  0.0003)  and  case  classification:  82.4%  of 
the  cases  were  correctly  classified  (96%  of  patients  with 
positive  MICs  and  52%  of  cases  with  negative  MICs). 
With  the  addition  of  social  phobia,  smoking  history  was  no 
longer  a  significant  predictor  of  MIC  results. 

Discussion 

In  a  sample  of  patients  from  an  asthma  clinic,  the  present 
study  found  that  21  of  68  (31%)  did  not  have  bronchial 
hyperresponsiveness  based  on  the  commonly  accepted  stan- 
dard of  a  PC20  >  8  mg/mL.  In  addition  there  was  an 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1455 


Medical  and  Psychiatric  Predictors  of  Airway  Reactivity 


association  between  anxiety  symptoms  and  the  absence  of 
bronchial  hyperresponsiveness. 

In  the  present  study  subsyndromal  and  fully  syndromal 
social  phobia  tended  to  differentiate  patients  with  positive 
and  negative  MIC  tests,  and  significantly  predicted  the 
presence  of  negative  MIC  results.  The  central  feature  of 
social  phobia  is  fear  of  social  situations  in  which  the  per- 
son may  face  scrutiny  and  fear  of  behaving  in  a  humiliat- 
ing or  embarrassing  manner."'  Anticipation  of  or  exposure 
to  the  phobic  stimulus  or  situation  often  provokes  an  im- 
mediate anxiety  response  such  as  feeling  panicky,  sweat- 
ing, tachycardia,  and  difficulty  breathing. 

The  diagnosis  of  social  phobia  is  made  when  the  anxiety 
and  resulting  avoidance  behavior  interfere  with  occupa- 
tional or  social  functioning.  At  times,  individuals  force 
themselves  to  endure  the  social  phobia  situation,  which  is 
experienced  with  intense  anxiety.  The  symptoms  are  sim- 
ilar to  those  experienced  by  asthmatics.  The  physician 
faced  with  diagnosing  asthma  may  wish  to  query  if  the 
respiratory  symptoms  occur  in  special  circumstances,  such 
as  social  settings.  Social  phobia  should  be  a  diagnosis  to 
consider  when  treating  patients  who  describe  unexplained 
respiratory  symptom  "flares'"  but  whose  MIC  results  are 
unknown  or  negative.  Careful  attention  to  documenting 
reversible  airflow  obstruction  is  essential  to  the  diagnosis 
of  asthma.--* 

Consistent  with  previous  research,'*^  a  remote  history  of 
smoking  was  initially  associated  with  negative  MIC.  but 
this  effect  was  abolished  with  the  addition  of  social  phobia 
to  the  prediction  equation.  Social  self-presentation  factors 
are  strongly  involved  in  the  decision  to  use  tobacco  and 
other  drugs:  tobacco  is  used  when  the  smoker  wishes  to  be 
perceived  as  sociable. ^"^  Ex-smokers  no  longer  have  smok- 
ing as  a  social  coping  strategy,  which  may  lead  to  in- 
creased social  discomfort.  The  results  of  the  present  study 
would  be  consistent  with  this  pattern  of  behavior. 

The  main  limitations  of  the  present  study  were  two-fold. 
First,  our  exclusive  measure  of  bronchial  hyperresponsive- 
ness was  based  on  a  decrease  in  FEV,  measured  via  spi- 
rometry. In  some  patients,  however,  spirometry  may  not 
be  sensitive  or  specific  enough  to  detect  a  response  to 
bronchoprovocation  agents. ^^  In  such  cases  other  measure- 
ments such  as  airway  resistance  and  specific  conductance 
may  suggest  a  positive  methacholine  response  in  specific 
airways.  Although  these  parameters  may  be  used  in  clin- 
ical settings  when  diagnosing  an  individual  patient  strongly 
suspected  of  having  asthma,  the  literature  is  mixed  on 
which  spirometry  values  are  associated  with  response  in 
various  particular  airways. ^^-^^  Thus,  these  results  could  be 
open  to  interpretation  and  not  standard  across  groups  of 
patients.  In  addition,  FEV,  has  been  recommended  as  the 
primary  variable  to  be  monitored  during  MIC,-'  and  the 
American  Thoracic  Society  guidelines  for  the  evaluation 
of  asthma  patients'  strongly  recommend  the  use  of  PC,,) 


(based  on  a  decreases  in  FEV,)  as  the  accepted  standard  in 
the  measurement  of  airway  responsiveness  when  airflow 
limitation  is  absent. 

The  second  limitation  was  the  potential  for  respondent 
bias.  Our  sample  may  have  been  biased  by  the  use  of 
patients  presenting  to  a  specialty  clinic,  the  narrow  inclu- 
sion of  patients  with  a  clinical  diagnosis  of  asthma  in  the 
mild  to  moderate  range  of  severity,  and  of  patients  with  an 
interest  in  the  association  between  stress  and  asthma,  which 
may  explain  the  seemingly  high  prevalence  of  significant 
psychiatric  symptoms  among  this  sample.  However,  anx- 
iety and  depression  are  common  among  persons  with 
asthma.  For  example,  one  report  found  that  23%  of  93 
patients  with  asthma  had  panic  attacks.''  The  inclusion  of 
subjects  with  a  restricted  range  of  asthma  severity  makes 
more  difficult  the  identification  of  relatively  subtle  differ- 
ences between  patients  with  positive  and  negative  MIC 
tests.  Studying  samples  with  wider  ranges  of  asthma  se- 
verity would  increase  statistical  power  to  detect  differ- 
ences. On  the  other  hand,  it  is  often  patients  such  as  those 
in  the  present  study  for  whom  the  diagnosis  of  asthma 
requires  scrutiny  and  confirmation  to  avoid  costs  and  ad- 
verse effects  associated  with  asthma  medications  if  they 
prove  to  be  unnecessary. 

Conclusions 

Nearly  one  third  of  a  sample  of  patients  with  presumed 
asthma  did  not  exhibit  bronchial  hyperresponsiveness  when 
challenged  with  methacholine.  Clinically  important  phobia 
symptoms  to  social  situations  were  associated  with  the 
absence  of  bronchial  hyperresponsiveness.  Anxiety-related 
symptoms  may  result  in  a  misdiagnosis  of  asthma.  Addi- 
tional studies  are  recommended  to  characterize  the  poten- 
tial for  anxiety  symptoms  to  masquerade  as  asthma. 

REFERENCES 

1 .  American  Thoracic  Society  Committee  on  Diagnostic  Standards.  Def- 
inition and  classification  of  chronic  bronchitis,  asthma,  and  pulino- 
nary  emphysema.  Am  Rev  Re.spir  Dis  1962;85:762-768. 

2.  National  Heart,  Lung  and  Blood  Institute.  Guidelines  for  the  diag- 
nosis and  management  of  asthma.  Jul.  1997:  NIH  Publication  Nuin- 
ber  97-4051. 

3.  American  Thoracic  Society  Medical  Section  of  the  American  Lung 
Association.  Guidelines  for  the  evaluation  of  impairment/disability 
in  patients  with  asthma.  Am  Rev  Respir  Dis  199.^:I47(4):1()56- 
1061. 

4.  Schinaling  KB,  Bell,  J.  Asthma  and  panic  disorder.  Arch  Fam  Med 
1997;6(1):20-2.1 

5.  Yellowlees  PM.  Alpcrs  JH.  Bowden  JJ,  Bryant  GD.  Ruffin  RE. 
Psychiatric  inorbidity  in  patients  with  chronic  airflow  obstruction. 
Med  J  Aust  1987;146(6):.30.5-.307. 

6.  Hopp  RJ.  Bewtra  A.  Nair  NM,  Townley  RG.  The  effect  of  age 
on  methacholine  response.  J  Allergy  Clin  Immunol  1985:76(4): 
609-61,3. 

7.  Carr  RE,  Lehrer  PM.  Rausch  LL.  Hochron  SM.  Anxiety  sensitivity 
and  panic  attacks  in  an  asthmatic  population.  Behav  Res  Ther  1994: 
32(4):41 1-418. 


1456 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Medical  and  Psychiatric  Predictors  of  Airway  Reactivity 


II 


13 


8.  Spinhoven  P.  Ros  M,  Westgeest  A.  Van  der  Does  AJW.  The  pre- 
valence of  respiratory  disorders  in  panic  disorder,  major  depres- 
sive disorder  and  V-code  patients.  Behav  Res  Ther  I994;32(6): 
647-649, 

9.  Van  Peski-Oosterbaan  AS,  Spinhoven  P,  Van  der  Does  AJW,  Wil- 
lems  LNA,  Sterk  PJ.  Is  there  a  specific  relationship  between  asthma 
and  panic  disorder?  Behav  Res  Ther  l996;34(4):333-34(). 

10.  Nouwen  A.  Freeston  MH,  Cournoyer  I,  Deschesnes  F,  Boulet  LP. 
Perceived  symptoms  and  discomfort  during  induced  bronchospasm: 
the  role  of  temporal  adaptation  and  anxiety.  Behav  Res  Ther  1994; 
32{6):623-628. 

Pratler  MR,  Irwin  RS.  Is  the  demonstration  of  bronchial  hyperreac- 
tivity the  sine  qua  non  for  diagnosing  symptomatic  bronchial  asthma? 
Allergy  Proc  l989;10(5):32.3-327. 

Greenspon  LW.  Gracely  E.  A  discriminant  analysis  applied  to  inelha- 
choline  bronchoprovocation  testing  improves  classification  of 
patients  as  normal,  asthma,  or  COPD.  Chest  1 992;  1 02(5):  1 4 1 9- 1 42.5. 
Muller  BA.  Leick  CA,  Smith  RM.  Suelzer  MT,  Richerson  HB.  Com- 
parisons of  specific  and  nonspecific  bronchoprovocation  in  subjects 
with  asthma,  rhinitis,  and  healthy  subjects.  J  Allergy  Clin  Iminunol 
I993;9I(3):758-772. 

14.  Cockcroft  DW,  Murdock  KY,  Kirby  J,  Hargreave  F.  Prediction  of 
airway  responsiveness  to  allergen  from  skin  sensitivity  to  allergen 
and  airway  responsiveness  to  histamine.  Am  Rev  Respir  Dis  1987; 
I3.5(l):264~267. 

15.  Cockcroft  DW,  Berscheid  BA,  Murdock  KY.  Unimodal  distribution 
of  bronchial  responsiveness  to  inhaled  histamine  in  a  random  human 
population.  Chest  l983;83(5):75l-754. 

16.  Popa  V,  Singleton  J.  Provocation  dose  and  discriminant  analysis  in 
histamine  bronchoprovocation:  are  the  current  predictive  data  satis- 
factory? Chest  l988:94(3):466-475. 

17.  Chhabra  SK,  Gaur  SN,  Khanna  AK.  Clinical  significance  of  non- 
specific bronchial  hyperresponsiveness  in  asthma.  Chest  I989;96(3): 
596-600. 

18.  Eliasson  AH,  Phillips  YY,  Rajagopal  KR.  Howard  RS.  Sensitivity 
and  .specificity  of  bronchial  provocation  testing:  an  evaluation  of 
four  techniques  in  exercise-induced  bronchospasm.  Chest  1992; 
l02(2):347-355. 

19.  O'Connor  GT.  Sparrow  D,  Segal  MR.  Weiss  ST.  Smoking,  atopy 
and  methacholine  airway  responsiveness  among  middle  aged  and 
elderly  inen.  The  Normative  Aging  Study.  Am  Rev  Respir  Dis  1989; 
140(6):  1520-1526. 

20.  Cookson  WOCM,  Musk  AW,  Ryan  G.  Associations  between  asthma 
history,  atopy,  and  non-specific  bronchial  responsiveness  in  young 
adults.  Clin  Allergy  I986;16(5):425^32. 


21.  Pattemore  PK,  Asher  Ml,  Harrison  AC,  Mitchell  EA,  Rea  HH,  Stew- 
art AW,  The  interrelationship  ainong  bronchial  hyperresponsiveness, 
the  diagnosis  of  asthma,  and  asthma  symptoms.  Am  Rev  Respir  Dis 
l990;142(3):549-5.54, 

22.  Subcommitee  on  bronchial  inhalation  challenges.  Guidelines  for  bron- 
chial inhalation  challenges  with  pharmacologic  and  antigenic  agents. 
ATS  News  l980;Spring:l  1-19. 

23.  AARC  Clinical  Practice  Guideline.  Bronchial  provocation.  Respir 
Care  l992;37(8);902-906. 

24.  Standardization  of  spirometry,  1994  update.  American  Thoracic  So- 
ciety. Am  J  Respir  Crit  Care  Med  I995;I52(3):1 107-1 136. 

25.  Crapo  RO,  Morris  AH,  Gardner  RM.  Reference  spirometric  values 
using  techniques  and  equipment  that  meet  ATS  recommendations. 
Am  Rev  Respir  Dis  I981;123(6):6.59-664. 

26.  Package  insert.  Provocholine.  Hoffman-La  Roche  Inc. 

27.  Chai  H,  Farr  RS,  Froehlich  LA,  Mathison  DA,  McLean  JA,  Rosenthal 
RR,  et  al.  Standardization  of  bronchial  inhalation  challenge  proce- 
dures. J  Allergy  Clin  Immunol  1975;56(4):32.3-327. 

28.  Helzer  JE,  Robins  LN.  McEvoy  LT,  Spitznagel  EL,  Stoltzman  RK, 
Farmer  A,  Brockington  IF.  A  comparison  of  clinical  and  diagnostic 
interview  schedule  diagnoses:  physician  reexamination  of  lay-inter- 
viewed cases  in  the  general  population.  Arch  Gen  Psychiatry  1985; 
42(7):657-666. 

29.  Marcus  S,  Robins  LN,  Bucholz  K.  Quick  diagnostic  interview  Sched- 
ule III-R,  Version  1.0.  Washington  University  School  of  Medicine, 
St  Louis,  Missouri,  1988. 

.30.  American  Psychiatric  Association:  Diagnostic  and  statistical  manual 
of  mental  disorders,  3rd  edition  (revised).  Washington  DC:  Ameri- 
can Psychiatric  Association;  1987. 

31.  Kirk  RE.  Experimental  design.  Belmont  CA:  Brooks/Cole;  1968. 

32.  Keppel  G.  Design  and  analysis:  a  researcher's  handbook,  2nd  edi- 
tion. New  Jersey:  Prentice-Hall;  1982. 

33.  Schmaling  KB,  Afari  N,  Barnhart  S,  Buchwald  DB.  The  association 
of  disease  severity,  functional  status,  and  medical  utilization  with 
relationship  satisfaction  among  asthma  patients  with  their  partners. 
J  Clin  Psychol  Med  Settings  1997;4:373-382. 

34.  Afari  N,  Schmaling  KB.  Asthma  patients  and  their  partners:  gender 
differences  in  the  relationship  between  psychological  distress  and 
patient  functioning.  J  Asthma  (2000.  in  press). 

35.  Leary  MR,  Tchividjian  LR,  Kraxberger  BE.  Self-presentation  can  be 
hazardous  to  your  health:  impression  management  and  health  risk. 
Health  Psychol  1 994;  13(6):46 1^70. 

36.  Spector  SL.  Bronchial  inhalation  challenges  with  aerosolized  bron- 
choconstrictive  substances.  In:  Spector  SL.  ed.  Provocative  chal- 
lenge procedures.  Boca  Raton  FL:  CRC  Press;  1983:148. 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1457 


Improvement  in  Pulmonary  and  Exercise  Performance  in  Obese 

Patients  after  Weight  Loss 

Michael  J  Carella  MD,  Susan  Blonshine  RRT  RPFT,  C  Mohan  Gera  MD, 
Ved  V  Gossain  MD,  and  Brad  Ropp  MD 


OBJECTIVES:  (1)  To  describe  the  pulmonary  flndings  in  severely  obese  individuals  and  (2)  to 
describe  the  changes  in  resting  pulmonary  function  and  exercise  performance  after  clinically  sig- 
nificant weight  loss.  METHODS:  We  performed  flow-loop  spirometry,  lung  volumes,  diffusing 
capacity  for  carbon  monoxide  (DL^^o)'  ^"d  cycle  ergometry  with  expired  and  blood  gas  analysis  in 
16  (14  women,  2  men)  very  obese  (body-mass  index  >  40  kg/m^)  subjects  before  and  immediately 
after  6  months  of  treatment  including  a  very-low-calorie  diet.  Patients  with  a  smoking  history, 
hypoventilation  and/or  sleep  apnea  syndromes,  or  other  cardiac  or  lung  disease  were  carefully 
excluded.  RESULTS:  Patients  lost  23  ±  9.0  kg.  There  were  signiflcant  increases  in  thoracic  gas 
volume  (2.3  ±  0.54  L  versus  2.7  ±  1.1  L,  p  <  0.025)  and  expiratory  reserve  volume  (0.89  ±  0.21  L 
versus  1.46  ±  0.72  L,  p  <  0.01),  a  decrease  in  the  inspiratory  capacity  (2.8  ±  0.56  L  versus  2.5  ± 
0.49  L,  p  <  0.01),  and  a  change  in  the  relationship  between  thoracic  gas  volume  and  total  lung 
capacity.  There  were  no  significant  changes  in  other  lung  volumes,  expiratory  flow  rates  (peak  flow 
or  forced  expiratory  flow  rate  during  the  middle  50%  of  the  forced  vital  capacity),  airway  resis- 
tance, or  Dlco'  Resting  oxygen  consumption  did  not  change,  but  at  peak  exercise  the  oxygen 
consumption  per  kilogram  weight  increased,  as  did  the  ventilatory  equivalent  for  the  level  of  oxygen 
consumption.  CONCLUSIONS:  Our  results  among  carefully-selected  patients  accurately  reflect  the 
pulmonary  function  changes  in  uncomplicated  ("healthy"),  severely  obese  women.  When  changes  in 
other  lung  volumes,  airway  resistance,  DL<jo»  or  blood  gas  tensions  are  found,  evaluation  for  other 
causes  of  pulmonary  disease  should  be  undertaken.  Weight  loss  leads  to  clinically  important  in- 
crease in  lung  volume  and  modest  improvement  in  maximum  aerobic  capacity,  even  when  normal 
weight  is  not  attained.  [Respir  Care  1 999;44(  1 2):  1 458  -1 464]  Key  words:  pulmonary  function,  obesity, 
weight  loss,  very  low  calorie  diet. 


Background 

It  is  estimated  that  over  34  million  adult  Americans  are 
overweight  and  that  the  prevalence  of  obesity  is  increasing 
in  the  general  population.'  Obesity  is  often  associated  with 
cardiovascular,  pulmonary,  metabolic,  and  other  abnor- 


Michael  J  Carella  MD,  Ved  V  Gossain  MD,  and  Brad  Ropp  MD  are 
affiliated  with  the  Department  of  Medicine,  Michigan  State  University, 
East  Lansing.  Michigan.  Michael  J  Carella  MD  and  Ved  V  Gossain  MD 
are  affiliated  with  the  Weight  Management  Center.  Sparrow  Hospital, 
Lansing.  Michigan.  Susan  Blonshine  RRT  RPFT  and  C  Mohan  Gera 
MD  are  affiliated  with  the  Michigan  Capital  Medical  Center,  Lansing, 
Michigan. 

Correspondence:  Michael  J  Carella  MD.  Michigan  State  University. 
B220-A  Life  .Sciences  Building,  East  Lansing  Ml  48824-1317.  E-mail: 
mjcarella@aol.com. 


malities  that  are  believed  to  lead  to  excess  morbidity  and 
mortality  among  such  patients. - 

The  most  severe  cardiopulmonary  complications  among 
obese  patients  include  sleep  apnea  syndrome  (SAS),  obe- 
sity hypoventilation  syndrome  (OHS),  pulmonary  hyper- 
tension, and  heart  failure,  which  can  occur  alone  or  in 
combination."'  However,  asymptomatic  obese  individuals 
also  have  been  shown  to  exhibit  characteristic  pulmonary 
function  abnormalities.  Most  studies  have  found  that  func- 
tional residual  capacity  (FRC)  and  expiratory  reserve  vol- 
ume (ERV)  are  decreased.  Previous  studies  had  various 
results  with  respect  to  other  lung  volumes  such  as  diffus- 
ing capacity  for  carbon  monoxide  (Dlco)  ^^^  blood  gas 
tensions. ^-'^  In  addition,  the  effects  of  obesity  on  airway 
caliber  and  resistance  remain  controversial. '"''^ 

Numerous  studies  have  found  that  weight  loss  improves 
resting  pulmonary  function  and  exercise  capacity;  how- 
ever, the  measures  reported  have  been  either  inconsistent 


1458 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Pulmonary  Function  and  Weight  Loss 


or  not  tested  among  different  studies.^  '  ii- 17  21  -j^j^j^  j^  jyg 
in  part  to  methodological  differences  and  inclusion  of  smok- 
ers and  patients  with  SAS/OHS  or  other  pulmonary  or 
cardiac  disease  in  the  studies. 

We  performed  complete  static  pulmonary  function  and 
exercise  testing  with  blood  and  expired  gas  analysis  mea- 
surements in  obese  but  otherwise  healthy  individuals  be- 
fore and  immediately  after  6  months  of  treatment  with  a 
very  low  calorie  diet  (VLCD).  It  would  be  expected  that 
the  very  obese  but  otherwise  uncomplicated  patient  would 
show  a  dramatic  response  to  weight-loss  treatment  and 
probably  reflect  the  spectrum  of  changes  that  occur  with 
significant  weight  gain  or  loss.  We  analyzed  and  herein 
report  actual  values  for  the  pulmonary  function  testing, 
instead  of  simply  percent-of-predicted  values  that  might 
not  accurately  reflect  an  obese  population.  Unlike  case- 
control  studies,  our  patients  served  as  their  own  controls, 
allowing  for  more  direct  comparisons  between  different 
patient  weights. 

The  purposes  of  the  study  were  ( 1 )  to  describe  the  pul- 
monary findings  in  severely  obese  individuals,  and  (2)  to 
describe  the  changes  in  resting  pulmonary  function  and 
exercise  performance  with  clinically  significant  weight  loss 
using  a  VLCD. 


Methods 


Selection  of  Subjects 


The  study  was  approved  by  the  Institutional  Research 
and  Review  Committees  at  Michigan  State  University, 
Sparrow  Hospital,  and  Michigan  Capital  Medical  Center. 
Sixteen  patients  (14  women,  2  men)  who  had  been  referred 
to  the  Weight  Management  Center  of  Sparrow  Hospital 
were  invited  to  participate,  and  informed  consent  was  ob- 
tained from  each  patient.  The  patients  fulfilled  the  follow- 
ing criteria:  extreme  obesity  (body  mass  index  [BMI]  > 
40  kg/m^);  no  history  of  cigarette  smoking;  no  clinical  or 
laboratory  evidence  of  endocrine  disorders;  and  no  cardio- 
respiratory abnormalities,  including  SAS,  OHS,  or  pulmo- 
nary hypertension.  The  latter  was  ascertained  on  the  basis 
of  clinical  history  (observed  apnea,  agitated  sleep,  snoring, 
daytime  somnolence,  early  morning  headaches),  physical 
examination,  1 2-lead  electrocardiogram,  posterior-anterior 
chest  radiograph,  lateral  chest  radiograph,  baseline  mea- 
surement of  arterial  blood  gases  (ABGs),  and  pulmonary 
function.  All  testing  was  normal.  None  of  the  patients 
showed  evidence  of  hypoxemia,  hypercapnia,  abnormal 
Dlco'  oi"  increased  pulmonary  vasculature  on  chest  radio- 
graph. Three  patients  reported  symptoms  suggestive  of 
sleep-disordered  breathing,  but  formal  sleep  studies  were 
normal.  A  chemistry  profile,  urinalysis,  complete  blood 
count,  and  thyroid  function  (either  a  T4  and  T,  resin  up- 


take or  a  sensitive  thyroid-stimulating  hormone  level)  were 
normal. 

Weight-Loss  Protocol 

For  1 2  weeks,  patients  consumed  an  800-calorie  (3.4  kJ) 
Optifast*  liquid  supplement  that  provides  70  g  of  protein, 
and  no  additional  foods.  The  diet  was  followed  by  gradual 
replacement  of  the  liquid  supplement  (Weeks  14-18).  and 
stabilization  thereafter  on  a  conventional  meal  plan  of 
1000-1200  calories  (4.2-5.0  kJ)  until  Week  26.  Patients 
were  told  not  to  increase  their  physical  activity  for  the  first 
6  weeks  of  treatment.  After  this  period,  they  were  encour- 
aged to  gradually  increase  their  exercise,  which  usually 
consisted  of  walking. 

Anthropometric  and  Body  Composition  Methods 

Height  was  measured  to  the  nearest  centimeter,  using  a 
Holtian  stadiometer.  Weight  was  measured  to  the  nearest 
0. 1  kg  in  stocking  feet  on  a  standard  calibrated  weighing 
balance.  BMI  was  calculated  from  height  and  weight  mea- 
sures (kg/m^).  Waist  circumference  was  measured  at  the 
level  of  the  umbilicus  and  the  hip  girth  at  the  greater 
trochanter. 

After  8  hours  of  fasting  and  with  the  bladder  empty, 
body  composition  was  measured  with  a  bioelectrical  im- 
pedance analyzer,  as  described  by  Lukaski,^^  using  pro- 
prietary equations  supplied  by  the  manufacturer. 

Pulmonary  Function  Studies 

In  all  subjects,  flow-volume  spirometry  (conducted  with 
a  1085  System  spirometer)  was  performed  according  to 
American  Thoracic  Society  performance,  acceptability,  and 
reproducibility  standards  and  American  Association  for 
Respiratory  Care  Clinical  Practice  Guidelines.-^  FRC  (mea- 
sured directly  as  thoracic  gas  volume  [TGV])  and  airway 
resistance  were  determined  in  a  variable-pressure,  con- 
stant-volume body  plethysmograph  (1085  System)  accord- 
ing to  American  Thoracic  Society  and  American  Associ- 
ation for  Respiratory  Care  performance  criteria.-" 
Inspiratory  capacity  (IC)  and  slow  vital  capacity  were  mea- 
sured via  plethysmography  in  conjunction  with  TGV.  To- 
tal lung  capacity  (TLC),  residual  volume  (RV),  ERV,  and 
specific  airway  conductance  were  calculated  from  these 
direct  measurements.  D[  f-Q  and  alveolar  gas  volume  (V^) 
at  TLC  were  measured  with  a  1070  System,  using  the 
single-breath  technique,  with  neon  as  the  inert  gas,  accord- 


Suppliers  of  commercial  products  are  identified  in  the  Product  Sources 
section  at  the  end  of  the  text. 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1459 


Pulmonary  Function  and  Weight  Loss 


ing  to  American  Thoracic  Society  and  American  Associ- 
ation for  Respiratory  Care  performance  criteria.--'' 

Maximum  oxygen  consumption  (Vq  )  with  continuous 
pulse  oximetry  (measured  with  a  3700  System  pulse  oxime- 
ter) was  performed  using  cycle  ergometry.  An  exercise 
ramp  protocol  preceded  by  a  2-minute  warm-up  was  com- 
pleted using  20  watts/minute  increments.-''  The  end  point 
of  exercise  was  patient  fatigue  and  a  plateau  in  Vq,-  An 
arterial  catheter  was  placed  in  the  brachial  artery,  and 
blood  samples  for  blood  gas  analysis  were  drawn  in  the 
sitting  position  at  rest  and  at  peak  exercise.  Arterial  oxy- 
gen tension,  arterial  carbon  dioxide  tension,  arterial  blood 
pH,  oxygen  saturation  of  the  hemoglobin  of  arterial  blood, 
and  base  excess  were  analyzed  with  a  BG3/482  Co- 
Oximeter  automated  acid-base  analyzer.  Computerized 
continuous  gas  analysis  was  measured  using  a  CPX-MAX 
breath-by-breath  system.  Vq  ,  carbon  dioxide  production 
(Vpo,),  and  minute  ventilation  (Vg)  were  recorded  at  rest, 
at  the  anaerobic  threshold,  and  at  maximum  or  peak  per- 
formance. Maximum  voluntary  ventilation  was  measured 
at  peak  exercise.  Heart  and  rhythm  were  monitored  con- 
tinuously with  a  1 2-lead  electrocardiogram,  and  blood  pres- 
sure was  measured  manually  with  a  hand-held  sphygmo- 
manometer. With  all  subjects,  testing  was  completed  in  the 
morning.  The  exercise  test  was  performed  after  resting 
pulmonary  function  measurements  were  completed. 

Statistical  Analyses 

Data  are  expressed  as  mean  ±  standard  deviation.  The 
paired  Student's  t  test  was  used  to  compare  the  measures 
before  and  after  weight  loss.  Because  of  the  number  of 
variables  in  the  analysis,  only  those  measures  that  achieved 
a  p  <  0.025  were  considered  statistically  significant  (Bon- 
feroni  method),  in  order  to  minimize  the  potential  for  a 
error.  Univariate  Pearson  correlation  and  multiple  variable 


Table  2.      Spirometry  Before  and  After  Weight  Loss* 


Baseline 

After  Treatment 

FVC  (L) 

3.6  ±  0.68 

4.0  ±  0.90t 

FEV,  (L) 

3.1  ±0.58 

3.3  ±  0.68t 

FEV,/FVC 

84  ±3 

83  ±4 

FEF,,_,,  (L/s) 

3.6  ±  0.91 

3.7  ±  1.0 

FEF„„,  (L/s) 

9.1  ±  2.0 

9.3  ±  1.9 

MVV  (L/min) 

118  ±  17 

129  ±  30 

*E\pressed  as  mean  ±  standard  deviation,  n  -  16. 

tp  <  0.001  versus  prior  to  treatment. 

FVC  =  forced  vital  capacity. 

FEV]  =  forced  expiratory  volume  in  the  first  second. 

FEV|/FVC  =  ratio  of  FEV,  to  FVC. 

f  EF25.75  =  forced  expiratory  flow  rate  during  the  middle  50%  of  the  FVC. 

FEFmy^  -  peak  flow. 

MVV  -  maximal  voluntary  ventilation. 


contribution  of  weight  and  other  variables  to  any  differ- 
ence in  these  measures.  The  distribution  of  the  data  was 
assessed  and  nonparametric  tests  were  used  when  appro- 
priate. All  statistical  analyses  were  performed  with  SPSS 
release  6.0. 

Results 

Table  1  summarizes  the  anthropometric  data  before  and 
after  weight  loss.  After  6  months  of  treatment,  the  patients 
lost  a  mean  of  23  ±  9.0  kg  (23%  of  body  weight).  There 
were  statistically  significant  changes  in  both  lean  body 


Table  3.      Lung  Volumes,  Airway  Mechanics,  and  Diffusing  Capacity 
Before  and  After  Weight  Loss* 


Baseline 


After 
Treatment 


hnear  regression  anal) 

'ses  were  pei 

formed  to  an 

ilyze  vari- 

TLC  (L) 

5.0  ±  0.94 

5.1  ±  1.4 

ance  in  the  pulmonary 

function  measures  and  the  potential 

IC(L) 
TGV  (L) 

2.8  ±  0.56 
2.3  ±  0.54 

2.5  ±  0.49t 
2.7  ±  Lit 

RV(L) 

1.4  ±0.44 

1.2  ±0.61 

Table  1.      Change  in  Weight  and  Body  Composition  with  Treatment* 

ERV  (L) 

R,,^  (cm  H,0/L/s) 

sG,^  (s/cm  HjO  X  L-) 

Dlco  (mL/min/mm  Hg) 

DlcoA'a 

0.89  ±0.21 

1.5  ±0.36 
0.24  ±  0.05 

27  ±  7.2 

5.5  ±  0.58 

n  =  16. 

oxide. 

carhon  monoxide  lo  alveolar 

1.46±0.72t 

1.4  ±0.43 
0.24  ±  0.07 

28  ±  6.6 

5.3  ±  0.88 

i 

volume. 

Baseline 

After 
Treatment 

Percent 
Change 

Age  (years) 

46  ±  9.8 

0,849  ±0.105 

127  ±  24 

0.76  ±  0. 1 3 

46  ±  7.4 

63  ±  15 

64  ±  18 

iation.  n  =  16. 

0.857  ±  0.090 
97  ±  25t 
0..59±0.15t 
.35  ±  8.7t 
57  ±  lot 
40  ±  22t 

-23  ±  9.0 
-23  ±  9.0 
-23  ±  9.0 
-9    ±  8.7 
-38  ±  17 

Waist:  Hip 
Weight  (kg) 
Weight/height  (kg/cm) 
Body  mass  index  (kg/m") 
Fat-free  mass  (kg) 
Fat  mass  (kg) 

♦Expressed  as  mean  ±  standard  deviation. 

tp  <  0.01  versus  prior  lo  treatment. 

tp  <  0.025. 

TLC  =  total  lung  capacity. 

IC  -  inspiratory  capacity. 

TGV  -  thoracic  gas  volume. 

RV  =  residual  volume. 

ERV  -  expiratory  reserve  volume. 

Raw  ~  airway  resistance. 

sGav,,  =  specific  airway  conductance. 

Dlco  =  diffusing  capacity  for  carbon  mon 

Djf  o/V^  -  ratio  of  diffusing  capacity  for 

•Expressed  as  mean  ±  standard  dcv 
+p  <  0.001  versus  prior  to  treatmcn 
tp  <  0.005. 

1460 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Pulmonary  Function  and  Weight  Loss 


Table  4a.      Change  in  Cardiopulmonary  Measures  at  Peak  Exercise  with  Treatment* 


Baseline 

After  Treatment 

%  Change 

Work  (watts) 

121  ±43 

130  ±52 

+7±  19 

VO2  (mL/min) 

2,283  ±  724 

1.975  ±6l8t 

-12±  16 

VOj/kg  (mL/min-kg) 

17.9  ±  4.5 

21.1  ±7.61: 

+  16±  24 

Vo,/work  (mL/min- watts) 

20.4  ±  4.3 

17.7  ±  5.0§ 

-13±  15 

Ve  (L/min) 

85  ±  22.2 

84  ±  28.5 

-2±  19 

VeA'o,  (L/mL) 

38  ±  45.5  X  10   ' 

43  ±  70.6  X  lO't 

+  13±  15 

VOj/heart  rate  (mL/beat) 

14  ±  4.9 

13  ±  3.6 

-8  ±  16 

Work/heart  rate  (watts-minfteats) 

0.03  ±  0.01 

0.04  ±0.0 It 

+  20  ±  22 

Systolic  blood  pressure  (mm  Hg) 

183  ±  25.0 

exercise,  n  =  14. 

164±21.8t 

-10±  10 

♦Expressed  as  mean  ±  standard  deviation  at  peaic 

tp  <  0.01. 

tp  <  0.025. 

§p  <  0.001. 

V02  =  oxygen  consumption. 

Voi/kg  =  oxygen  consumption  per  kilogram  weight. 

V02/work  =  oxygen  consumption  per  watt  work. 

Ve  =  minute  ventilation. 

V02/ heart  rate  ^  O2  putse. 

Ve'^Ot  ^  respiratory  quotient. 

Table  4b.      Change  in  Arterial  Blood  Gas  Measures  at  Peak  Exercise 

7 

4.5  J 

with  Treatment* 

6 

y* 

4 
3.5 

3 
2.5 

"\ 

Baseline 

After  Treatment       %  Change 

3 

5 
4 

J 

/      ^^      ^^ 

5 

/        ^ 

P,o,  (mm  Hg)                      98  ±  9.4 

107  ±7.9           +10  ±11 

3  ' 

if. 

-*   ^^3   ^^3 

1 

2 

/^        ^^5 

Paco,  (mm  Hg)                  34  ±  3.6 

31  ±  3.6           -10±  13 

_s 

■A      ^^^^ 

3 

1  5 

X/^     ^^*^ 

P,A-a)o,  (mm  Hg)                17  ±6.8 

12  ±5.7            -6  ±100 

> 

2^^ 

% 

> 

1 

^^ 

VdA't(%)                         15  ±7 

14  ±  6               -2  ±  0.98 

1  "■ 

0.5 

^ Jl    J^ 

^ 

pH                                   7.34  ±  0.05 

7.35  ±  0.06        +0.1  ±0.44 
-5.97  ±  4.07           +4  ±  63 

0 

0 

^~^ 

Base  excess                  -6.33  ±  2.66 

TGV 

FEV.                  FVC 

ERV               IC 

2.3  (.54) -2.7  (1.10)     3.1  (J8)  -  3.3  (.68)      3.6  (.68)  -  4.0  (.90 

«(JI)-I.«(.72)    2J(.5«)-2.5(.«) 

^Expressed  as  mean  ±  standard  deviation  at  peak  exercise,  n  =  1. 

P.iOi  "  arterial  oxygen  tension. 

PaCOi  ~  arterial  carbon  dioxide  tension. 

P(A-a)02  ~  alveolar-arterial  oxygen  tension  difference, 

\nNi  =  dead  space  volume/tidal  volume. 


mass  (p  <  0.005)  and  fat  mass  (p  <  0.00 1 ).  but  80%  of  the 
weight  loss  consisted  of  adipose  tissue. 

Tables  2,  3,  and  4  summarize  the  results  of  resting  pul- 
monary function  and  exercise  testing.  Figure  1  shows  in- 
dividual data  for  the  subjects.  When  the  two  male  subjects 
were  excluded  from  the  analyses,  the  results  were  similar. 
Therefore,  mean  data  for  all  16  subjects  are  reported  when 
available.  All  16  patients  had  complete  anthropometric, 
spirometry,  lung  volume,  and  Dj^q  data  available  (see 
Tables  1-3).  Two  women  had  incomplete  exerci.se  data, 
and  an  additional  7  patients  (5  women,  2  men)  had  incom- 
plete ABG  measurements  because  of  technical  difficulties. 
Therefore,  only  14  patients  were  used  in  the  exercise  anal- 
ysis (see  Table  4a)  and  7  patients  in  the  ABGs  analysis 
(.see  Table  4b).  Pulmonary  function  data  are  reported  as 
the  measured  value  (not  percent-of-predicted  from  refer- 
ence population)  in  all  subjects.  Note  that  most  pulmonary 


Fig.  1.  InidivicJual  subject  responses  in  pulmonary  measures  that 
changed  significantly  with  weight  loss.  In  each  part  of  the  graph, 
the  left-hancJ  (dots  indicate  the  measurements  before  weight  loss 
and  the  right-hand  dots  indicate  the  measurements  after  weight 
loss.  The  numbers  represent  the  means  ±  standard  deviation. 
TGV  =  thoracic  gas  volume.  FEV,  =  forced  expiratory  volume  in 
the  first  second.  FVC  =  forced  vital  capacity.  ERV  =  expiratory 
reserve  volume.  10  =  inspiratory  capacity. 


function  measurements  were  within  the  normal  predicted 
values  for  every  subject,  even  before  treatment.  The  only 
exceptions  were  the  RV,  ERV,  and  IC,  which,  in  some 
cases,  before  treatment,  were  outside  the  predicted  refer- 
ence range  for  height  and  weight.-''  The  mean  percent-of- 
predicted  values  for  RV  and  IC  before  treatment  were 
74  ±  16.1%  and  84  ±  14.8%  of  predicted  for  the  popu- 
lation, respectively. 

Table  2  shows  the  results  of  spirometry  before  and  after 
weight  loss.  Forced  vital  capacity  (FVC)  and  forced  expi- 
ratory volume  in  the  first  second  (FEV,)  were  higher  after 
weight  loss,  but  the  FEV|/FVC  ratio  did  not  change.  Max- 
imum voluntary  ventilation  was  greater  after  weight  loss, 
but  this  change  was  not  statistically  significant  (p  =  0.07). 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1461 


Pulmonary  Function  and  Weight  Loss 


The  change  in  maximum  voluntary  ventilation  correlated 
with  the  change  in  TGV  (r  =  0.85,  p  <  0.01). 

Table  3  summarizes  the  results  of  lung  volume  changes, 
airway  mechanics,  and  diffusing  capacity  before  and  after 
weight  loss.  After  weight  loss  TGV  and  ERV  were  sig- 
nificantly higher,  whereas  IC  was  significantly  lower.  There 
were  no  significant  changes  in  RV,  TLC,  airway  flow  rates 
(forced  expiratory  flow  rate  during  the  middle  50%  of 
FVC,  maximum  forced  expiratory  flow),  airway  resistance, 
specific  airway  conductance,  or  Dl^o  normalized  to  alve- 
olar volume. 

Correlation  analysis  between  the  change  in  weight  and 
the  changes  in  spirometry  results  and  lung  volume  (see 
Tables  2  and  3)  shows  that  weight  was  a  significant  de- 
terminant for  all  the  measures  that  changed.  TGV  showed 
the  greatest  proportional  change  with  weight  loss,  nearly  a 
30%  increase.  Multiple  variable  regression  analysis  indi- 
cated that  the  decrease  in  body  surface  area  and  weight/ 
height  ratio  best  predicted  the  increase  in  TGV  (r~  =  0.83, 
p  <  0.0001).  The  regression  equation  for  the  change  in 
TGV  is  as  follows: 

8.77  X  10"  (change  in  weight:height  ratio  in  kgxm)  - 
7.71  X  10'  (change  in  body  surface  area  in  m")  -I-  20.17. 

After  weight  loss  there  were  statistically  significant  de- 
creases in  resting-state  heart  rate  (85  ±  13  beats/min  be- 
fore weight  loss  versus  72  ±  15  beats/min  after  weight 
loss,  p  <  0.00 1 ),  resting-state  diastolic  blood  pressure  (8 1  ± 
13  mm  Hg  versus  73  ±  8  mm  Hg,  p  <  0.025),  heart  rate 
during  exercise  testing  at  anaerobic  threshold  (115  ±  17 
beats/min  versus  107  ±  14  beats/min,  p  <  0.025),  and 
blood  pressure  during  exercise  testing  at  anaerobic  thresh- 
old (83  ±  8  mm  Hg  versus  76  ±  7  mm  Hg,  p  <  0.01). 

Oxygen  consumption  at  rest  (uncorrected  or  corrected 
for  lean  body  mass  weight)  was  not  different  after  weight 
loss.  Other  cardiopulmonary  measures  (Vg,  V^o,.  V^/Vq  , 
and  Vp/V(;o,)  '^^  ""est  or  at  anaerobic  threshold  were  also 
not  different  after  weight  loss  (data  not  shown).  In  con- 
trast, some  variables  showed  statistically  significant  dif- 
ferences at  peak  exercise  after  weight  loss  (see  Tables  4a 
and  4b).  After  weight  loss,  systolic  blood  pressure  was 
significantly  lower  during  peak  exercise  (p  <  0.01)  and 
oxygen  consumption  per  kilogram  of  weight  (Vo/kg)  at 
peak  exercise  was  significantly  higher  (p  <  0.025),  in- 
creasing by  nearly  25%.  After  weight  loss,  oxygen  con- 
sumption for  the  amount  of  work  performed  was  lower, 
and  the  ventilatory  equivalent  for  the  level  of  oxygen  con- 
sumption (Vf;/V„  )  was  significantly  higher  at  peak  exer- 
cise (p  <  0.001).  ABG  tensions  for  oxygen  and  carbon 
dioxide  and  the  alveolar-arterial  oxygen  tension  difference 
were  not  different  after  weight  loss,  at  rest  or  at  peak 
exercise.  However,  ABG  data  were  available  in  only  7 
subjects  (because  of  technical  difficulties),  and  these  mea- 
sures showed  a  tendency  to  improve  after  weight  loss. 


Discussion 

Our  results  suggest  that  weight  loss  primarily  affects 
lung  volumes  in  severely  obese  individuals.  Indeed,  the 
TGV  (FRC)  and  ERV  show  the  greatest  proportional  change 
with  weight  loss  and  represent  the  most  sensitive  indicator 
for  the  effects  of  obesity  on  resting  pulmonary  function. 
Our  patients  also  had  greater  IC  before  weight  loss.  In 
addition,  our  results  show  that  clinically  significant  weight 
loss  decreases  the  metabolic  requirements  for  exercise  (ie, 
increased  Ve/Vq  ,  and  decreased  Vq /work)  and  modestly 
increases  maximum  aerobic  capacity  (Vo,/kg).  In  other 
words,  after  significant  weight  loss  our  patients  expended 
less  energy  at  similar  or  greater  work  loads  and  their  breath- 
ing was  "less  labored."  We  feel  the  results  in  our  carefully 
selected  patients  accurately  reflect  the  changes  in  lung 
volumes  that  occur  in  uncomplicated  or  healthy  obese 
women. 

Our  patients  were  very  obese  before  treatment  (BMI 
46  ±  7.4  kg/m^).  However,  they  remained  substantially 
obese  on  average  (BMI  35  ±  8.5  kg/m~),  even  after  con- 
siderable weight  loss.  Therefore,  it  is  possible  that  some 
variables  that  did  not  change  in  our  study  might  change  if 
normal  weight  were  achieved.  This  may  be  true  for  RV, 
which,  along  with  ERV  and  IC,  was  the  only  other  vari- 
able to  be  outside  the  normal  predicted  values  in  some 
subjects. 

Because  of  the  change  in  TGV,  one  might  expect  an 
improvement  in  blood  gas  tensions  and  in  ventilation-per- 
fusion  matching.  In  fact,  the  arterial  oxygen  tension,  arte- 
rial carbon  dioxide  tension,  and  alveolar-arterial  oxygen 
tension  difference  showed  a  tendency  to  improve  at  peak 
exercise  but  did  not  reach  statistical  significance,  probably 
because  of  the  small  number  of  patients  for  whom  these 
data  were  available.  Moreover,  an  expected  change  in  the 
arterial  carbon  dioxide  tension  would  be  consistent  with 
the  observed  statistically  significant  increase  in  the  Ve/Vq^ 
in  our  study.  Therefore,  the  limited  number  of  patients 
included  in  the  ABG  analysis  is  a  major  limitation  of  our 
study,  and  a  larger  number  of  patients  would  have  strength- 
ened our  results. 

One  might  argue  that  the  increase  in  Vg/Vo,  was  be- 
cause of  the  lack  of  adaptation  of  neural  regulation  of 
breathing  with  rapid  weight  loss.  However,  we  believe  this 
is  unlikely,  because  most  of  the  rapid  weight  loss  occurred 
during  the  first  13  weeks  on  the  liquid-protein  supplement, 
and  the  repeat  testing  was  done  after  another  1 3  weeks  had 
passed,  during  which  less  dramatic  weight  loss  occurred 
on  conventional  food  (see  Methods,  Weight-Loss  Proto- 
col). For  the  same  reason,  we  feel  that  the  hyperventilation 
observed  only  during  peak  exercise  was  not  due  to  the 
metabolic  acidosis  of  rapid  weight  loss;  rather,  hyperven- 
tilation was  likely  induced  by  the  accumulation  of  potas- 
sium and  hydrogen  ions  during  heavy  exercise.  The  in- 


1462 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Pulmonary  Function  and  Weight  Loss 


crease  in  Ve/Vq  results  from  the  decrease  in  Vq^  or  a 
decreased  metabolic  requirement  for  exercise  after  weight 
loss. 

We  did  not  measure  or  control  physical  activity  during 
weight-loss  treatment.  Therefore,  it  is  possible  that  exer- 
cise could  partially  explain  the  improvement  in  some  car- 
diopulmonary measures  during  dynamic  testing.  However, 
the  role  of  exercise  was  probably  minimal  because  it  was 
not  an  essential  part  of  the  weight-loss  intervention.  The 
limited  effect  of  exercise  is  also  supported  by  the  finding 
that  our  patients  on  average  lost  some  fat-free  mass  during 
treatment  (see  Table  1). 

Obesity  may  adversely  affect  pulmonary  function  via 
several  mechanisms.  In  our  study,  the  decrease  in  body 
surface  area  mostly  explained  the  increase  in  TGV  (r^  = 
0.67).  Increased  body  surface  and  mass  load  on  the  chest 
wall  cause  lung-volume  changes.  The  change  in  the  rela- 
tionship between  TGV  (FRC)  and  TLC  is  probably  due  to 
a  change  in  the  static  position  of  the  chest  wall  and  dia- 
phragm."'-*' The  chest  wall  and  diaphragm  at  end-expira- 
tion are  less  deformable  and  thus  encroach  on  TGV  (FRC) 
and  ERV  of  the  lungs.  Ventilatory  work  is  increased  be- 
cause of  changes  in  chest-wall  compliance  and  also  pos- 
sibly because  of  respiratory  muscle  inefficiency,'"-''  lead- 
ing to  higher  than  normal  oxygen  consumption  and  carbon 
dioxide  production  rates. ^^  Similar  lung-volume  abnormal- 
ities are  seen  in  nonobese  individuals  who  undergo  exper- 
imental chest  strapping  and/or  are  given  abdominal  weight 
to  carry. ^'  Our  study  found  that  these  changes  are  revers- 
ible with  significant  weight  loss.  Moreover,  even  though 
our  patients  remained  considerably  obese  after  treatment 
(BMI  35  ±  8.7  kg/m^),  loss  of  >  20%  excess  body  weight 
led  to  clinically  significant  increase  in  lung  volume  and 
improvement  in  Vq /kg. 

The  most  severe  cardiopulmonary  complications  among 
obese  patients  are  SAS,  OHS,  pulmonary  hypertension, 
and  heart  failure. "*  In  addition,  when  lung  volumes  become 
severely  diminished,  small  airway  closure  (atelectasis)  and 
ventilation-perfusion  ratio  mismatch  may  occur  in  the  de- 
pendent lung  zones. '""'2  jj^is  is  further  supported  by  ob- 
servations of  Ray  et  al,  who  found  that  changes  in  FRC 
and  ERV  were  correlated  with  the  degree  of  weight  gain, 
whereas  abnormalities  of  other  lung  volumes  and  gas  ex- 
change tend  to  occur  in  super-morbidly-obese  patients." 
Also,  some  obese  individuals  may  be  vulnerable  to  these 
changes  when  supine,  under  anesthesia,  or  when  confronted 
by  some  other  respiratory  embarrassment.^-  In  our  study, 
we  also  observed  a  trend  toward  greater  inefficiency  of  gas 
exchange  (alveolar-arterial  oxygen  tension  difference)  at 
peak  exercise,  which  showed  a  tendency  to  improve  with 
weight  loss  but  did  not  reach  statistical  significance. 

Our  results  agree  with  previous  weight-loss  stud- 
igs6,i  1.12.17-21  (fja(  found  consistent  improvement  in  FRC 
and  ERV  and  no  evidence  of  airway  obstruction  (ie,  nor- 


mal FEV,/FVC  and  normal  airway  resistance).  All  other 
pulmonary  measures  (for  example,  other  lung  volumes, 
Dlco'  ^nd  ABG  analysis)  were  either  inconsistently  re- 
ported or  not  performed  in  most  other  studies.  The  dis- 
crepancies in  previous  weight-loss  studies  in  other  lung 
volume  measurements,"*"-'  Dico-**  ^nd  blood  gas  anal- 
ysis'2'9  are  due,  in  part,  to  methodological  differences  and 
improper  patient  selection.  Most  of  the  studies  either  in- 
cluded cigarette  smokers,  patients  with  OHS/SAS  or  other 
pulmonary  disease,  or  did  not  report  the  participants'  smok- 
ing histories.  Also,  these  studies  compared  percent-of-pre- 
dicted  values,  which  may  not  be  appropriate  for  an  obese 
population.  Nevertheless,  our  results  agree  with  all  weight 
loss  studies^-^^-^-'^''--^  that  showed  no  change  in  airway 
caliber  or  resistance  with  weight  loss.  Our  results  conflict 
with  those  of  the  case  control  study  of  Rubinstein  et  al," 
who  found  air  flow  limitation  in  morbidly  obese,  non- 
smoking men.  This  discrepancy  may  be  because  our  study 
patients  (like  most  other  studies)  are  primarily  women. 
Gender  difference  may  be  important:  there  are  preliminary 
data  to  suggest  that  upper  body  obesity  and  visceral  adi- 
posity may  have  a  greater  effect  on  pulmonary  function.^'' 
However,  we  believe  that  abnormalities  of  airway  resis- 
tance should  prompt  evaluation  for  other  causes  of  pul- 
monary disease.  Further  studies  in  obese  men,  including 
weight-loss  studies,  are  needed  to  better  clarify  this  issue. 

Conclusions 

Our  findings  suggest  that  severe  obesity  is  associated  with 
significant  pulmonary  function  changes,  primarily  de- 
creased lung  volumes  and  decreased  metabolic  require- 
ments for  exercise.  The  uncomplicated  primarily  obese 
women  in  this  study  showed  no  evidence  of  increased 
airway  resistance  or  abnormal  Dlco-  Clinically  significant 
weight  loss  led  to  an  increase  in  TGV  (FRC)  and  FVC,  a 
decrease  in  IC,  and  a  modest  improvement  in  Vo,/kg.  Fur- 
ther studies  are  needed  of  severely  obese  men  to  determine 
whether  there  is  a  significant  gender  difference  in  the  pul- 
monary response  to  weight  loss. 

ACKNOWLEDGMENTS 

The  authors  wish  to  thank  the  staff  of  the  pulmonary  laboratory  at  Mich- 
igan Capital  Medical  Center  (Greenlawn  campus)  for  their  technical 
assistance. 

PRODUCT  SOURCES 

Liquid  Diet  Supplement 

Optifast,  Novartis,  Basel,  Switzerland 
Bioelectrical  Impedance  Analyzer 

RJL  Systems,  Detroit  MI 
Flow- Volume  Spirometer 

1085  System,  Medical  Graphics,  Minneapolis  MN 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1463 


Pulmonary  Function  and  Weight  Loss 


Plethysmograph 

1085  System,  Medical  Graphics,  Minneapolis  MN 
Dlco  3nd  Alveolar  Gas  Volume  Analyzer 

1070  System,  Medical  Graphics,  Minneapolis  MN 
Pulse  Oximeter 

3700  System,  Ohmeda  Biox,  Boulder  CO 
Acid-Base  Analyzer 

BG3/482  Co-Oximeter,  Instrumentation  Laboratory, 
Lexington  MA 
Continuous  Gas  Analyzer 

CPX-MAX,  Medical  Graphics,  Minneapolis  MN 
Statistics  Software 

SPSS  release  6.0,  Chicago  IL 


REFERENCES 


1.  Naijar  MF,  Rowland  M.  U.S.  Public  Health  Service.  Anthropometric 
reference  data  and  prevalence  of  overweight.  United  States,  1976- 
80.  National  Center  for  Health  Statistics,  Hyattsville,  MD.  Vital  and 
Health  Statistics,  1987;[Series  11,  No.  238,  DHHS  publication 
No.(PHS)87-l688.] 

2.  Methods  for  voluntary  weight  loss  and  control.  Proceedings  of  the 
NIH  Technology  Assessment  Conference.  Bethesda  MD.  Ann  Intern 
Med  1993;1I9(7  Pt  2):641-770. 

3.  Lopata  M,  Onal  E.  Mass  loading,  sleep  apnea,  and  the  pathogenesis 
of  obesity  hypoventilation.  Am  Rev  Respir  Dis  1982;126(4):640- 
64.S. 

Barrera  F,  Reidenberg  MM,  Winters  WL.  Pulmonary  function  in  the 
obese  patient.  Am  J  Med  Sci  1967;254(6):785-796. 
Bedell  GN,  Wilson  WR,  Seebohm  PM.  Pulmonary  function  in  obese 
persons.  J  Clin  Invest  1958;37:1049-1060. 

Chodoff  P,  Imbembo  AL,  Knowles  CL,  Margand  PMS.  Massive 
weight  loss  following  jejunoileal  bypass.  I.  Effects  on  pulmonary 
function.  Surgery  1977;8I(4):399^03. 

Crapo  RO,  Kelly  TM,  Elliott  CG,  Jones  SB.  Spirometry  as  a  preop- 
erative screening  test  in  morbidly  obese  patients.  Surgery  1986;99(6): 
763-768. 

8.  Cullen  JH,  Formel  PF.  The  respiratory  defects  in  extreme  obesity. 
Am  J  Med  1962;32:525-531. 

9.  Luce  JM.  Respiratory  complications  of  obesity.  Chest  1980;78(4): 
626-631. 

Naimark  A,  Cherniack  RM.  Compliance  of  the  respiratory  .system 
and  its  components  in  health  and  obesity.  J  Appl  Physiol  1960;  15: 
377-382. 

Ray  CS,  Sue  DY,  Bray  G,  Hansen  JE,  Wassermann  K.  Effects  of 
obesity  on  respiratory  function.  Am  Rev  Respir  Dis  1983;128(3): 
50 1 -.506, 

Stalnecker  MC,  Suratt  PM,  Chandler  JG.  Changes  in  respiratory 
function  following  small  bowel  bypass  for  obesity.  Surgery  1980; 
87(6):645-65 1 . 


4. 


5 


7. 


10 


11 


12, 


13.  Suratt  PM,  Wilhoit  SC,  Hsiao  HS,  Atkinson  RL,  Rochester  DF. 
Compliance  of  chest  wall  in  obese  subjects.  J  Appl  Physiol  1984; 
57(2):403-407. 

14.  Douglas  FG,  Chong  PY.  Influence  of  obesity  on  peripheral  airways 
patency.  J  Appl  Physiol  1972;33(5):559-563. 

15.  Rubinstein  I,  Zamel  N,  DuBarry  L,  Hoffstein  V.  Airflow  limitation 
in  morbidly  obese,  nonsmoking  men.  Ann  Intern  Med  1 990;  1 1 2(  1 1 ); 
828-832. 

16.  Zerah  F,  Harf  A,  Perlemuter  L,  Lorino  H,  Lorino  AM,  Atlan  G. 
Effects  of  obesity  on  respiratory  resistance.  Chest  1993;103(5):  1470- 
1476. 

1 7.  Hakala  K,  Mustajoki  P,  Aittomaki  J,  Sovijarvi  ARA.  Effect  of  weight 
loss  and  body  position  on  pulmonary  function  and  gas  exchange 
abnormalities  in  morbid  obesity.  Int  J  Obes  Relat  Metab  Disord 
l995;19(5):343-346. 

18.  Refsum  HE,  Holter  PH,  Lovig  T,  Haffner  JEW,  Stadaas  JO.  Pulmo- 
nary function  and  energy  expenditure  after  marked  weight  loss  in 
obese  women:  observation  before  and  one  year  after  gastric  banding. 
Int  J  Obes  1990;14(2):  175-183. 

19.  Thomas  PS,  Cowen  ERT,  Hulands  G,  Milledge  JS.  Respiratory  func- 
tion in  the  morbidly  obese  before  and  after  weight  loss.  Thorax 
1989;44(5):382-386. 

20.  Vaughan  RW,  Cork  RC,  Hollander  D.  The  effect  of  massive  weight 
loss  on  arterial  oxygenation  and  pulmonary  function  tests.  Anesthe- 
siology 1981;54(4):325-328. 

21.  Wadstrom  C,  MuUer-Suur  R,  Backman  L.  Influence  of  excessive 
weight  loss  on  respiratory  function:  a  study  of  obese  patients  fol- 
lowing gastroplasty.  Eur  J  Surg  1991;157(5):341-346. 

22.  Lukaski  HC,  Bolonchuk  WW.  Estimation  of  body  fluid  volumes 
using  tetrapolar  bioelectrical  impedance  measurements.  Aviat  Space 
Environ  Med  1988;59(12):1 163-1 169. 

23.  AARC  Clinical  Practice  Guideline.  Spirometry.  Respir  Care  1991; 
36(12):1414-1417. 

24.  AARC  Clinical  Practice  Guideline.  Body  plethysmography.  Respir 
Care  1994;39(12):1 184-1 190. 

25.  AARC  Clinical  Practice  Guideline.  Single-breath  carbon  monoxide 
diffusing  capacity.  Respir  Care  1993;38(5):51 1-515. 

26.  AARC  Clinical  Practice  Guideline.  Exercise  testing  for  evaluation  of 
hypoxemia  and/or  desaturation.  Respir  Care  1992;37(8):907-9I2. 

27.  Goldmann  HI,  Becklake  MR.  Respiratory  function  tests:  normal  val- 
ues at  median  altitudes  and  the  prediction  of  normal  results.  Am  Rev 
Respir  Dis  1959;79:457^67. 

28.  Hanson,  JS.  Exercise  responses  following  production  of  experimen- 
tal obesity.  J  Appl  Physiol  1973;35(5):587-591. 

29.  Davies  CT,  Godfrey  S,  Light  M,  Sargeant  AJ,  Zeidifard  E.  Cardio- 
pulmonary responses  to  exercise  in  obese  girls  and  young  women. 
J  Appl  Physiol  1975;38(3):373-376. 

30.  Caro  CG,  Butler  J,  Dubois  AB.  Some  effects  of  restriction  of  chest 
cage  expansion  on  pulmonary  function  in  man:  an  experimental  study. 
J  Clin  Invest  1960;39:573-583. 

31.  Holley  HS,  Milic-Emili  J,  Becklake  MR,  Bates  DV.  Regional  dis- 
tribution of  pulmonary  ventilation  and  perfusion  in  obesity.  J  Clin 
Invest  1967;46{4):475^81. 

32.  Hedenstierna  G,  Santesson  J.  Studies  on  intra-pulmonary  gas  distri- 
bution in  the  extremely  obese:  influence  of  anaesthesia  and  artificial 
ventilation  with  and  without  positive  end-expiratory  pressure.  Acta 
Anaesth  Scand  1977;21(4):257-265. 

33.  Collins  LC,  Hoberty  PD,  Walker  JF,  Fletcher  EC,  Peiris  AN.  The 
effect  of  body  fat  distribution  on  pulmonary  function  tests.  Chest 
I995;107(5):1298-1302. 


1464 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Performance  Comparison  of  the  Hand-Held  MicroPlus  Portable 
Spirometer  and  the  SensorMedics  Vmax22  Diagnostic  Spirometer 

LTC  William  E  Caras  MD,  Michael  G  Winter  RRT,  COL  Thomas  Dillard  MD, 

and  Tammy  Reasor  RPFT 


BACKGROUND:  Portable  spirometry  offers  many  potential  advantages  over  conventional  lung 
function  measurements  obtained  in  a  pulmonary  function  laboratory.  METHODS:  We  compared 
the  performance  characteristics  of  the  MicroPlus  portable  spirometer  with  the  SensorMedics  Vmax22 
diagnostic  spirometer  used  in  our  pulmonary  function  laboratory.  Lung  function  measurements 
(forced  expiratory  volume  [FVC],  forced  expiratory  volume  in  the  first  second  [FEV,],  and  peak 
expiratory  flow  [PEF])  were  obtained  from  both  instruments  simultaneously,  during  the  same 
forced  expiratory  maneuver.  The  study  group  consisted  of  20  normal  subjects,  20  asthmatics  with 
mildly  reduced  lung  function,  and  20  severely  obstructed  chronic  obstructive  pulmonary  disease 
(COPD)  patients.  RESULTS:  The  difference  between  instruments  (SensorMedics  minus  MicroPlus) 
was  statistically  significant  for  FVC  in  all  3  groups  (0.31  L  ±  0.57  in  favor  of  the  SensorMedics)  and 
was  also  significant  for  FEVj  (0.09  L  ±  0.39)  and  PEF  (0.33L/s  ±  0.77)  in  the  asthma  and  COPD 
groups.  Between-group  comparison  of  bias  was  highly  significant  (p  =  0.0001)  for  PEF  when 
comparing  normal  subjects  with  both  obstructive  lung  disease  groups.  We  also  conducted  a  bench 
study  in  which  we  compared  lung  function  from  3  additional  MicroPlus  units  with  the  SensorMedics, 
measuring  FVC  from  a  3-L  syringe  at  several  flow  rates.  A  tendency  to  underestimate  lung  function, 
particularly  at  low  expiratory  flows,  was  noted  in  all  4  MicroPlus  units  tested.  CONCLUSION:  We 
conclude  that  the  MicroPlus  underestimates  lung  function  and,  thus,  the  results  obtained  with  the 
MicroPlus  and  the  desktop  SensorMedics  Vmax22  diagnostic  spirometer  should  not  be  considered 
equivalent  or  interchangeable.  [Respir  Care  1999;44(  12):  1465-1473]  Key  words:  MicroPlus,  Sensor- 
Medics. spirometry,  portable  spirometer,  hand-held  spirometer,  turbine-driven  spirometer. 


Background 

In  recent  years,  a  growing  number  of  portable  spirom- 
eters have  become  available  for  clinical  use.  These  porta- 
ble or  "pocket"  spirometers  offer  potentially  important  ad- 
vantages over  conventional  pulmonary  function  tests 
obtained  in  a  pulmonary  function  laboratory.  The  results 
of  portable  spirometry  can  be  made  available  immediately 
during  an  office  visit.  This  can  have  important  clinical 
implications,  because  the  severity  of  airway  obstruction  is 
often  inaccurately  perceived  by  both  physician  and  patient. 


The  authors  are  affiliated  with  the  Department  of  Medicine,  Pulmonary/ 
Critical  Care  Service,  Madigan  Army  Medical  Center,  Tacoma,  Wash- 
ington. 

The  views  expressed  herein  are  those  of  the  authors  and  do  not  reflect  the 
official  views  of  the  United  States  Army  or  the  Department  of  Defense. 

Correspondence:  LTC  William  E  Caras  MD,  Madigan  Army  Medical 
Center,  ATTN:  MCHJ-MPU.  Tacoma  WA  98433-5000. 


This  lack  of  appreciation  has  been  cited  as  a  risk  factor  for 
fatal  asthma.'  Portable  spirometry  could  also  allow  mea- 
surement of  lung  functions  in  hospitalized  patients  who 
are  too  unstable  for  transport  to  a  pulmonary  function 
laboratory.  In  the  setting  of  occupational  lung  disease, 
portable  spirometry  allows  pulmonary  functions  to  be  inea- 
sured  during  the  critical  time  period  of  environmental  ex- 
posure. Portable  spirometers  could  also  be  used  to  measure 
pulmonary  functions  in  remote  field  settings  that  might 
occur  during  military  deployments  or  during  travel  into 
remote  areas.  If  sufficiently  accurate,  portable  spirometry 
obtained  at  the  time  of  respiratory  symptoms  could  poten- 
tially replace  the  more  cumbersome  provocation  testing 
with  cold  air,  methacholine,  histamine,  or  controlled  ex- 
ercise challenge. 

Before  these  advantages  can  be  fully  realized,  portable 
spirometry  must  prove  to  be  accurate  compared  to  con- 
ventional spirometry  obtained  in  a  pulmonary  function  lab- 
oratory. We  compared  the  performance  of  the  MicroPlus 
portable  spirometer  (Micro  Medical  Instruments,  Roches- 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1465 


Comparison  of  MicroPlus  and  SensorMedics  Vmax22  Spirometers 


ter,  Kent,  United  Kingdom)  with  the  SensorMedics  Vmax22 
diagnostic  spirometer  (SensorMedics,  Loma  Linda,  Cali- 
fornia) currently  used  in  our  pulmonary  function  labora- 
tory. In  order  to  make  our  results  relevant  to  clinical  prac- 
tice, we  studied  a  population  with  lung  function  ranging 
from  normal  to  severely  obstructed.  We  extended  our  as- 
sessment of  the  MicroPlus  spirometer  by  performing  a 
bench  study  utilizing  3  additional  MicroPlus  devices  in 
order  to  evaluate  the  accuracy  of  several  instruments  under 
similar  experimental  circumstances. 


Methods 


Apparatus 


The  portable  MicroPlus  spirometer  contains  a  turbine 
that  generates  rotational  flow  during  the  spirometry  ma- 
neuver. The  flow  drives  a  low-inertia  vane,  the  rotation  of 
which  is  converted  into  electrical  impulses  by  means  of  an 
infrared  light-emitting  diode  and  a  photodiode  sensor.  A 
microprocessor  within  the  housing  converts  the  electrical 
pulses  into  spirometry  measurements  of  forced  vital  ca- 
pacity (FVC),  forced  expiratory  volume  in  the  first  second 
(FEV|),  and  peak  expiratory  flow  (PEF),  which  are 
displayed  digitally.  According  to  product  information 
obtained  from  the  manufacturer  (http://www.micromed. 
co.uk/products/micro.htm)  the  MicroPlus  has  an  accuracy 
of  ±  2%. 

The  SensorMedics  Vmax22  diagnostic  spirometer  uti- 
lizes a  mass  flow  sensor  (two  heated  wires  in  a  wheatstone 
configuration)  to  measure  flow  during  the  FVC  maneuver. 
Flow  across  the  mass  flow  sensor  is  laminar,  and  measured 
resistance  across  the  sensor  is  <  1.5  cm  HjO  at  12  L/s. 
The  SensorMedics  Vmax22  is  flow-calibrated  with  a  3-L 
syringe  injected  at  slow,  medium,  and  fast  flow  rates.  The 
manufacturer  claims  that  the  SensorMedics  device  meets 
the  American  Thoracic  Society  (ATS)  specification  for 
a  diagnostic  spirometer  (±  3%  or  50  mL,  whichever  is 
greater). 2 

For  the  study  protocol,  a  two-way  valve  attached  to 
the  back  of  the  mass  flow  sensor  was  removed  and  the 
MicroPlus  spirometer  was  then  attached  with  a  1.5-inch 
piece  of  rubber  tubing.  In  this  way  the  MicroPlus  was 
attached  in  series  directly  behind  the  SensorMedics  mass 
flow  sensor.  The  two-way  valve  is  used  only  to  deliver 
gases  (carbon  monoxide  and  methane)  used  in  obtaining 
single-breath  diffusion  of  carbon  monoxide  and  resting 
lung-volume  measurements.  Per  discussion  with  the 
SensorMedics  technical  representative,  removal  of  this 
valve  should  not  affect  the  accuracy  of  spirometry  mea- 
surements. A  calibration  check  was  performed  on  the 
MicroPlus  using  a  3-L  syringe  according  to  manufacturer 
recommendations.  Because  the  experiment  involved  a 
change  in  the  SensorMedics  circuit,  the  SensorMedics  was 


calibrated  using  the  same  3-L  syringe  with  the  two-way 
valve  in  place,  with  the  valve  removed,  and  finally  with 
the  valve  removed  and  the  MicroPlus  attached  exactly  as 
used  in  the  study  protocol  (see  below).  In  each  position  the 
SensorMedics  was  found  to  be  highly  accurate  (within  40 
mL  and  ±  1.5%),  easily  meeting  the  ATS  criteria  for 
diagnostic  spirometry  .^ 

Patient  Study 

With  the  MicroPlus  attached,  we  studied  3  groups  of 
patients  by  obtaining  simultaneous  recordings  of  FVC, 
FEV,,  and  PEF.  Group  1  consisted  of  20  subjects  who 
worked  in  the  hospital,  were  nonsmokers,  and  had  no  known 
history  of  lung  disease.  Group  2  consisted  of  20  patients 
with  the  clinical  diagnosis  of  asthma,  selected  from  asthma 
clinic  when  the  treating  physician  ordered  routine  spirom- 
etry. Patients  in  Group  2  were  accepted  if  their  previously- 
known  FEVi  was  50-80%  of  predicted.  Group  3  con- 
sisted of  an  additional  20  patients,  each  with  the  clinical 
diagnosis  of  chronic  obstructive  pulmonary  disease 
(COPD).  These  patients  were  accepted  if  their  previously- 
known  FEV,  was  <  50%  of  predicted.  All  patients  per- 
formed a  minimum  of  3  forced  expiratory  maneuvers  that 
satisfied  ATS  criteria  for  acceptability  and  reproducibili- 
ty.^  The  protocol  was  conducted  in  accordance  with  the 
ethical  standards  of  the  World  Medical  Association  Dec- 
la  ration  of  Helsinki .  ^ 

Bench  Study 

Following  completion  of  the  study  protocol,  we  system- 
atically performed  a  calibration  check  on  the  MicroPlus 
spirometer  used  in  this  study  (MicroPlus  K4574)  and  3 
other  MicroPlus  units  (MicroPlus  K5356,  MicroPlus 
K5354,  and  MicroPlus  K5355)  available  in  our  depart- 
ment. The  bench  study  was  designed  to  determine  whether 
all  MicroPlus  devices  tended  to  underestimate  lung  func- 
tions as  did  the  device  (MicroPlus  K4574)  used  in  the 
study  protocol,  and  whether  the  experimental  design  con- 
tributed to  the  underestimation  of  the  SensorMedics  stan- 
dard. Each  unit  was  tested  with  the  same  3-L  syringe.  A 
total  of  15  syringe  injections  were  conducted;  5  each  at 
slow,  medium,  and  fast  flows.  Slow  flows  were  obtained 
by  emptying  the  syringe  in  >  6  seconds,  medium  flows 
were  obtained  by  emptying  the  syringe  in  2-4  seconds, 
and  fast  flows  were  obtained  by  emptying  the  syringe  in 
<  1  second.  Each  MicroPlus  unit  was  then  placed  in  series 
with  the  SensorMedics,  exactly  as  in  the  study  protocol. 
The  3-L  syringe  was  attached  to  the  SensorMedics  mouth- 
piece and  an  identical  series  of  1 5  syringe  injections  were 
conducted,  simultaneously  recording  the  MicroPlus  and 
SensorMedics  values.  One  researcher  (Reasor)  performed 
all  the  measurements. 


1466 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Comparison  of  MicroPlus  and  SensorMedics  Vmax22  Spirometers 


Analysis 

The  spirometry  data  were  analyzed  by  graphically  plot- 
ting the  FEV|,  FVC,  and  PEF  values  obtained  by  the 
MicroPlus  (as  the  dependent  variable)  against  the  FEV,, 
FVC,  and  PEF  values  obtained  by  the  SensorMedics.  Each 
value  represents  the  single  highest  FVC,  FEV,,  and  PEF, 
and  is  graphically  plotted  with  an  identity  line  allowing  the 
relative  differences  between  the  two  instruments  to  be  ap- 
preciated visually.  Agreement  between  instruments  was 
analyzed  by  statistical  methods  proposed  by  Bland  and 
Altman-*  in  which  the  mean  of  the  measures  of  the  two 
instruments  was  taken  as  the  independent  variable  and 
plotted  against  the  differences  between  the  two  instru- 
ments (SensorMedics  minus  MicroPlus).  The  mean  of  the 
differences  between  instruments  was  taken  as  bias.  The 
standard  deviation  of  the  differences  was  taken  as  a  mea- 
sure of  instrument  precision.  Limits  of  agreement  (LOA) 
were  obtained  by  calculating  the  mean  ±  2  standard  de- 
viations. The  paired  t  test  was  used  to  assess  between- 
instrument  differences,  with  significance  at  p  <  0.05.  In- 
ter-group comparison  of  bias  for  all  3  parameters  was 
analyzed  with  Fisher's  protect  least  square  difference  test, 
with  significance  at  p  <  0.05. 

Differences  in  measured  syringe  volume  obtained  in  the 
bench  study  were  analyzed  using  the  unpaired  t  test,  with 


significance  at  p  <  0.05.  Accuracy  in  the  bench  study  was 
calculated  as  the  ±  percent  difference  from  the  3-L  sy- 
ringe volume. 

Results 

A  total  of  60  adult  patients  (33  men  and  27  women) 
were  evaluated.  The  spirometry  data  given  below  were 
obtained  with  the  SensorMedics  diagnostic  spirometer  ac- 
cording to  ATS  criteria.- 

Group  1  consisted  of  12  males  and  8  females,  age  23-81 
years,  who  volunteered  to  participate  in  pulmonary  func- 
tion testing  and  were  found  to  have  normal  spirometry 
results.  In  Group  1,  average  FEV,  was  3.41  L  (range  of 
1.98-5.35  L),  average  FVC  was  3.99  L  (range  of  2.16- 
6.45  L),  and  average  PEF  was  8.83  L/s  (range  of  5.28- 
13.95  L/s). 

Group  2  consisted  of  7  male  and  1 3  female  asthmatics, 
age  25-78  years,  in  which  average  FEV,  was  1 .75  L  (range 
of  0.95-3.01  L),  average  FVC  was  2.37  L  (range  of  1.08- 
4.13  L),  and  average  PEF  was  4.97  L/s  (range  of  2.35- 
10.80  L/s). 

Group  3  consisted  of  14  male  and  6  female  COPD  pa- 
tients, age  45-80  years,  in  which  average  FEV,  was  1.01 
L  (range  of  0.41-2.72  L),  average  FVC  was  2.10  L  (range 


•  Normal 
o  Asthma 
A  COPD 


0  12  3  4  5 

Sensormedlcs  (L) 

Fig.  1 .  Forced  vital  capacity  (FVC)  readings  from  the  SensorMedics  Vmax22  diagnostic  spirometer  and 
the  MicroPlus  portable  spirometer  (Microspirometer)  (see  text  for  explanation  and  discussion). 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1467 


Comparison  of  MicroPlus  and  SensorMedics  Vmax22  Spirometers 


u 

/ 

•  r" 

5 

S     ' 

k_ 

.'■ 

s 

,'■•• 

0 

E 

,.•' 

O      3 

'i    o 

£1 

•'  8* 

Q. 

ji»° 

W 

'• 

O 

.• 

O 

,.^^ 

^      2 

_^ 

Ok 

1 

=°       o       ^ 

0' 

'■' 

•  Normal 
o  Asthma 
aCOPD 


Sensormedics  (L) 

Fig.  2.  Forced  expiratory  volume  in  the  first  second  (FEV,)  readings  from  the  SensorMedics  Vmax22 
diagnostic  spirometer  and  the  MicroPlus  portable  spirometer  (Microspirometer)  (see  text  for  expla- 
nation and  discussion). 


of  0.71-4.02  L),  and  average  PEF  was  2.97  L/s  (range  of 
1.02-9.55  L/s). 

Figures  1,  2,  and  3  show  plots  of  the  values  obtained 
with  the  MicroPlus  (y-axis)  and  the  SensorMedics  (x- 
axis).  The  data  points  are  plotted  about  a  line  of  identity. 
A  clear  linear  relationship  was  found  between  the  Micro- 
Plus  and  SensorMedics  for  all  3  parameters  tested  (FVC, 


r  =  0.9975;  FEV,,  r  =  0.9886;  and  PEF, 


0.9968). 


Close  examination  of  Figures  2  and  3  reveals  that  the  data 
points  for  Groups  2  and  3  fall  consistently  below  the 
identity  line  for  both  FEV,  and  PEF.  For  FVC  (see  Fig, 
1),  nearly  all  the  data  points  fall  below  the  line  of  identity. 
This  represents  a  consistent  underestimation  of  pulmo- 
nary function  values  by  the  Microplus  compared  to  the 
SensorMedics. 

The  differences  between  instruments  were  examined  us- 
ing Bland-Altman  analysis.  In  Figures  4,  5,  and  6,  for  each 
patient  the  average  value  of  the  two  instruments  is  plotted 
along  the  x-axis  and  the  actual  differences  between  the 
SensorMedics  and  MicroPlus  are  plotted  along  the  y-axis. 
The  mean  of  the  differences  or  bias  is  plotted  as  a  dotted 
horizontal  line  along  with  the  respective  LOA,  defined 
as  ±  2  standard  deviations.  Finally,  a  solid  "zero"  line  is 
plotted  to  serve  as  a  convenient  reference  point.  Underes- 
timation of  FVC  by  the  MicroPlus  is  graphically  portrayed 
in  Figure  4,  which  shows  nearly  all  data  points  for  FVC 


falling  above  the  zero  line.  This  appears  especially  true  for 
patients  with  lower  FVC  (Groups  2  and  3).  Bland-Altman 
analysis  for  FEV,  (see  Fig.  5)  shows  a  small  bias  and  a 
distribution  of  data  points  scattered  about  the  bias  line.  For 
PEF  (see  Fig.  6)  the  individual  data  points  on  the  Bland- 
Altman  graph  show  consistent  underestimation  of  flows  in 
both  obstructive  lung  disease  groups  (Groups  2  and  3), 
whereas  there  is  overestimation  of  PEF  in  some  of  the 
normal  subjects.  Quantitatively,  the  bias  for  FVC  was 
0.3 1  ±  0.29  L,  with  LOA  ranging  from  -0.3 1  L  to  0.88  L. 
The  instrument  bias  for  FEV,  was  0.09  ±  0.20  L,  with 
LOA  ranging  from  -0.29  L  to  0.47  L.  For  PEF  the  bias 
was  0.33  ±  0.38  L/s,  with  LOA  ranging  from  -0.441  L/s 
to  1.099  L/s. 

For  all  subjects  (n  =  60),  between-instrument  bias  was 
statistically  significant  for  FVC  (p  <  0.001),  FEV,  (p  < 
0.001),  and  PEF  (p  =  0.001).  Subgroup  analysis  (Table  1) 
revealed  no  significant  between-instrument  difference  for 
FEV,  or  PEF  in  normal  subjects  (Group  1).  Significant 
differences  were  found  for  FVC  in  each  group  and  for  both 
FEV,  and  PEF  in  Groups  2  and  3.  To  determine  whether 
these  numerical  differences  were  uniform  across  all  sub- 
ject groups,  we  used  the  Fischer  protect  least  square  dif- 
ference test  to  evaluate  the  statistical  significance  of  be- 
tween-group  bias.  These  data  are  shown  in  Table  2.  The 
differences  in  bias  for  FEV,  between  Group  1  and  Group 


1468 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Comparison  of  MicroPlus  and  SensorMedics  Vmax22  Spirometers 


lb 
14 

12 

• 

^^ 

/ 

in 

P 

J 

10  ^ 

j_ 

*- 

0) 

»' 

di 

.'■  • 

fc 

«  - 

.-■ 

y 

••' 

• 

Q. 

4^ 

b 

6 

,.,» 

:s 

4 
2 

../* 

„4^ 

'a* 

,->* 

.-■  * 

n  - 

-■' 

•  Nomnal 
D  Asthma 
*COPD   1 


10 


12 


14 


Sensormedics  (Us) 


Fig.  3.  Peak  expiratory  flow  (PEF)  readings  from  the  SensorMedics  Vmax22  di- 
agnostic spirometer  and  the  MicroPlus  portable  spirometer  (Microspirometer) 
(see  text  for  explanation  and  discussion). 


0) 

Q) 

E 

o 

1 

Q. 

in 

() 

O 

> 

o 

U- 

^ 

c 

(A 

f  1 

3 

c 

>-    o 

m  — 
S  <D 
Q     E 

o 

(0 

c 
<1> 

CO 


1.0 


0.8 


0.6 


0.4 


0.2 


0.0 


-0.2 


-0.4 


-0.6 


-0.8 


D 


D 


A  •  °  ° 

^  A*  • 


+  0.881  (+2  sd) 


Mean 

=  0.31 

•  Normal 

D  Asthma 
aCOPD 

-0.31  (-; 

sd) 

0  1  2  3  4  5  6  7 

Mean  FVC  for  Both  Instruments  (L) 

Fig.  4.  Bland-Altman  analysis  of  forced  vital  capacity  (FVC)  values  (see  text  for  explanation  and  discussion). 


2  approached  statistical  significance,  with  a  p  value  of 
0.051.  Between-group  comparisons  of  bias  did  not  reach 
statistical  significance  for  FVC  in  any  group  (see  Table  2). 
Significant  differences  in  PEF  were  found  between  Groups 


1  and  2,  and  between  Groups  1  and  3,  but  not  between 
Groups  2  and  3. 

We  performed  a  bench  study  using  the  protocol  Micro- 
Plus  spirometer  (K4574)  and  3  other  Microplus  devices 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1469 


Comparison  of  MicroPlus  and  SensorMedics  Vmax22  Spirometers 


1.2 

1.1 

1 

03 

0.9 

(1) 

F 

U.8 

o 

_l 

Q. 

0.7 

T- 

n 

OH 

> 

o 

2 

US 
u. 

0.5 

■s 

3 

0.4 

03 

C 

O 

r 

E 

0.3 

0) 

o 

0.2 

!t 

0) 

Q 

b 

o 

0.1 

u> 

0 

c 

(I) 

O) 

-0.1 
-0.2 
-0.3 
-0.4 

>  °    n  D  • 


n    •• 


+0.47  (+2  sd) 


•  Normal 
a  Asthma 
aCOPD 


Mean  =  0.09 


-0.29  (-2  sd) 


0  12  3  4  5  6 

Mean  FEV1  for  both  Instruments  (L) 

Fig.  5.  Bland-Altman  analysis  of  forced  expiratory  volume  In  the  first  second  (FEV,)  values  (see  text  for  explanation 
and  discussion). 


(MicroPlus  K5356,  MicroPlus  K5354,  and  MicroPlus 
K5355)  available  in  our  department.  Table  3  shows  data 
from  each  of  the  4  devices  studied.  The  values  shown  are 
the  numerical  average  of  five  3-L  syringe  calibration  checks 
obtained  at  slow,  medium,  or  fast  flow  (see  Methods  sec- 
tion), and  the  corresponding  standard  deviations,  absolute 
difference  from  the  ideal  3-L  syringe  volume,  and  accu- 
racy are  given  in  the  adjacent  columns.  Each  device  was 
tested  individually  and  in  series  with  the  SensorMedics 
spirometer,  as  in  the  patient  protocol.  With  the  MicroPlus 
attached  in  series,  the  SensorMedics  slightly  underesti- 
mated the  3-L  syringe  volume  at  slow  (2.967  L,  -1.1%), 
medium  (2.935  L,  -2.2%).  and  fast  (2.947  L,  -1.8%)  flow 
rates,  but  still  fell  within  the  diagnostic  accuracy  specifi- 
cation for  a  diagnostic  spirometer  (±  3%  or  50  mL,  which- 
ever is  greater).-  The  device  used  in  our  study  (Microplus 
K4574)  underestimated  the  3-L  syringe  volume  at  slow 
flow  rates  when  tested  alone  (2.776  L,  -7.5%)  or  in  series 
(2.734  L,  -8.9%).  The  tendency  to  underestimate  syringe 
volume  was  also  seen  at  medium  flow  rates  (2.900  L, 
-3.3%)  both  alone  and  in  series.  At  fast  flows  the  Micro- 
Plus  K4574  proved  to  be  highly  accurate  (2.976  L.  0.8%, 
alone,  and  3.010  L,  +0.3%,  in  series).  Combined  data  for 
all  4  MicroPlus  devices  showed  significant  underestima- 
tion of  the  3-L  syringe  volume  at  low  flow  rates  (2.816  L, 
-6.1%,  alone,  and  2.750  L,  -8.2%,  in  series).  At  medium 
flows  the  underestimation  of  3-L  syringe  volume  was  2.904 


L  (-3.2%)  alone,  and  2.869  L  (-4.4%)  in  series.  No  ten- 
dency to  underestimate  syringe  volume  was  seen  at  fast 
flow  rates  (3.027  L,  +0.9%,  alone,  and  3.003  L,  +0.1%, 
in  series).  Accuracy  data  are  given  for  each  spirometer  in 
Table  3.  The  ATS  threshold  criteria  for  diagnostic  spirom- 
eters is  ±  3%  or  50  mL,  whichever  is  greater,  and  the 
criteria  for  monitoring  devices  is  ±  5%  or  100  mL,  which- 
ever is  greater.-  So,  with  a  3-L  syringe  the  maximum 
deviation  allowed  is  90  mL  for  a  diagnostic  spirometer  and 
150  mL  for  a  monitoring  spirometer.  None  of  the  Micro- 
Plus  devices  met  threshold  criteria  for  either  diagnostic  or 
monitoring  spirometers  at  slow  flow  rates,  but  at  fast  flows 
the  90  mL  standard  for  diagnostic  spirometry  was  met.  At 
medium  flows  only  two  devices  met  the  90  mL  threshold 
(MicroPlus  K5356  in  series  and  MicroPlus  K5354  alone). 
All  devices  were  within  the  150  mL  standard  at  medium 
flows.  The  SensorMedics  Vmax22  met  threshold  criteria 
overall  for  diagnostic  spirometry  at  slow,  medium,  and 
fast  flows.  However,  it  failed  the  90  mL  standard  when 
placed  in  series  with  the  MicroPlus  K5355  at  medium  and 
fast  flows. 

Table  3  also  shows  the  values  for  the  unpaired  t  test 
comparing  measured  syringe  volume  obtained  by  each 
MicroPlus  device  alone  (MPA)  versus  the  value  obtained 
by  the  MicroPlus  in  series  with  the  SensorMedics  (MPS). 
An  unpaired  /  test  was  also  calculated  for  the  measured 
syringe  volume  between  the  SensorMedics  in  series  (SMS) 


1470 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Comparison  of  MicroPlus  and  SensorMedics  Vmax22  Spirometers 


0) 


1.2 
1 
0.8 
0.6 
0.4 
0.2 
0 
-0.2 


"-  O 
UJ  ~ 
Q.   2 

O    3 

o  .E 
^  E 
£   o 

0    T3 

o 

«      -0.6 

c 

0) 

-1 

-1.2 


A  A 
A 


A  A 


CP 


•  / 


□     • 


+1.099  (+2  sd) 


Mean  =  0.329 


I   •  Normal 

D  Asthma 

aCOPD 

-0.441  (-2  sd) 


14 


16 


0  2  4  6  8  10  12 

Mean  PEF  in  both  Instruments  (Us) 

Fig.  6.  Bland-Altman  analysis  of  peal<  expiratory  flow  (PEF)  values  (see  text  for  explanation  and  discussion). 


Table  1 .      Comparison  of  Bias  and  Precision* 


Table  2.      Between-Group  Comparison  of  Bias 


Lung 
function 


Bias  ±  SD 


p  value 


Group  1  (Normal) 

FEV,  (L) 

0.02  ±0.15 

0.605  (ns) 

FVC  (L) 

0.22  ±0.17 

<  0.001 

PEF  (L/s) 

0.06  ±  0.42 

0.950  (ns) 

Group  2  (Asthma) 

FEV,  (L) 

0.14  ±0.17 

0.002 

FVC  (L) 

0.39  ±  0.27 

<  0.001 

PEF  (Us) 

0.45  ±  0.20 

<  0.001 

Group  3  (COPD) 

FEV,  (L) 

0.11  ±0.24 

0.048 

FVC  (L) 

0.32  ±  0.37 

0.001 

PEF  (L/s) 

0.53  ±  0.28 

<  0.001 

All  Groups 

FEV,  (L) 

0,09  ±  0.20 

0.001 

FVC  (L) 

0.31  ±  0.29 

<  0.001 

PEF  (L/s) 

oPlus;  bias  =  mean,  r 

0.33  ±  0.38 

recision  -  standard  devial 

<  0.001 

*SensorMedics  minus  Mic 

on  (SD). 

FEV,  -  forced  expiralory  volume  in  the  first  second. 

FVC  =  forced  vital  capacity. 

PEF  =  peak  expiratory  flow. 

COPD  -  chrunic  obstructive  pulmonary  disease. 


versus  the  MPS,  and  the  SMS  versus  the  MPA.  Significant 
differences  in  measured  syringe  volume  were  found  be- 
tween the  SensorMedics  and  the  MicroPlus  alone  (SMS  vs 
MPA)  and  in  series  (MPS  vs  SMS).  The  combined  data 
were  highly  significant  at  slow,  medium,  and  fast  flows 
(p  <  0.01).  However,  individual  MicroPlus  devices  did 


Lung 
Function 


Groups 


Mean 
Difference 


Critical 
Difference 


FEV, 


FVC 


PEF 


p  value 


Group  1 

Group  2 

-0.121 

0.122 

0.051 

Group  1 

Group  3 

-0.095 

0.122 

0.122 

Group  2 

Group  3 

0.025 

0.122 

0.677 

Group  1 

Group  2 

-0.169 

0.179 

0.063 

Group  1 

Group  3 

-0.097 

0.179 

0.285 

Group  2 

Group  3 

0.073 

0.179 

0.417 

Group  1 

Group  2 

-0.448 

0.198 

<  0.0001* 

Group  1 

Group  3 

-0.519 

0.198 

<  0.0001* 

Group  2 

Group  3 

-0.071 

0.198 

0.475 

FEV,  =  forced  expiratory  volume  in  the  first  second, 

FVC  -  forced  vital  capacity, 

PEF  -  peak  expiratory  flow, 

*p  value  <  0,05  using  Fisher's  protect  least  square  difference  test. 


vary  somewhat.  The  study  device  (MicroPlus  K4574)  had 
a  p  value  of  0.05  at  medium  flow  rates  (MPS  vs  SMS)  and 
p  values  of  0.07  (MPS  vs  SMS)  and  0.43  (MPA  vs  SMS) 
at  fast  flow  rates.  Nonsignificant  differences  were  also 
found  for  the  MicroPlus  K5355  at  both  medium  (MPS  vs 
SMS,  and  MPA  vs  SMS)  and  fast  flows  (MPS  vs  SMS). 
Finally,  nonsignificant  p  values  were  found  for  the  K5354 
at  medium  flows  (MPA  vs  SMS)  and  for  the  MicroPlus 
K5356  at  medium  flows  (MPS  vs  SMS).  At  slow  flows  all 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1471 


Comparison  of  MicroPlus  and  SensorMedics  Vmax22  Spirometers 


Table  3.      Calibration  Study  (3.0  L)  of  4  MicroPlus  Devices 


Cal 

MicroPlus  alone  (MPA) 

MicroPlus 

in  series 

(MPS) 

SensorMedics  in  series  (SMS) 

p  value 

Mean 

SD 

DifP 

Accuracyt 

(±  %) 

Mean 

SD 

Ditf* 

Accuracyt 
(±  %) 

Mean 

SD 

Diff 

Accuracyt 

(±  %) 

MPA  vs 
MPS 

MPS  vs 
SMS 

MPA  vs 
SMS 

K5356 

Slow 

2.8.12 

0.041 

0.168 

5.6 

2.758 

0.013 

0.242 

8.1 

2.982 

0.047 

0.018 

0.6 

0.0  |t 

<0.01t 

<0.01t 

Med 

2.902 

0.037 

0.098 

3.3 

2.928 

0.027 

0.072 

2.4 

2.9.56 

0.018 

0.(M4 

1.5 

0.24 

0.09 

0.03t 

Fast 

.1.042 

0.021 

-0.042 

1.4 

3.012 

0.022 

-0.012 

0.4 

2.966 

0.015 

0.034 

I.I 

0.06 

<0.0|t 

<O.OIt 

K5354 

SUtw 

2.836 

0.073 

0.164 

5.5 

2.812 

0.013 

0.188 

6.3 

2.952 

0.022 

0.048 

1.6 

0.51 

<0.0|t 

0.02t 

Med 

2.924 

0.044 

0.076 

2.5 

2.862 

0.016 

0.138 

4.6 

2.960 

0.017 

0.040 

1.3 

0.03  ± 

<O.OIt 

0.15 

Fast 

3.046 

0.013 

"0.046 

1.5 

3.048 

0.015 

-0.048 

1.6 

2.970 

0.0.10 

0.030 

1.0 

0.83 

<  O.Olt 

<0.0lt 

K4574§ 

Slow 

2.776 

0.091 

0.224 

7.5 

2.7.14 

0.036 

0.266 

8.9 

2.958 

0.029 

0.042 

1.4 

0.38 

<0.01t 

<0.0lt 

Med 

2.9CX) 

0.012 

O.KX) 

3.3 

2.9(K) 

0.030 

0.100 

3.3 

2.940 

0.024 

0.060 

2.0 

1.0 

0.05 

0.0  It 

Fast 

2.976 

0.020 

0.024 

0.8 

3.010 

0.007 

-0.010 

0.3 

2.956 

0.048 

0.044 

1.5 

0.0  It 

0.07 

0.43 

K5355 

Slow 

2.820 

0.032 

0.180 

6.0 

2.712 

0.072 

0.288 

9.6 

2.976 

0.064 

0.024 

0.8 

0.()3t 

<  .0|t 

<O.OIt 

Med 

2.889 

0.0.50 

0.1 11 

3.7 

2.784 

0.088 

0.216 

7.2 

2.884 

0.025 

0.116 

3.9 

0.06 

0.06 

0.88 

Fast 

3.044 

0.01.5 

-0.044 

1.5 

2.942 

0.(X)3 

0.058 

1.9 

2.896 

0.067 

0.104 

3.5 

0.02t 

0.29 

<0.01t 

All  (n  = 

20) 

Slow 

2.816 

0.063 

0.184 

6.1 

2.754 

0.054 

0.246 

8.2 

2.967 

0.042 

0.033 

1.1 

<  0.0 It 

<  0.0 It 

<O.OIt 

Med 

2.904 

0.038 

0.096 

3.2 

2.869 

0.072 

0.131 

4.4 

2.935 

0.037 

0.065 

2  2 

0.06 

<  0.0 It 

0.0  It 

Fast 

3.027 
nge. 

0.034 

-0.027 

0.9 

3.003 

0.050 

-0.003 

0.1 

2.947 

0.051 

0.053 

1.8 

0.09 

<o.oit 

<O.OIt 

•Diffcrcn 

ee  I'roin 

.1-L  syri 

tSee  lexl  for  ATS  criteria 

for  diagnostic  and 

monitoring  sp 

iromctry. 

Xp  value 

<  0.1)5  1 

jiipaircd 

;  test. 

§Sludy  deviLC. 

SD  ^  standard  dt 

aviation. 

4  MicroPlus  devices  showed  significant  differences  from 
the  SensorMedics  value,  whether  measured  alone  or  in 
series.  Differences  in  measured  syringe  volume  between 
MPA  and  MPS  were  usually  not  significant.  However, 
significant  differences  were  found  for  the  MicroPlus  K5356 
and  the  MicroPlus  K5355  at  slow  flows,  for  the  MicroPlus 
K5354  at  medium  flows,  and  for  the  MicroPlus  K4574  at 
fast  flows.  Significant  overall  differences  were  found  for 
MPA  versus  MPS  at  slow  flows  only. 

Discussion 

Our  study  assessed  the  performance  of  the  MicroPlus 
portable  spirometer  against  the  SensorMedics  Vmax22  di- 
agnostic spirometer  during  simultaneous  measurements  of 
FVC,  FEV|  and  PEF.  Though  the  results  show  a  high 
degree  of  correlation  between  the  devices,  important  dif- 
ferences emerged.  The  MicroPlus  showed  a  consistent  ten- 
dency to  underestimate  FVC,  leading  to  significant  be- 
tween-instrument  differences  in  all  groups  studied. 
Significant  between-instrument  differences  were  also  seen 
in  the  obstructive  lung  disease  groups  (Groups  2  and  3)  for 
both  FEV|  and  PEF.  Between-group  differences  in  bias 
were  of  borderline  significance  between  Groups  1  and  2 
for  FEV|  (p  =  0.051),  but  were  highly  significant  between 
Groups  1  and  2  and  Groups  1  and  3  for  PEF  (see  Table  2). 
The  bias  in  FVC  showed  no  significant  difference  between 
subject  groups.  The  underestimation  of  FVC  (0.3 1  L)  ap- 


pears large  enough  to  be  deemed  clinically  significant. 
Although  the  bias  in  FEV,  is  quantitatively  smaller  (0.09 
L),  it  increases  to  0.14  L  in  Group  2  and  0.1 1  L  in  Group 
3.  The  bias  in  PEF  showed  a  similar  tendency.  These 
results  suggest  that  the  MicroPlus  underestimates  FVC 
and  shows  increasing  bias  for  FEV,  and  PEF  in  the  setting 
of  airway  obstruction. 

Our  study  design  allowed  the  MicroPlus  and  the 
SensorMedics  to  measure  lung  functions  simultaneously 
during  the  same  expiratory  maneuver.  In  this  manner  we 
eliminated  the  confounding  effects  of  variable  patient  ef- 
forts. Our  study  population  consisted  of  patients  whose 
underlying  lung  function  varied  from  normal  to  severely 
obstructed.  This  enabled  us  to  compare  the  performance  of 
the  MicroPlus  spirometer  over  a  wider  range  of  expiratory 
volumes  and  flows  than  studies  using  only  normal  subjects. 

There  are  several  limitations  in  our  study.  Theoretically, 
placing  the  MicroPlus  device  in  series  behind  the  Sensor- 
Medics could  contribute  to  error  because  the  expired  gas 
must  traverse  the  mass  flow  sensor  before  reaching  the 
MicroPlus.  However,  because  flow  is  laminar  through  the 
mass  flow  sensor,  the  effects  of  any  downstream  turbu- 
lence or  resistance  should  be  minimal.  Even  so,  placing 
the  MicroPlus  in  series  behind  the  flow  sensor  does  alter 
the  native  circuit,  so  a  sight  alteration  in  flow  character- 
istics cannot  entirely  be  ruled  out.  In  retrospect,  it  would 
have  been  useful  to  study  the  effects  of  placing  the 
MicroPlus  both  in  front  of  and  behind  the  mass  flow  sen- 


1472 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Comparison  of  MicroPlus  and  SensorMedics  Vmax22  Spirometers 


sor  to  study  the  effects  on  measured  syringe  volume.  An- 
other drawback  with  this  study  was  that  the  patient  proto- 
col utilized  only  one  MicroPlus  spirometer  (MicroPlus 
K4574).  Thus,  one  could  argue  that  the  results  might  not 
apply  to  all  MicroPlus  devices. 

The  bench  study  allowed  us  to  examine  some  of  the 
latter  concerns.  As  seen  in  Table  3,  all  4  of  the  MicroPlus 
instruments  underestimated  the  3-L  syringe  volume  at  low 
flows  and  were  highly  accurate  at  fast  flows,  whether  the 
calibration  check  was  performed  alone  or  in  series  with  the 
SensorMedics.  These  observations  suggest  that  the  patient 
protocol  device  (MicroPlus  K4574)  was  not  unique  in  its 
performance  characteristics.  The  bench  study  did  show  a 
small  (0.06  L)  overall  difference  at  slow  flow  rates  be- 
tween the  MPA  and  the  MPS,  which  was  statistically  sig- 
nificant. However,  these  values  were  obtained  during  sep- 
arate syringe  injections,  so  the  measurements  were  not 
simultaneous.  Although  this  small  0.06  L  difference  does 
suggest  that  placing  the  MicroPlus  in  series  may  contrib- 
ute to  an  underestimation  of  lung  function,  we  do  not  feel 
this  difference  can  explain  the  large  between-device  dif- 
ferences observed  in  the  patient  protocol.  For  example,  the 
bias  noted  between  instruments  in  the  patient  study  was 
0.3 1  L  for  FVC.  Also,  the  device  used  in  the  patient  pro- 
tocol (MicroPlus  K4574)  showed  no  significant  changes  in 
syringe  volume  in  series  versus  alone  (MPA  vs  MPS), 
except  at  high  flow  rates,  where  it  actually  overestimated 
the  3-L  syringe  volume  when  placed  in  series.  Thus,  the 
results  of  the  patient  protocol  that  utilized  device  Micro- 
Plus  K4574  cannot  be  attributed  to  experimental  design. 

One  of  the  unexpected  results  of  the  bench  study  was 
that  none  of  the  MicroPlus  devices  tested  met  the  ATS 
criteria  for  diagnostic  or  monitoring  spirometry  when  tested 
at  slow  flows,  yet  all  easily  passed  at  fast  flows.  These 
results  confirm  that  the  protocol  device  (MicroPlus  K4574) 
was  not  unique  in  its  tendency  to  underestimate  lung  func- 
tion. Furthermore  the  high-percentage  error  at  low  flows 
appear  to  substantiate  the  findings  of  the  patient  protocol, 
in  which  increasing  between-instrument  bias  was  found 
with  both  of  the  obstructive  lung  disease  groups.  Most 
importantly,  the  results  of  the  bench  study  emphasize  the 
absolute  need  to  test  spirometers  at  both  fast  and  slow  flow 
rates,  as  suggested  in  the  ATS  guideline.-  Our  approach  of 
testing  the  MicroPlus  devices  after  the  patient  protocol  {in 
reverse)  was  based  on  the  manufacturer's  claimed  accu- 
racy of  ±  2%. 

The  MicroPlus'  tendency  to  underestimate  lung  func- 
tions has  been  noted  by  other  investigators  who  studied  the 


Micro  Spirometer  (an  earlier  model  of  the  MicroPlus)  and 
other  turbine-driven  portable  spirometers.''-^  Presumably, 
turbine-driven  spirometers  have  difficulty  sensing  low  flow 
near  the  end  of  the  FVC  maneuver,  which  is  characteristic 
of  patients  with  airway  obstruction.  Indeed,  our  techni- 
cians often  noted  the  MicroPlus  device  "shutting  off  dur- 
ing the  last  several  seconds  of  the  expiratory  maneuver  in 
the  patient  protocol. 

Conclusions 

Our  study  extended  the  clinical  experience  with  turbine- 
driven  spirometers  by  studying  the  MicroPlus  in  a  group 
of  patients  whose  lung  function  ranged  from  normal  to 
severely  obstructed.  We  found  significant  between-group 
differences  in  bias  for  PEF  when  comparing  the  normal 
(Group  1)  patients  with  the  obstructive  lung  disease  pa- 
tients. Thus,  the  degree  of  underestimation  of  PEF  by  the 
MicroPlus  may  increase  in  the  setting  of  airway  obstruc- 
tion. Our  data  suggest  that  this  underestimation  may  also 
occur  with  FEV,,  though  the  critical  threshold  for  signif- 
icance was  not  reached  in  this  study.  Because  our  patient 
protocol  utilized  only  one  MicroPlus  device,  we  recom- 
mend further  studies  be  done  with  patients  with  various 
levels  of  lung  function.  For  now,  we  feel  the  MicroPlus 
spirometer  should  not  be  considered  equivalent  to  or  in- 
terchangeable with  a  diagnostic  spirometer  such  as  the 
SensorMedics  Vmax22. 


REFERENCES 

Boulet  LP.  Deschesnes  F,  Turcotte  H,  Gignac  F.  Near-fatal  asthma: 
clinical  and  physiologic  features,  perception  of  bronchoconstriction 
and  physiologic  profile.  J  Allergy  Clin  Immunol  I99l;88(6):838- 
846. 

American  Thoracic  Society.  Standardization  of  spirometry,  1994  up- 
date. Am  J  Respir  Crit  Care  Med  I99.');I52(3):1 107-1 136. 
World  Medical  Association  Declaration  of  Helsinki.  Recommenda- 
tions guiding  physicians  in  biomedical  research  involving  human 
subjects.  Respir  Care  l997:42(6):635-636. 

Bland  JM,  Altman  DO.  Statistical  methods  for  assessing  agreement 
between  two  methods  of  clinical  measurement.  Lancet  1986:1(8476): 
307-310. 

Nelson  SB  Gardner  RM,  Crapo  RO.  Jensen  RL.  Performance  eval- 
uation of  contemporary  spirometers.  Chest  1990:97(2):288-297. 
Gunawardena  KA.  Houston  K,  Smith  AP.  Evaluation  of  the  turbine 
pocket  spirometer.  Thorax  l987;42(9):689-693. 
Ng  TP,  Tan  WC,  Hui  KP.  Ventilatory  function  measured  with  the 
Micro  Spirometer:  performance  evaluation  and  reference  values.  Ann 
Acad  Med  Singapore  I995:24(3):403^10. 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1473 


In  Vitro  Testing  of  MDI  Spacers:  A  Technique  for  Measuring 

Respirable  Dose  Output  with  Actuation  In-Phase  or 

Out-of-Phase  with  Inhalation 

Scott  A  Foss  and  Jean  W  Keppel  PhD 


BACKGROUND:  Many  studies  have  reported  that  users  of  metered  dose  inhalers  (MDIs)  have 
difficulty  in  coordinating  inhalation  with  actuation  of  the  MDI  canister.  The  purpose  of  this  study 
was  to  determine  how  a  lack  of  coordination  affects  the  respirable  dose  delivered  to  the  patient's 
lungs  when  an  MDI  spacer  or  chamber  is  used.  Measuring  respirable  dose  (the  dose  in  the  1-5  ftm 
particle  size  range)  requires  the  use  of  a  cascade  impactor  or  other  particle  sizer.  However,  a 
cascade  impactor  requires  a  constant  flow  rate.  This  would  appear  to  be  incompatible  with  a  study 
of  coordination,  which  requires  a  variable  flow  rate  to  simulate  the  patient's  breathing  through  the 
MDI  device.  METHODS:  We  describe  herein  a  new  variable  flow  rate  technique  for  measuring 
particle  sizes  and  dose  output  with  a  cascade  impactor  (with  a  constant  flow  rate),  while  simulta- 
neously using  a  breathing  machine  to  regulate  the  flow  of  aerosol  medication  through  an  MDI 
device  and  throat  model.  Using  this  technique,  we  tested  4  hand-held  MDI  devices:  the  Airlife 
Hand-Held  MediSpacer,  the  Aerosol  Cloud  Enhancer  (ACE),  the  OptiHaler,  and  the  AeroCham- 
ber.  Each  device  was  tested  under  two  different  conditions:  (a)  in-phase,  in  which  the  MDI  drug 
canister  (Ventolin)  is  actuated  at  the  start  of  inhalation,  and  (b)  out-of-phase,  in  which  the  MDI 
canister  is  actuated  at  the  start  of  exhalation  and  some  portion  of  the  drug  plume  may  be  retained 
until  the  following  inhalation.  RESULTS:  For  all  4  devices  the  respirable  dose  was  significantly  less 
in  the  out-of-phase  case  than  in  the  in-phase  case.  At  the  same  time,  the  devices  varied  widely  in  the 
percentage  of  the  usable  aerosol  plume  that  was  retained  in  the  out-of-phase  case.  The  percentages 
retained  until  the  following  inhalation  (as  compared  with  the  amount  of  drug  delivered  in  the 
in-phase  case)  are  as  follows:  MediSpacer  67%,  ACE  23%,  OptiHaler  9%,  and  AeroChamber  46%. 
CONCLUSIONS:  Timing  greatly  affects  the  amount  of  drug  delivered  by  an  MDI  device,  even  one 
equipped  with  a  valve.  Also,  device  design  has  a  large  influence  on  the  amount  of  drug  delivered  and 
the  percentage  of  the  drug  plume  retained  when  inhalation  is  delayed.  The  variable  flow  rate 
technique  made  this  study  possible,  and  this  technique  may  also  have  applications  in  studying  the 
effects  of  unusual  breathing  patterns.  [Respir  Care  1999;44(12):1474-1485]  A'e}'  words:  aerosol 
delivery,  metered  dose  inhaler,  spacer  device,  in  vitro  testing,  dose  output,  particle  size,  patient  education. 


Background 

For  patient  self-medication,  metered  dose  inhalers 
(MDIs)  have  been  used  since  1956  and  are  convenient  and 


Scott  A  Foss  and  Jean  W  Keppel  PhD  are  affiliated  with  Thayer  Medical 
Corporation  (manufacturer  of  the  MediSpacer),  Tucson,  Arizona. 

Mr  Foss  presented  a  version  of  this  paper  at  the  American  Association  for 
Respiratory  Care  Open  Forum  during  the  43rd  International  Respiratory 
Congress,  December  6-9.  1997.  in  New  Orleans.  Louisiana. 

Correspondence:  Jean  W  Keppel  PhD,  Thayer  Medical  Corporation,  457.'5 
S  Palo  Verde  Road,  Suite  337,  Tucson  AZ  85714-1961.  E-mail: 
connect@thayermed.com. 


durable  devices.'  However,  many  patients  have  found  it 
difficult  to  synchronize  inhalation  with  actuation  of  the 
MDI  canister,  even  with  some  training.  A  large  body  of 
literature  addresses  this  timing  difficulty;  only  a  few  ref- 
erences are  listed  here.- ''  Without  an  auxiliary  device,  if 
the  MDI  canister  is  actuated  after  inhalation  is  completed, 
the  effect  of  the  drug  is  reduced  to  almost  nil.^ 

Any  spacer  or  chamber  will  reduce  oropharyngeal  depo- 
sition of  the  MDI  drug  and  thus  reduce  the  adverse  effects  of 
oral  deposition.^  Valved  chambers  are  also  designed  to  re- 
duce the  synchronization  problem,  by  retaining  a  portion  of 
the  usable  drug  plume  if  the  patient's  timing  is  faulty.'*'^ 

The  purposes  of  the  present  study  were  ( 1 )  to  measure 
how  much  of  the  respirable  dose  is  retained  when  a  valved 


147-^ 


Respiratory  Care  •  December  1999  Vol  44  No  12 


In  Vitro  Testing  of  MDI  Spacers 


USP  Throat  Model 


Fig.  1.  Schematic  diagram  of  experimental  setup  for  the  VFR 
method.  Note  that  the  traditional  constant-flow  method  would  not 
include  the  T-piece,  the  Y-piece,  the  breathing  machine,  or  the 
pressurized  air  source.  Tee  =  T-piece.  Wye  =  Y-piece.  MDI  = 
metered-dose  inhaler.  USP  =  United  States  Pharmacopeia. 

MDI  chamber  is  used  with  incorrect  timing,  (2)  to  com- 
pare the  usable  dose  retention  among  several  chamber  de- 
signs, and  (3)  to  find  out  whether  any  portion  of  the  re- 
spirable  dose  is  retained  by  an  unvalved  spacer  when  timing 
is  faulty.  To  achieve  these  purposes  we  needed  to  develop  a 
new  laboratory  technique.  Therefore,  it  became  one  of  our 
major  purposes  also  to  present  this  new  technique  as  an  al- 
ternative to  some  of  the  laboratory  methods  used  in  the  past. 

The  most  relevant  dosage  measurement  is  not  the  total 
dose  contained  in  all  aerosol  particle  sizes,  but  rather  the 
dose  contained  in  just  the  1-5  /xm  range,  which  is  more 
likely  to  be  deposited  in  the  small  airways  of  the  lungs.'"" 
In  fact,  the  dose  output  in  the  1-5  /j,m  range  is  sometimes 
referred  to  as  the  respirable  dose."'- 

To  measure  the  respirable  dose,  one  must  measure  the 
amount  of  active  ingredient  as  a  function  of  particle  size. 
Cascade  impaction  is  not  the  only  method  for  measuring 
particle  sizes,  but  it  is  among  the  most  reliable  and  most 
commonly  used.'-*  One  drawback  of  a  cascade  impactor 
has  been  that  the  particle  size  distribution  must  be  mea- 
sured with  a  constant  airflow,  which  is  not  representative 
of  the  cycle  of  a  patient's  breathing.  Moreover,  the  effect 
of  varying  the  timing  of  actuation  relative  to  inhalation 
cannot  be  evaluated  if  the  measurement  technique  demands 
a  constant  flow. 

Most  cascade  impaction  studies  of  respirable  dose  have 
been  confined  to  the  intake  rate  required  for  proper  oper- 
ation of  the  impactor,  such  as  the  28.3  L/min  rate  used  by 
Ahrens  et  al.''*  Some  of  the  drug  delivery  devices  they 
tested  had  no  holding  chamber  and  had  to  be  attached  to 
the  intake  port  before  the  drug  canister  was  actuated.  For 
others  having  a  valved  chamber  to  hold  the  drug  plume, 
the  device  was  attached  to  the  intake  port  one  second  after 
the  canister  was  actuated.  This  testing  method  is  not  ideal. 


for  two  reasons:  the  two  styles  of  delivery  device  were  not 
tested  under  comparable  conditions,  and  in  neither  case 
could  the  drug  plume  develop  and  be  inhaled  as  it  would 
in  actual  usage. 

To  circumvent  these  problems,  we  developed  a  new 
variable  flow  rate  laboratory  technique  that  measures  par- 
ticle size  distribution  while  mimicking  the  sinusoidal 
breathing  cycle  of  a  patient,  and  that  can  be  used  reliably 
for  all  types  of  hand-held  aerosol  drug  dispensers. 

Methods 

Variable  Flow  Rate  Technique 

In  the  variable  flow  rate  (VFR)  technique,  a  breathing 
machine  regulates  the  flow  of  aerosol  particles  into  a  throat 
model,  yet  at  the  same  time  the  particle  sizes  are  measured 
by  an  8-stage  Andersen  cascade  impactor  at  the  (constant) 
standard  flow  of  28.3  L/min.i'-'f' 

Figure  1  shows  a  diagram  of  the  experimental  setup. 
The  MDI  drug  delivery  device  is  attached  to  the  input  of 
an  aluminum  United  States  Pharmacopeia  throat  model. 
The  output  of  the  throat  model  is  attached  by  a  small 
adapter  to  a  T-piece.  One  branch  of  the  T-piece  feeds  into 
the  cascade  impactor,  whose  airflow  is  kept  at  a  constant 
28.3  L/min  by  means  of  a  flow-regulated  vacuum  pump. 
The  other  branch  of  the  T-piece  goes  to  a  Y-piece  that  has 
a  Harvard  breathing  machine  on  one  branch  and  a  pres- 
surized air  source  on  the  other  branch.  The  pressurized  air 
source  is  adjusted  so  that  the  measured  net  airflow  through 
the  throat  model  is  zero  before  the  breathing  machine  is 
turned  on. 

The  traditional  constant-flow  setup  would  consist  only 
of  the  drug  delivery  device,  the  throat  model,  the  cascade 
impactor,  and  the  vacuum  pump.  In  the  VFR  setup  the 
path  of  the  aerosol  is  changed  only  by  the  addition  of  the 
T-piece  and  a  barrel  adapter;  in  Figure  1  the  barrel  adapter 
is  drawn  (only  for  clarity)  as  a  tube  between  the  T-piece 
and  the  throat  model.  Comparisons  between  results  from 
the  traditional  method  and  the  VFR  method''^'^  show  that 
particle  size  distributions  and  throat-model  depositions  are 
unaffected  by  the  change  in  method.  Dose  output  to  the 
cascade  impactor  is  affected  in  some  cases,  because  the 
introduction  of  sinusoidal  flow  through  the  device  changes 
the  dynamics  of  the  aerosol  flow.  For  the  purposes  of  the 
present  study,  the  VFR  method  (or  one  like  it)  must  be 
used,  because  there  is  no  way  to  study  timing  issues  if  the 
flow  through  the  device  is  constant. 

Method  of  Operation 

The  VFR  technique  consists  of  the  following  steps: 
1.  The  vacuum  pump  is  turned  on  to  produce  the  con- 
stant flow  of  28.3  L/min  through  the  cascade  impactor. 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1415 


In  Vitro  Testing  of  MDI  Spacers 


2.  The  pressurized  air  source  is  turned  on  and  adjusted 
so  that  the  measured  airflow  through  the  throat  model  and 
MDI  device  is  zero  (with  the  breathing  machine  off)-  This 
means  that  the  entire  airflow  in  the  system  is  from  the  air 
source  through  the  cascade  impactor,  bypassing  the  throat 
model  and  MDI  device,  before  the  breathing  machine  is 
turned  on.  During  this  setup  step,  a  pair  of  flow  meters  is 
used  to  measure  the  net  airflow  into  or  out  of  the  throat 
model,  to  assure  that  it  is  zero,  and  then  the  flow  meters 
are  removed  from  the  circuit. 

3.  The  breathing  machine  is  turned  on,  causing  a  sinu- 
soidal airflow  through  the  throat  model  and  MDI  device. 
In  this  set  of  tests  the  breathing  machine  was  set  at  5 
breaths  per  minute,  with  an  inspiratory-time:expiratory- 
time  ratio  of  1/1.  Tidal  volume  (Vj)  was  750  mL  and  peak 
inspiratory  (and  expiratory)  flow  was  approximately  12 
L/min. 

4.  At  a  known  point  in  the  breath  cycle,  the  MDI  can- 
ister is  actuated  and  the  aerosol  plume  forms  in  the  MDI 
device. 

5.  The  aerosol  plume  is  drawn  through  the  throat  model 
by  the  breathing-machine  inspiration  (which  peaks  at  ap- 
proximately 12  L/min  here);  once  the  aerosol  passes  the 
T-piece  it  is  drawn  into  the  cascade  impactor  by  the  vac- 
uum pump. 

6.  The  particles  in  the  inhaled  aerosol  cloud  are  col- 
lected and  sorted  by  aerodynamic  size  as  they  pass  through 
the  cascade  impactor  at  a  flow  of  28.3  L/min. 

7.  During  exhalation,  the  breathing  machine  causes  a 
flow  of  air  out  through  the  throat  model  and  MDI  device, 
peaking  at  approximately  12  L/min  here. 

Discussion  of  Operation 

A  flow  meter  inserted  temporarily  between  the  T-piece 
and  the  throat  model  showed  that  the  flow  was  sinusoidal, 
peaking  (in  this  setup)  at  1 1  ±  1  L/min  for  both  inhalation 
and  exhalation.  This  verified  that  the  airflow  through  the 
throat  model  and  MDI  device  is  regulated  entirely  by  the 
breathing  machine. 

At  the  same  time,  the  breathing  machine  has  no  effect 
on  the  constant  flow  through  the  cascade  impactor.  If  a 
flow  meter  is  inserted  just  before  the  cascade  impactor,  it 
shows  no  cyclic  flow  variation  when  the  breathing  ma- 
chine is  turned  on.  The  vacuum  pump,  which  is  flow- 
regulated,  draws  a  steady  28.3  L/min  through  the  impactor 
under  all  conditions.  Before  the  breathing  machine  is  turned 
on,  the  entire  28.3  L/min  comes  from  the  pressurized  air 
source.  When  the  breathing  machine  inhales,  the  28.3  L/min 
is  a  combination  of  flows  from  the  air  source  and  from  the 
throat  model/MDI  device.  When  the  breathing  machine 
exhales,  the  28.3  L/min  is  a  combination  of  flows  from  the 
air  source  and  the  breathing  machine,  with  the  excess  flow- 
ing out  through  the  throat  model/MDI  device. 


INHALING 


'    Throat      ^ 

Model       I 

^  *  1 


2  Umin  — > 


EXHALING 

'f   MDI  Device  J 


Fig.  2.  Flow  rates  in  the  VFR  setup  used  in  tlnis  study,  at  peal<  of 
inhalation  ("INHALING")  and  at  peak  of  exhalation  ("EXHALING"). 
The  widths  of  the  air  pathways  have  been  drawn  to  be  propor- 
tional to  the  flow  rates  (lymin)  through  the  vai  ious  sections  of  the 
test  circuit,  at  these  two  points  of  the  breathing  cycle.  During 
inhalation,  there  is  a  splitting  of  the  airflow  at  the  Y-piece  and  an 
addition  of  two  flows  at  the  T-piece.  During  exhalation,  there  is  an 
addition  of  two  flows  at  the  Y-piece  and  a  splitting  of  the  airflow  at 
the  T-piece  (see  text).  Tee  =  T-piece.  Wye  =  Y-piece.  MDI  = 
metered-dose  inhaler. 


Figure  2  illustrates  the  flow  rates  in  the  setup  used  for 
this  study.  In  the  figure,  the  widths  of  the  air  pathways  are 
proportional  to  the  flow  rates  at  the  peak  of  inhalation  and 
at  the  peak  of  exhalation,  as  labeled.  Of  course,  during  the 
full  breathing  cycle  the  airflow  through  the  MDI  device 
will  vary  between  zero  and  the  peak  values  shown. 

At  the  peak  of  inhalation  (see  the  upper  part  of  Fig.  2, 
"Inhaling")  the  breathing  machine  extracts  12  L/min  from 
the  28.3  L/min  flow  supplied  by  the  air  source,  leaving 
16.3  L/min  to  flow  toward  the  T-piece.  At  the  T-piece,  the 
vacuum  pump  demands  an  additional  1 2  L/min  to  make  up 
the  flow  of  28.3  L/min  to  the  cascade  impactor.  It  draws 
the  additional  12  L/min  from  the  ambient  air,  by  way  of 
the  throat  model  and  MDI  device. 

At  the  peak  of  exhalation  (see  the  lower  part  of  Fig.  2, 
"Exhaling")  the  breathing  machine  adds  its  12  L/min  to 


1476 


Respiratory  Care  •  December  1999  Vol  44  No  12 


In  Vitro  Testing  of  MDI  Spacers 


the  28.3  L/min  supplied  by  the  air  source,  giving  a  total  of 
40.3  L/min  flowing  toward  the  T-piece.  At  the  T-piece,  the 
vacuum  pump  takes  only  28.3  L/min,  leaving  the  remain- 
ing 12  L/min  to  flow  out  into  ambient  air  by  way  of  the 
throat  model  and  MDI  device. 

With  this  arrangement  the  breathing  machine  sets  up  a 
regular  and  very  predictable  sinusoidal  airflow  through  the 
throat  model  and  MDI  device:  in  from  the  MDI  device 
during  inhalation  and  out  through  the  MDI  device  during 
exhalation. 

The  circuit  section  between  the  Y-piece  and  the  T-piece 
also  deserves  particular  attention.  As  the  breathing  ma- 
chine inhales  and  exhales,  its  sinusoidal  airflow  modulates 
the  base  flow  of  28.3  L/min  from  the  pressurized  air  source 
to  the  cascade  impactor.  If  the  breathing  machine  were  to 
have  a  peak  inhalation  flow  of  28.3  L/min,  then  the  flow 
through  this  section  would  be  exactly  zero  at  the  peak  of 
inspiration.  However,  if  the  breathing  machine  had  a  peak 
inhalation  flow  greater  than  the  impactor  flow  of  28.3 
L/min,  it  would  set  up  an  undesirable  net  rightward  flow 
from  the  T-piece  toward  the  Y-piece,  robbing  the  cascade 
impactor  of  some  of  the  MDI  aerosol  particles  it  should 
receive. 

Thus,  for  the  VFR  technique  there  is  one  limitation  on 
the  breathing  machine  flow,  namely,  the  inhalation  flow 
must  never  exceed  the  impactor  flow.  This  condition  was 
easily  satisfied  in  the  current  study,  given  the  peak  inspira- 
tory flow  of  approximately  12  L/min.  Under  proper  oper- 
ation, all  of  the  available  drug  plume  is  carried  directly 
into  the  cascade  impactor,  because  the  net  flow  between 
the  Y-piece  and  the  T-piece  is  always  toward  the  T-piece. 
During  validation  of  the  technique.'''  a  filter  placed  be- 
tween the  Y-piece  and  the  T-piece  collected  no  drug. 

As  long  as  this  requirement  is  satisfied,  the  setup  mim- 
ics actual  inhalation  of  an  MDI  aerosol  while  the  particle 
size  distribution  is  measured  at  a  standard  constant  flow. 
This  allows  simultaneous  measurement  of  (1)  dose  output 
as  a  function  of  particle  size  (via  the  cascade  impactor),  (2) 
throat-model  deposition  (via  rinsings  from  the  throat  mod- 
el), and  (3)  deposition  of  drug  inside  the  spacer  or  chamber 
(via  rinsings  from  the  device)  in  a  realistic  "breathing" 
environment. 

Possible  Variations  of  Breathing  Pattern 

The  VFR  technique  is  not  restricted  to  the  set  of  param- 
eters we  chose  for  the  breathing  pattern  (Vj  750  mL.  5 
breaths/min,  peak  inspiratory  flow  12  L/min).  The  setup 
can  be  adjusted  to  mimic  various  breathing  patterns.  For 
example,  the  Vj  could  be  made  smaller  to  simulate  infant 
or  pediatric  breathing,  or  larger  to  simulate  very  deep  adult 
breaths.  To  accommodate  larger  volumes  or  faster  breath- 
ing rates  (and  therefore  higher  peak  inspiratory  flow  rates) 
the  single  cascade  impactor  could  be  replaced  by  two  im- 


pactors  in  parallel.  In  this  case  the  flow  would  have  to  be 
split  into  two  equal  branches  below  the  T-piece,  each  im- 
pactor receiving  one  branch.  Of  course,  the  pressurized  air 
source  would  then  need  to  be  .set  at  56.6  L/min  (2  X  28.3 
L/min)  to  match  the  flow  through  the  two  impactors.  In 
this  example,  peak  inspiratory  flow  rates  up  to  56.6  L/min 
would  be  allowed. 

We  chose  our  particular  breathing  pattern  for  three  prac- 
tical reasons.  First,  it  guarantees  a  peak  inspiratory  flow 
below  the  maximum  of  28.3  L/min  allowed  in  the  single- 
impactor  setup.  Second,  the  breathing  volume  of  750  mL 
is  realistic  for  an  adult  taking  a  moderately  deep  breath 
(the  typical  Vy  for  healthy  adults  ranges  from  about  400 
mL  to  about  600  mL).'^  Third,  a  breathing  volume  of  750 
mL  is  certain  to  draw  all  of  the  aerosol  out  of  the  MDI 
device  and  down  to  the  T-piece  in  a  single  inhalation.  As 
discussed  below,  the  volumes  of  the  spacer  and  chambers 
we  tested  ranged  from  about  55  mL  to  160  mL.  The  dead 
space  from  the  mouthpiece  of  the  MDI  device  down  to  the 
T-piece  (that  is,  the  volume  of  the  throat  model  plus  the 
adapter  from  the  throat  model  to  the  T-piece)  amounted  to 
an  additional  76  mL.  Thus  the  device  plus  dead  space 
volumes  add  up  to  131-236  mL,  or  less  than  a  third  of 
each  inhaled  volume. 

A  disadvantage  of  this  breathing  pattern  is  the  relatively 
low  peak  inspiratory  flow  of  12  L/min.  The  American 
Association  for  Respiratory  Care  recommends  a  peak  in- 
spiratory flow  of  <  30-45  L/min  for  a  patient  using  an 
MDI.'"  A  peak  flow  of  12  L/min  would  satisfy  this  rec- 
ommendation but  may  be  substantially  lower  than  the  typ- 
ical flow  seen  clinically  in  adults. 

Study  Design 

We  tested  4  brands  of  MDI  device  in  the  VFR  circuit: 
the  Airlife  Hand-Held  MediSpacer,*  the  Aerosol  Cloud 
Enhancer  (ACE),  the  OptiHaler,  and  the  AeroChamber,  all 
of  which  are  illustrated  schematically  in  Figure  3.  The 
MediSpacer,  ACE,  and  AeroChamber  are  holding  cham- 
bers with  one-way  inhalation  valves  that  close  upon  ex- 
halation. The  OptiHaler  is  a  spacer  with  no  valves.  The  3 
holding  chambers  are  also  significantly  larger  than  the 
OptiHaler,  having  volumes  of  approximately  140-160  mL, 
compared  with  OptiHaler' s  approximately  55  mL.  Three 
of  the  devices  (MediSpacer,  ACE,  OptiHaler)  have  an  in- 
tegral nozzle  that  directs  the  aerosol  plume  initially  away 
from  the  patient's  mouth  before  inhalation,  toward  the 
right  in  Figure  3.  The  AeroChamber  has  an  elastomeric 
adapter  to  accommodate  the  drug  manufacturer's  nozzle/ 


*Suppliers  of  commercial  products  are  identified  in  the  Product  Sources 
section  at  the  end  of  the  text. 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1477 


In  Vitro  Testing  of  MDI  Spacers 


Ona-Way  Exhalation  Valve 


Mouthpiece 


MDI  Canister 


LJ 


One-way  Inhalation  Valve 


MediSpacer 


One-way  Inhalation  Valve 


Mouthpiece 


Mouthpiece 


MDI  Canister 


MDI  Canister 


M 


One-Way  Inhalation  Valve 


OptiHaler 


\v 


c 


Mouthpiece 


y         AeroChamber 


Fig.  3.  Schematic  diagrams  of  the  4  MDI  devices  tested  in  this  study.  Drawings  are  to  scale  with  respect  to  each  other.  Locations  of  all 
valves  are  indicated.  MDI  =  metered-dose  inhaler. 


mouthpiece,  and  the  aerosol  plume  is  directed  initially 
toward  the  patient's  mouth. 

Devices  were  tested  in  a  cyclic  sequence  (A-B-C-D, 
A-B-C-D,  etc),  so  that  no  bias  was  introduced  by  any 
minor  changes  in  the  drug  canister  or  the  test  environment. 
For  each  trial,  the  device  was  placed  in  the  VFR  circuit  as 
shown  in  Figure  1,  and  Ventolin  (albuterol,  90  ;ag  unit 
dose)  was  dispensed  through  the  device  into  the  VFR  circuit. 

We  tested  each  device  to  simulate  two  conditions:  (a) 
In-phase:  the  ideal  condition  in  which  the  patient  actuates 
the  Ventolin  canister  at  the  start  of  inhalation.  In  this  con- 
dition the  canister  was  actuated  just  as  the  breathing  ma- 
chine started  the  inspiratory  part  of  its  cycle,  (b)  Out-of- 
phase:  the  undesirable  condition  in  which  the  patient 
actuates  the  Ventolin  canister  at  the  start  of  exhalation.  In 
this  condition  the  canister  was  actuated  just  as  the  breath- 
ing machine  started  the  expiratory  part  of  its  cycle,  so  the 
drug  plume  was  not  "inhaled"  until  the  breathing  machine 
came  around  to  the  next  inhalation,  6  seconds  later. 

Our  laboratory  setup  included  a  pneumatic  actuator,  elec- 
tronically tied  to  the  breathing  machine,  which  automati- 
cally depressed  the  MDI  canister  at  the  desired  point  in  the 
breathing  cycle. 

For  each  brand  of  device  and  each  phase  condition  (in- 
phase  and  out-of-phase),  5  trials  were  averaged.  Each  trial 
was  done  with  a  different  sample  device  of  the  brand  being 


tested,  so  that  5  samples  of  each  brand  were  used.  Fifty 
doses  were  required  for  each  trial,  to  collect  a  properly- 
measurable  amount  of  albuterol  on  each  of  the  8  plates  of 
the  cascade  impactor. 


Measurement  of  Drug 

Each  plate  of  the  cascade  impactor  was  rinsed  with  25 
mL  of  a  phosphate  buffer  (aqueous  solution  of  0.4M 
KH2PO4  -I-  0.2M  HCl).  Ultraviolet  spectrophotometric 
analysis  at  275  nm  yielded  the  number  of  micrograms  of 
albuterol  per  dose  in  each  of  the  particle  size  ranges  sorted 
by  the  cascade  impactor. 

A  similar  procedure  was  used  to  measure  the  amount  of 
each  dose  trapped  in  the  throat  model  and  in  the  device, 
except  that  the  throat  model  and  device  were  each  rinsed 
with  50  mL  of  the  phosphate  buffer. 


Data  Analysis 

From  each  trial  we  derived  several  numbers,  normalized 
to  a  single-breath  cycle  through  the  device: 

•  Micrograms/dose  of  albuterol  collected  on  each  of  the 
8  plates  of  the  cascade  impactor. 


1478 


Respiratory  Care  •  December  1999  Vol  44  No  12 


In  Vitro  Testing  of  MDI  Spacers 


25 


20 


15 


2  10 


S 
.2     5 


b 

ACE 

S         T 

s 

1 

M 

B+1    A-^ 

0  12  3  4  5  6  7 

Plate  Number,  cascade  impactor 


2  3  4  5 

Plate  Number,  cascade  Impactor 


12  3  4  5  6 

Plate  Number,  cascade  Impactor 


0  12  3  4  5  6  7 

Plate  Number,  cascade  Impactor 


Fig.  4.  In-phase  and  out-of-phase  dose  output  collected  on  each  of  the  8  plates  of  the  cascade  impactor  in  each  breath  cycle.  Error  bars 
are  1  standard  deviation.  Cascade  impactor  plate  numbers  (along  abscissa)  correspond  to  the  following  particle-size  ranges:  0  10.0-9.0 
/xm,  1  9.0-5.8  (xm,  2  5.8-4.7  /xm,  3  4.7-3.3  ixm,  4  3.3-2.1  ixm,  5  2.1-1.1  /xm,  6  1.1-0.65  ^m,  7  0.65-0.43  /^tm.  Note  that  the  sum  of  the 
albuterol  collected  on  Plates  3,  4,  and  5  is  equivalent  to  the  respirable  dose.  The  label  claim  for  Ventolin  is  90  /j.g  per  unit  dose. 

Table  1 .      Respirable  Dose  Delivered  to  the  Cascade  Impactor  in  Each  Breath  Cycle* 


MediSpacer 


ACE 


OptiHaler 


AeroChamber 


In-phase  (^g) 

36  ±  3 

26  ±6 

15  ±4 

24  ±  2 

Out-of-phase  (jxg) 

24  ±6 

6±4 

1.3  ±0.3 

11  ±  3 

p  value 

0.005 

0.0005 

0.002 

0.0002 

Ratio  of  in-phase  to  out-of-phasef 

1:0.67 

1:0.23 

1:0.09 

1:0.46 

♦Expressed  in  /ig  of  albuterol  per  dose:  mean  and  standard  deviation  of  5  trials  in  each  case.  The  label  claim  for  Ventolin  is  90  /ig  per  unit  dose.  The  p  values  arc  from  /  tests  comparing  the  in- 
phase  dose  and  out-of-phase  dose  for  each  device;  differences  are  considered  statistically  significant  if  p  <  0.05. 
tRatio  of  in-phase  respirable  dose  to  out-of-phase  respirable  dose. 
ACE  =  Aerosol  Cloud  Enhancer. 


•  Respirable  dose  (the  sum  of  the  micrograms/dose  of 
albuterol  collected  on  the  3  cascade  impactor  plates  cov- 
ering the  respirable  range  of  particle  sizes  [1.1  to  4.7  /Am]). 

•  The  sum  of  the  micrograms/dose  of  albuterol  collected 
on  all  8  plates  of  the  cascade  impactor. 

•  Micrograms/dose  of  albuterol  collected  in  the  throat 
model. 


•  Micrograms/dose  of  albuterol  trapped  inside  the  spacer 
or  chamber. 

•  Total  micrograms/dose  of  albuterol  collected  through- 
out the  system  (all  8  plates  of  the  cascade  impactor  plus 
the  throat  model  plus  the  MDI  device). 

For  each  brand  of  device  and  each  phase  condition,  we 
calculated  the  mean  and  standard  deviation  of  the  latter 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1479 


Table  2.      Amount  of  Drug/Dose 


In  Vitro  Testing  of  MDI  Spacers 


MediSpacer 


ACE 


OptiHaler 


AeroChamber 


Cascade  impactor* 

In-phase  (;ag)  42  ±  4  31  ±  7  18  ±5  29  ±  3 

Out-of-phase  (/xg)  28  ±  6  8  ±  5  2.6  ±  0.3  14  ±  4 

p  value  0.003  0.0005  0.002  0.0001 

Throat  modelt 

In-phase  (/xg)  0.8  ±  0.1  0.8  ±  0.2                            '        0.8  ±  0.4  1.4  ±0.6 

Out-of-phase  (ng)  1.1  ±0.4  0.8  ±  0.6  0.8  ±  O.I  0.8  ±  0.2 

p  value  0.2  0.8  1.0  0.07 

Inside  devicet 

In-phase  ((xg)  51  ±  8  51  ±  2  68  ±  16  51  ±  7 

Out-of-phase  (fxg)  50  ±  1 1  47  ±  2  84  ±  8  63  ±  15 

p  value  0.8  0.02  0.1  0.1 

Total  collected§ 

In-phase  (fxg)  94  ±  9  83  ±  7  87  ±  19  81  ±9 

Out-of-pha.se  (^g)  79  ±  15  56  ±  7  87  ±  8         .  78  ±  16 

p  value  0.1  0.0003  I.O  0.7 

*Collecled  in  all  8  stages  of  the  cascade  impactor. 

tTrapped  in  the  throat  model. 

^Trapped  inside  the  device. 

§Total  collected  (all  8  plates  of  the  ca.scade  impactor  plus  the  throat  model  plus  the  metered-dose  inhaler  device)  for  each  device,  expressed  in  ^g  of  albuterol  per  dose:  mean  and  standard  deviation 

of  5  trials  in  each  case. 

Data  from  inside  device  and  total  collected  are  graphed  in  Figure  5.  The  label  claim  for  Ventolin  is  90  iig  per  unit  dose.  The  p  values  are  from  I  tests  comparing  the  in-phase  dose  and  out-of-phase 

dose  for  each  device:  differences  are  considered  statistically  significant  if  p  <  O.O.'i. 

ACE  -  Aerosol  Cloud  Enhancer. 


numbers  for  the  5  trials.  These  were  not  paired  observa- 
tions. The  in-phase  and  out-of-phase  averages  for  each 
individual  brand  were  compared  by  means  of  two-tailed  / 
tests  with  unequal  variances;  differences  were  considered 
statistically  significant  if  p  was  <  0.05. 


Results 

Figure  4  shows  the  in-phase  and  out-of-phase  dose  out- 
put collected  on  each  of  the  8  plates  of  the  cascade  im- 
pactor, for  MediSpacer  (Fig.  4a),  ACE  (Fig.  4b),  Opti- 
Haler (Fig.  4c),  and  AeroChamber  (Fig.  4d).  The  respirable 
dose  was  taken  to  be  the  sum  of  the  micrograms  of  al- 
buterol collected,  during  a  single  breath  cycle,  on  Plates 
3,  4,  and  5,  covering  a  particle  size  range  from  1 . 1  /itm  to 
4.7  /Ltm. 

For  all  4  brands  of  device,  the  respirable  dose  delivered 
to  the  cascade  impactor  was  significantly  less  in  the  out- 
of-phase  case  than  in  the  in-phase  case.  These  results  are 
shown  in  Table  1 ,  along  with  the  p  values  for  the  t  tests 
comparing  the  two  phase  conditions  for  each  device.  If  the 
MDI  canister  is  actuated  at  the  start  of  exhalation,  the 
MediSpacer  delivers  about  two  thirds  of  the  dose  it  would 
deliver  if  the  MDI  canister  were  actuated  properly  at  the 
start  of  inhalation.  Similarly,  the  AeroChamber  delivers 


about  half  of  its  best  dose,  the  ACE  about  one  quarter,  and 
the  OptiHaler  about  one  tenth,  when  the  actuation  is  com- 
pletely mistimed.  As  shown  in  the  final  row  of  Table  1,  the 
out-of-phase  respirable  dose  is  as  follows:  MediSpacer 
67%,  ACE  23%,  OptiHaler  9%,  and  AeroChamber  46%. 

What  happens  to  the  albuterol  that  does  not  make  it  to 
the  cascade  impactor  in  the  out-of-phase  case?  Aside  from 
the  cascade  impactor,  there  are  two  other  locations  in  the 
VFR  circuit  where  a  significant  part  of  the  drug  plume 
could  accumulate:  in  the  throat  model  and  in  the  device 
itself.  The  drug  deposition  in  these  two  locations,  along 
with  the  sum  total  of  albuterol  collected  (all  8  plates  of  the 
cascade  impactor  plus  the  throat  model  plus  the  MDI  de- 
vice) will  tell  us  where  the  out-of-phase  drug  loss  occurs. 

For  each  brand  of  device  and  each  phase  condition. 
Table  2  lists  the  average  amount  of  albuterol  per  dose 
collected  in  all  8  stages  of  the  cascade  impactor,  trapped  in 
the  throat  model,  trapped  inside  the  device,  and  collected 
throughout  the  total  system,  along  with  the  p  values  for  t 
tests  comparing  the  two  phase  conditions  for  each  device. 
In-phase,  for  all  4  devices,  the  total  collected  was  within  1 
standard  deviation  of  the  ex-mouthpiece"*  Ventolin  label 
claim  of  90  /xg  per  dose  (the  label  claim  having  a  relative 
standard  deviation  of  <  15%,  ideally"*).  Out-of-phase,  the 
total  was  within  1  standard  deviation  of  the  label  claim  for 
all  devices  except  ACE.  This  situation  is  discussed  in  the 
next  section. 


1480 


Respiratory  Care  •  December  1999  Vol  44  No  12 


In  Vitro  Testing  of  MDI  Spacers 


0) 
V) 

o 

TJ 
0) 

a 


3 

n 
re 


o 


110 
100 
90 
80 
70 
60 
50 
40 
30 
20 
10 
0 


a 

- 

b 

c 

r 

d 

Label  Claim 

T 

T 

T 

J 

1 

T 

- 

I      1 

r 

1 

r- 

^ 

- 

II 

-^ 

— 

— 

1 

- 

— 

Trapped        Total 
Inside        Collected 
Device 

MediSpacer 

Trapped        Total 
Inside       Collected 
Device 

ACE 

Trapped        Total 
Inside        Collected 
Device 

OptiHaler 

Trapped        Total 
Inside         Collected 
Device 

AeroChamber 

re 
a. 


D 


0) 

in 

re 

Q. 


Fig.  5.  In-phase  and  out-of-phase  drug  collection,  per  actuation,  trapped  inside  the  device  and  collected  throughout  the  system.  This  is  a 
graph  of  the  data  from  the  inside  device  and  total  collected  sections  of  Table  2.  The  amount  trapped  inside  the  device  would  not  reach  the 
patient  in  actual  use.  Error  bars  are  1  standard  deviation.  Note  that  the  total  amount  of  albuterol  collected  per  actuation  is  within  1  standard 
deviation  of  the  label  claim  for  Ventolin  in  all  cases  except  for  ACE  in  the  out-of-phase  case  (see  text). 


Discussion 
Accounting  for  "Lost"  Drug 

As  Table  2  shows,  throat-model  deposition  cannot  ac- 
count for  the  out-of-phase  decrease  in  respirable  dose.  The 
t  tests  gave  p  >  0.05  in  the  comparison  of  throat-model 
rinsings  for  the  in-phase  and  out-of-phase  cases  for  all  4 
brands.  Throat  deposition  remains  small,  independent  of 
the  timing  of  actuation.  Therefore  the  last  two  categories 
in  Table  2,  the  amount  trapped  inside  the  device  and  the 
total  collected,  are  the  only  possibilities  remaining  to  ac- 
count for  the  dose-output  differences  between  the  two  phase 
conditions.  Figure  5  shows  a  comparison  of  the  in-phase 
and  out-of-phase  amounts  of  albuterol  per  dose  collected 
inside  the  device  and  in  total,  for  each  of  the  4  brands. 

For  MediSpacer  and  ACE  (Figs.  5a  and  5b),  the  amount 
of  albuterol  trapped  inside  the  device  does  not  depend 


strongly  on  the  time  of  actuation,  but  the  total  amount  of 
drug  collected  decreases  in  the  out-of-phase  case.  Some 
drug  may  have  disappeared  from  the  system.  This  suggests 
that  the  decrease  in  respirable  dose  could  be  due  to  leakage 
of  drug  out  of  the  chamber  for  MediSpacer  and  ACE. 

For  OptiHaler  and  AeroChamber  (Figs.  5c  and  5d),  the 
situation  seems  to  be  reversed.  The  amount  of  albuterol 
trapped  inside  the  device  appears  to  increase  somewhat  in 
the  out-of-phase  case,  while  the  total  amount  of  drug  col- 
lected stays  the  same.  For  OptiHaler  and  AeroChamber, 
then,  the  decrease  in  respirable  dose  may  be  due  to  in- 
creased deposition  of  drug  on  the  inner  walls  of  the  device. 

These  suggestions  about  what  happens  to  the  "lost"  drug 
require  verification,  because  some  of  the  error  bars  in 
Figure  5  are  large.  For  example,  the  amount  trapped  inside 
the  OptiHaler  is  68  ±  16  ju,g/dose  in-phase  and  84  ±  8 
jixg/dose  out-of-phase,  and  the  difference  in  these  values  is 
not  statistically  significant  (p  =  0.1).  This  makes  it  im- 


Respiratory  Care  •  December  1999  Vol  44  No  12 


148: 


In  Vitro  Testing  of  MDI  Spacers 


possible  to  determine  unequivocally  the  fate  of  the  albu- 
terol that  does  not  make  it  to  the  cascade  impactor. 

Assuming  that  our  suggestions  can  be  verified  in  future 
testing,  we  can  speculate  as  to  the  explanations.  Our  in- 
tention here  is  to  discuss  design  differences  that  could  lead 
to  different  behavior  in  the  4  devices. 

Devices  for  which  the  "lost"  drug  disappears  from  the 
system  in  the  out-of-phase  case.  In  the  MediSpacer  the 
one-way  inhalation  valve  is  not  located  in  the  mouthpiece. 
Even  so,  exhaled  breath  cannot  enter  the  chamber,  because 
the  one-way  inhalation  valve  is  closed  during  exhalation, 
forming  an  air  pillow  inside  the  chamber.  Most  of  the 
exhaled  air  exits  through  the  one-way  exhalation  valve  in 
the  mouthpiece,  but  as  it  goes  out  it  may  entrain  some  of 
the  aerosol-laden  air  from  inside  the  chamber.  The  ACE 
does  have  a  one-way  inhalation  valve  in  the  mouthpiece, 
but  there  is  nothing  to  prevent  some  portion  of  the  aerosol 
plume  from  exiting  out  through  the  unvalved  end.  In  ad- 
dition, if  the  valve  leaks,  some  of  the  exhaled  air  may  pass 
through  the  chamber  and  carry  drug  particles  out. 

Devices  for  which  the  "lost"  drug  is  trapped  inside  the 
device  in  the  out-of-phase  case.  The  OptiHaler  has  no 
valves,  so  the  exhaled  breath  can  pass  through  the  spacer 
and  out  the  small  air  vents  on  the  other  end.  When  this 
happens,  drug  particles  can  be  blown  against  the  spacer 
walls  and  be  "lost"  by  impaction.  Most  particles  presum- 
ably do  not  escape  from  the  spacer  during  this  maneuver, 
because  to  do  so  they  would  have  to  get  through  very 
small  holes  or  around  hairpin  turns  at  the  end  of  the  spacer. 
The  AeroChamber  has  a  one-way  inhalation  valve  in  the 
mouthpiece  that  prevents  the  exhaled  air  from  entering  the 
chamber.  In  this  device  the  apparent  increase  in  device 
deposition  in  the  out-of-phase  case  could  be  caused  by 
more  than  one  factor.  (1)  When  the  MDI  canister  is  actu- 
ated with  no  airflow  through  the  chamber,  the  aerosol 
plume  does  not  have  the  benefit  of  an  inhalation  to  carry 
it  immediately  out  through  the  one-way  valve.  Instead, 
some  of  the  drug  particles  that  would  have  been  inhaled 
will  impact  direcdy  on  the  inside  of  the  chamber.  (2)  Grav- 
itational settling  would  be  insignificant  for  particles  with 
diameters  less  than  about  5  /^tm,  but  larger  particles  could 
settle  out  in  the  time  it  takes  for  the  exhalation  phase 
(about  6  seconds  in  these  tests).''*  However,  if  this  were  an 
important  mechanism  for  the  AeroChamber,  we  would 
expect  the  particle  size  distribution  to  shift  toward  smaller 
sizes  in  the  out-of-phase  case,  which  is  not  seen.  In  Figure 
4d,  plates  3  through  7  would  hardly  be  affected  by  grav- 
itational sedimentation  over  6  seconds,  yet  for  the.se  plates 
there  is  a  very  clear-cut  difference  between  the  two  phases. 
Therefore  we  conclude  that  sedimentation  is  not  the  pri- 
mary means  by  which  drug  is  "lost"  in  the  AeroChamber 
in  the  out-of-phase  case.  (3)  During  the  6-second  delay 


between  actuation  and  inhalation,  the  drug  plume  is  not 
statically  suspended  inside  the  chamber.  Rather,  turbulent 
motion  persists  within  the  aerosol  cloud  for  the  few  sec- 
onds immediately  following  its  ejection  from  the  canister. 
In  the  out-of-phase  case  the  several  seconds  of  turbulence 
could  add  to  the  inertial  impaction  of  drug  particles  onto 
the  chamber  walls.  Unlike  sedimentation,  this  mechanism 
would  not  sort  by  particle  size  and  therefore  is  a  more 
plausible  explanation  of  the  observations  shown  in  Figure 
4d.  (4)  If  electrostatic  deposition  is  occurring  inside  the 
chamber,  the  6-second  delay  will  increase  the  amount  of 
drug  "lost"  by  this  mechanism. 

Comparison  with  Other  Results 

Although  we  do  not  have  available  any  other  research- 
ers' studies  that  are  exactly  like  this  one,  Mitchell  et  al-" 
have  recently  carried  out  a  study  that  is  closely  related  to 
ours,  and  have  observed  comparable  behavior.  Their  study 
compared  the  total  unit  dose  output  of  two  MDI  delivery 
devices,  with  actuation  at  the  start  of  inhalation  (our  in- 
phase  case)  and  actuation  at  the  start  of  exhalation  (our 
out-of-phase  case).  They  found,  as  we  do,  that  (a)  the  dose 
output  was  highest  when  actuation  was  synchronized  with 
inhalation,  and  (b)  a  valved  holding  chamber  retains  more 
of  the  usable  aerosol  drug  plume  than  does  an  unvalved 
spacer,  in  the  event  of  mistiming. 

The  Mitchell  et  al  study  differed  from  ours  in  some 
respects,  yet  led  to  very  similar  conclusions: 

1 .  They  collected  what  could  be  called  the  "patient  dose" 
by  means  of  a  filter  directly  following  the  mouthpiece  of 
the  device,  whereas  we  collected  the  patient  dose  by  means 
of  the  throat  model  and  all  8  plates  of  the  cascade  impac- 
tor, derived  by  adding  the  throat  model  amount  plus  the 
cascade  impactor  amount  from  our  Table  2.  A  rough  nu- 
merical comparison  shows  the  results  of  the  two  studies  to 
be  similar.  Mitchell  et  al  found  that  the  out-of-phase  dose 
is  60%  of  the  in-phase  dose  for  the  AeroChamber  (a  valved 
holding  chamber),  whereas  we  found  approximately  50% 
for  the  AeroChamber.  For  an  unvalved  spacer,  they  found 
an  out-of-phase  to  in-phase  ratio  of  1 2%  (for  the  Micro- 
Chamber)  whereas  we  found  approximately  16%  (for  the 
OptiHaler).  Both  studies  point  to  the  clear  advantage  in 
using  a  valved  chamber  if  the  patient  does  not  synchronize 
actuation  with  inhalation. 

2.  They  tested  with  Flovent  (fluticasone  propionate,  a 
corticosteroid),  whereas  we  used  Ventolin  (albuterol,  a 
bronchodilator).  Ahrens  et  al''*  and  Rau  et  al-'  caution  that 
MDI  delivery  devices  may  differ  in  their  relative  effi- 
ciency depending  on  the  MDI  drug  being  used.  Nonethe- 
less, the  conclusions  of  our  study  are  very  much  in  agree- 
ment with  those  of  Mitchell  et  al. 


148: 


Respiratory  Care  •  December  1999  Vol  44  No  12 


In  Vitro  Testing  of  MDI  Spacers 


Limitations  of  VFR  Method  and  Comparison  with 
Other  Methods 


The  main  limitation  of  tiie  VFR  technique  is  the  restric- 
tion to  inhalation  flow  rates  less  than  the  flow  required  to 
operate  the  cascade  impactor.  As  noted  above,  the  maxi- 
mum allowable  flow  could  be  doubled  by  using  two  im- 
pactors  in  parallel,  but  this  would  make  the  technique 
considerably  more  cumbersome. 

Two  other  groups  have  recently  published  particle-size 
studies  with  in  vitro  breathing  that  is  not  restricted  in  this 
way.  22-24 

Finlay22-2''  simulated  tidal  breathing  with  a  piston  oper- 
ated by  a  computer-controlled  stepper  motor;  an  electronic 
trigger  opens  a  valve  to  allow  ambient  air  into  the  system 
when"  needed  for  inhalation,  and  closes  the  valve  during 
exhalation.  This  setup  could  be  used  for  phase  studies  like 
ours,  but  the  work  reported  so  far  has  not  been  for  this 
purpose.  Instead,  the  piston  was  cycled  through  5  com- 
plete breaths  per  MDI  actuation  to  simulate  infant  and 
pediatric  breathing.  Presumably,  the  stepper  motor  in  Fin- 
lay's  setup  would  allow  a  variety  of  breathing  profiles,  but 
the  profile  he  has  used  is  a  square  wave, 22  which  is  less 
realistic  than  our  sinusoidal  profile. 

Another  electronic  inhalation  device  has  been  devel- 
oped by  Burnell  et  aP-*  to  test  particle  sizes  and  doses  from 
dry  powder  inhalers.  The  goal  here  was  also  to  do  in  vitro 
testing  under  realistic  breathing  conditions.  The  inhalation 
can  be  preprogrammed  to  follow  any  desired  profile.  This 
device  could  not  be  used  for  an  MDI  phase  study  like  ours, 
however,  because  it  cannot  exhale  through  the  drug  deliv- 
ery device.  It  is  well  suited  for  dry  powder  inhaler  studies, 
in  which  the  ideal  inhalation  rate  is  higher  than  for  MDIs'* 
and  breath-hand  coordination  is  not  as  important  an  issue 
as  with  MDIs. 

The  simplicity  of  the  VFR  technique  is  both  a  disad- 
vantage and  an  advantage.  The  breathing  profile  is  limited 
to  pediatric  flow  rates  or  the  lower  range  of  adult  rates. 
However,  because  the  technique  requires  no  specialized  or 
programmable  equipment,  it  has  the  potential  for  being 
used  widely  and  reproducibly. 

Particle  Size  Distributions 

The  Ventolin  particle  size  distributions  peak  at  Plate  5 
(2.1-1.1  jam)  for  all  4  devices  in  our  study,  in  both  phase 
conditions.  Figure  4  shows  that  the  shape  of  the  overall 
distribution  is  similar  for  all  cases  tested.  The  t  tests  for 
each  of  the  8  plates  of  the  cascade  impactor  show  that  the 
MediSpacer  and  AeroChamber  distributions  are  indepen- 
dent of  phase.  A  meaningful  numerical  comparison  could 
not  be  made  for  the  ACE  and  OptiHaler  because  the  out- 
of-phase  readings  were  too  close  to  the  detection  limit. 


Ventolin  inhalation  aerosol  is  a  microcrystalline  suspen- 
sion of  albuterol  in  liquid  propellants,  with  the  particle  size 
distribution  broadly  specified  (95%  <  10  ^im)  in  the  prod- 
uct information  insert.  Though  the  particle  size  distribu- 
tion may  vary  from  batch  to  batch  of  a  particular  brand  of 
microcrystalline  drug,  our  measurements  suggest  that  it  is 
not  affected  by  time  of  actuation,  size  of  delivery  device, 
presence  or  absence  of  valves  in  the  delivery  device,  or 
location  of  valves  in  the  delivery  device. 

Future  Work  with  the  VFR  Method 

Many  variations  and  refinements  of  this  work  are  pos- 
sible, including: 

•  Actuating  the  MDI  canister  at  different  phases  of  the 
breath  cycle,  such  as  one  or  two  seconds  before  or  after  the 
start  of  inhalation,  to  map  out  the  drug  delivery  efficiency 
as  a  function  of  the  delay. 

•  Taking  measurements  at  a  different  breathing  rate, 
inspiratory-time:expiratory-time  ratio,  Vj,  or  peak  flow,  to 
simulate  a  profile  corresponding  to  a  different  type  of 
patient. 

•  Checking  the  hypotheses  concerning  the  leakage  (or 
lack  thereof)  out  of  the  MDI  devices  in  the  out-of-phase 
case,  possibly  using  low-resistance  filters  placed  at  strate- 
gic locations. 

•  Rinsing  the  T-piece  to  see  if  any  significant  amount  of 
drug  is  trapped  there,  but  the  current  results  suggest  that 
this  could  not  be  a  very  large  factor,  because  we  recovered 
close  to  the  nominal  unit  dose  of  Ventolin  in  almost  all 
cases;  still  it  should  be  measured  directly. 

Conclusions 
Patient  Education 

The  main  inference  to  be  drawn  is  that,  though  device 
design  is  important,  timing  greatly  affects  the  amount  of 
drug  delivered  to  the  lung  by  any  spacer  or  chamber.  We 
found  this  to  be  true  for  all  4  MDI  delivery  devices  we 
tested.  A  patient  who  actuates  the  MDI  canister  upon  ex- 
halation might  receive  between  two  thirds  and  almost  none 
of  the  best  possible  dose,  depending  on  the  device. 

In  our  study,  the  devices  that  are  best  at  retaining  part  of 
the  drug  plume  are  true  holding  chambers;  that  is,  they 
have  a  one-way  inhalation  valve  that  prevents  exhaled  air 
from  mixing  significantly  with  the  drug  plume  in  the  cham- 
ber. They  also  have  a  chamber  volume  of  >  140  mL. 
However,  even  the  best  devices  do  not  deliver  100%  of  the 
drug  plume  if  the  patient  mistimes  actuation  and  inhala- 
tion. Considerations  of  effectiveness  and  cost  may  make  a 
loss  of  a  third  or  more  of  the  dose  unacceptable.  If  a 
patient  loses  half  of  the  expected  dose  because  of  mis- 


Respiratory  Care  •  December  1999  Vol  44  No  12 


148 


In  Vitro  Testing  of  MDI  Spacers 


timing,  the  number  of  puffs  would  have  to  be  doubled  to 
get  the  expected  result. 

In  light  of  this  finding,  we  conclude  that  patient  training 
is  very  important  in  MDI  use,  even  if  a  valved  chamber  is 
provided.  The  "Helpful  Hints'"  included  in  the  AeroCham- 
ber  instruction  leaflet  state  that  "The  one-way  valve  allows 
you  to  inhale  at  your  own  rate  so  that  coordination  of 
inhalation  with  the  actuation  of  the  inhaler  is  not  a  prob- 
lem." We  agree  that  an  MDI  chamber  helps  to  retain  some 
of  the  dose  if  actuation  and  inhalation  are  not  coordinated, 
but  a  significant  portion  of  the  drug  may  be  "lost"  if  the 
patient  is  not  trained  to  actuate  the  canister  at  the  start  of 
inhalation. 

The  1 997  "Practical  Guide  for  the  Diagnosis  and  Man- 
agement of  Asthma"-''  instructs  the  patient,  "If  you  use  a 
holding  chamber,  first  press  down  on  the  inhaler.  Within  5 
seconds,  begin  to  breathe  in  slowly."  We  have  shown  that, 
even  with  a  valved  holding  chamber,  a  significant  portion 
of  the  drug  will  be  "lost"  if  the  patient  actually  waits  4-5 
seconds — particularly  if  the  patient  is  exhaling  into  the 
mouthpiece  during  those  few  seconds.  Ideally  there  should 
be  no  delay  between  canister  actuation  and  the  start  of 
inhalation. 

The  instructions  for  use  that  come  with  the  ACE  cham- 
ber direct  the  patient  to  "Take  a  second  slow,  deep  breath 
from  the  ACE  to  ensure  you've  received  all  the  drug  from 
the  chamber,"  after  the  first  inhalation,  a  10-second  breath- 
hold,  and  exhalation.  Our  study  indicates  that  this  second 
deep  breath  will  not  be  fruitful. 

Although  many  MDI  drugs  are  not  labeled  for  use  by 
children  under  12  years  of  age,  it  is  possible  that  some 
MDIs  are  used  with  a  reservoir  device  by  children  as  young 
as  4  years  of  age.^^  For  such  patients,  where  synchroniza- 
tion of  actuation  and  inhalation  may  be  difficult  to  control, 
there  will  be  particular  benefit  in  choosing  a  valved  hold- 
ing chamber  that  retains  the  majority  of  the  drug  plume  for 
a  few  seconds. 

In  fact,  referring  back  to  the  sources  cited  at  the  begin- 
ning of  this  paper,2  **  we  suggest  that  the  same  statement 
could  be  made  for  many  patients  of  all  ages. 

VFR  Technique 

This  study  would  not  have  been  possible  without  the 
variable  flow  rate  technique,  which  allowed  us  to  measure 
particle  size  distributions  (and  therefore  respirable  dose) 
under  realistic  conditions  simulating  the  breathing  of  a 
patient.  Any  issues  of  MDI  mistiming  obviously  cannot  be 
addressed  with  a  purely  constant-flow  method. 

The  VFR  technique  can  also  be  used  for  special  cases  in 
which  an  unusual  breathing  pattern  may  affect  respirable 
dose.  Such  cases  might  include  pediatrics  (small  Vy),  re- 
strictive pulmonary  disease  (rapid,  shallow  breathing-^),  or 
mechanical  ventilation. 


Adoption  of  this  technique  for  bench  testing  of  aerosol 
drug  delivery  devices  should  make  it  easier  to  compare 
properties  of  various  drug/device  systems,  as  studied  by 
different  researchers,  under  laboratory  conditions  that 
mimic  the  conditions  of  actual  use  by  a  patient. 


PRODUCT  SOURCES 

Cascade  Impactor 

Andersen  1  ACFM  Non- Viable  Ambient  Particle  Sizing 
Sampler  (Mark  11),  Andersen  Instruments,  Atlanta  GA 
Harvard  Breathing  Machine 

Harvard  Apparatus  Dual  Phase  Control  Respirator  Pump, 
Harvard  Apparatus,  South  Natick  MA 
MDI  Devices 

Airlife  Hand-Held  MediSpacer,  Allegiance  Health- 
care Corporation,  McGaw  Park  IL 

Aerosol  Cloud  Enhancer  (ACE),  Diemolding  Health- 
care Division,  Canastota  NY 

OptiHaler,  HealthScan  Products,  Cedar  Grove  NJ 

AeroChamber,  Monaghan  Medical  Corporation,  Platts- 
burgh  NY 
MDI  Drug 

Ventolin  (albuterol.  United  States  Pharmacopeia),  Allen 
&  Hanburys,  a  Division  of  Glaxo  Wellcome,  Research 
Triangle  Park,  NC 


ACKNOWLEDGMENT 

We  Ihank  Joseph  N  Lix,  who  initially  developed  the  variable  flow  rate 
technique. 


REFERENCES 

1.  Thiel  CG.  From  Susie's  question  to  CFC-free:  an  inventor's  per- 
spective on  forty  years  of  MDI  development  and  regulation.  In: 
Dalby  RN,  Byron  PR,  Farr  SJ,  editors.  Respiratory  drug  delivery  V. 
Buffalo  Grove  IL:  Interpharm  Press;  1996:1 15-12,3. 

2.  Newman  SP,  Pavia  D.  Clarke  SW.  How  should  a  pressurized  /3- 
adrenergic  bronchodilator  be  inhaled?  Eur  J  Respir  Dis  1981:62(1): 
.V2I. 

3.  Sackner  MA,  Kim  CS.  Recent  advances  in  the  management  of  ob- 
structive airways  disease:  auxiliary  MDI  aerosol  delivery  sy.stems. 
Chest  1985:88(2  Suppl):l61S-17()S. 

4.  Hindle  M.  Newton  DAG,  Chrystyn  H.  Investigations  of  an  optimal 
inhaler  technique  with  the  use  of  urinary  salbulamol  excretion  as  a 
measure  of  relative  bioavailability  to  the  lung.  Thorax  199.^:48(6): 
607-610. 

5.  Ivanovich  M,  Kreamer  JW,  Gritzalis  D,  Moses  J.  Evaluation  of  an 
auditory  feedback  equipped  metered  dose  inhaler.  Am  J  Ther  1996; 
.3(12):8 18-820. 

6.  Rau  JL.  Respiratory  care  pharmacology.  5th  ed.  St  Louis:  Mosby- 
Year  Book:  1998:48,.'?84. 

7.  Newman  SP,  Newhouse  MT.  Effect  of  add-on  devices  for  aerosol 
drug  delivery:  deposition  studies  and  clinical  aspects.  J  Aerosol  Med 
l996;9(l):.55-70. 


1484 


Respiratory  Care  •  December  1999  Vol  44  No  12 


In  Vitro  Testing  of  MDI  Spacers 


8.  Dolovich  M,  Ruffin  R,  Corr  D,  Newhouse  MT.  Clinical  evaluation 
of  a  simple  demand  inhalation  MDI  aerosol  delivery  device.  Chest 
1983;84(1):36-41. 

9.  Rachelefsky  GS,  Rohr  AS,  Wo  J,  Gracey  V,  Spector  SL,  Siegel  SC, 
et  al.  Use  of  a  tube  spacer  to  improve  the  efficacy  of  a  metered-dose 
inhaler  in  asthmatic  children.  Am  J  Dis  Child  1986;  140(  1 1):1 191- 
1193. 

1 0.  American  Association  for  Respiratory  Care.  Aerosol  Consensus  State- 
ment—1991.  RespirCare  1991:36(9):916-921. 

1 1 .  Newman,  SP.  Aerosol  deposition  considerations  in  inhalation  ther- 
apy. Chest  1985;88(2  Suppl):l52S-160S. 

1 2.  Dennis  JH,  Hendrick  DJ.  Design  characteristics  for  drug  nebulizers. 
J  Med  Eng  Technol  1992;16(2):63-68. 

13.  Ganderton  D,  Byron  PR.  Harmonising  inhaler  testing  across  the 
pharmacopoeias.  In:  Dalby  RN.  Byron  PR.  Farr  SJ,  editors.  Respi- 
ratory drug  delivery  V.  Buffalo  Grove  IL:  Interpharm  Press;  1996: 
283-292. 

14.  Ahrens  R,  Lux  C,  Bahl  T,  Han  SH.  Choosing  the  metered-dose 
inhaler  spacer  or  holding  chamber  that  matches  the  patient's  need: 
evidence  that  the  specific  drug  being  delivered  is  an  important  con- 
sideration. J  Allergy  Clin  Immunol  l995;96(2):288-294. 

15.  Lix  JN.  Foss  SA,  Keppel  JW.  Simultaneous  measurement  of  mass  dose 
output  and  particle  size  distribution  (aKstract).  In:  AAAR  '97  abstracts. 
Cincinnati:  American  Association  for  Aerosol  Research:  1997:43. 

16.  Foss  SA,  Lix  JL,  Keppel  JW,  English  RE.  Testing  MDI  chamber 
design  under  variable  flow  rate  conditions.  In:  Dalby  RN,  Byron  PR, 
Farr  SJ,  editors.  Respiratory  drug  delivery  VI.  Buffalo  Grove  IL: 
Interpharm  Press;  1998:341-344. 

17.  Spearman  CB,  Sheldon  RL,  Egan  DF.  Egan's  fundamentals  of  re- 
spiratory therapy,  4th  ed.  St  Louis:  CV  Mosby  Co;  1982:165. 

18.  Newman  SP.  Variability  in  drug  delivery  from  aerosol  inhalers  in 


vitro  and  in  vivo.  In:  Dalby  RN,  Byron  PR,  Farr  SJ,  editors.  Respi- 
ratory drug  delivery  V.  Buffalo  Grove  IL:  Interpharm  Press;  1996: 
11-18. 

19.  Stanford  Research  Institute.  Characteristics  of  particles  and  particle 
dispersoids  (chart).  Reprinted  from  Stanford  Research  Institute  Jour- 
nal 1961;  third  quarter. 

20.  Mitchell  JP,  Nagel  MW.  Archer  A.  Mis-timing  between  actuation  of 
a  metered-dose  inhaler  (pMDI)  and  inhalation:  experience  with  a 
valved  holding  chamber  (VHC)  compared  with  a  spacer  (ab.stract). 
RespirCare  1998;43(10):869. 

2 1 .  Rau  JL,  Dunlevy  CL,  Hill  RL.  A  comparison  of  inline  MDI  actuators 
for  delivery  of  a  beta  agonist  and  a  corticosteroid  with  a  mechani- 
cally ventilated  lung  model.  Re.spir  Care  1998;43(9):705-712. 

22.  Finlay  WH.  Inertial  sizing  of  aerosol  inhaled  during  pediatric  tidal 
breathing  from  an  MDI  with  attached  holding  chamber.  Int  J  Pharm 
1998;168:147-152. 

23.  Finlay  WH.  Zuberbuhler  P.  In  vitro  comparison  of  beclomethasone 
and  salbutamol  metered-dose  inhaler  aerosols  inhaled  during  pedi- 
atric tidal  breathing  from  four  valved  holding  chambers.  Chest  1998; 
11 4(6):  1676- 1680. 

24.  Bumell  PKP,  Malton  A,  Reavill  K,  Ball  MHE.  Design,  validation 
and  initial  testing  of  the  Electronic  Lung'"'"  device.  J  Aerosol  Sci 
1998;29(8):101 1-1025. 

25.  National  Asthma  Education  and  Prevention  Program.  Practical  guide 
for  the  diagnosis  and  management  of  asthma.  Bethesda  MD:  Na- 
tional Institutes  of  Health  (NIH  Publication  No.  97-^053);  1997:44. 

26.  Rau  JL.  Respiratory  care  pharmacology,  5th  ed.  St  Louis:  Mosby- 
Year  Book;  1998:285,  287. 

27.  Burton  GG.  Practical  physical  diagnosis  in  respiratory  care.  In:  Bur- 
ton GG,  Hodgkin  JE,  editors.  Respiratory  care,  2nd  ed.  Philadelphia: 
JB  Lippincott;  1984:282-297. 


Respiratory  Care  •  December  1999  Vol  44  No  12 


148- 


Special  Articles 


Possible  Underestimation  of  Shunt  Fraction  in  the 
Hepatopulmonary  Syndrome 

Kevin  McCarthy  RCPT  and  James  K  StoUer  MD 


Estimating  the  right-to-left  shunt  fraction  with  standard  equations  can  be  useful  for  outpatient 
assessment  and  management  of  patients  with  the  hepatopulmonary  syndrome.  However,  because 
the  patient's  true  arteriovenous  oxygen  content  difference  cannot  be  measured  without  invasive 
techniques,  available  equations  for  use  in  outpatient  settings  often  assume  a  value  of  5  mL/dL.  This 
article  examines  the  degree  to  which  assuming  a  value  of  5  mL/dL  for  the  arteriovenous  oxygen 
content  difference  causes  calculated  values  of  the  percent  shunt  to  underestimate  true  values.  Such 
underestimation  can  be  misleading  in  clinical  conditions  such  as  the  hepatopulmonary  syndrome,  in 
which  the  hyperdynamic  circulation  may  be  associated  with  actual  values  of  the  arteriovenous 
oxygen  content  difference  that  are  <  5  mL/dL.  [Respir  Care  1999;44(12):  1486-1488]  Key  words: 
hepatopulmonary  syndrome,  right-to-left  shunt. 


Background 

The  hepatopulmonary  syndrome  (HPS)  is  an  increas- 
ingly recognized  complication  of  chronic  liver  disease, 
and  is  characterized  by  the  presence  of  impaired  oxygen- 
ation and  intrapulmonary  vascular  dilatations.  Though 
various  diagnostic  methods  have  been  employed,  com- 
monly-used techniques  include  contrast-enhanced  echo- 
cardiography, technetium'''"^  macroaggregated  albumin 
scanning  (both  of  which  are  techniques  to  determine  right- 
to-left  shunt),  and  assessment  of  arterial  oxygenation  while 
breathing  100%  oxygen  in  order  to  quantify  the  magnitude 
of  shunt  (often  ascribed  to  a  mechanism  called  diffusion- 
perfusion  impairment  in  HPS).'-  Though  rarely  the  only 
diagnostic  test  performed  in  evaluating  patients  with  sus- 
pected HPS,  a  shunt  determination  is  an  important  com- 
ponent of  the  workup  to  assess  the  magnitude  of  the  shunt 
and  the  effects  of  therapy  (eg,  liver  transplantation). 

Although  the  percent  shunt  fraction  can  be  determined 
directly  during  cardiac  catheterization,  less  invasive  out- 
patient methods  frequently  employ  a  simple  equation  and/or 


Kevin  McCarthy  RCPT  and  James  K  Stoller  MD  are  affiliated  with  the 
Department  of  Pulmonary  and  Critical  Care  Medicine,  The  Cleveland 
Clinic  Foundation.  Cleveland,  Ohio. 

Correspondence:  James  K  Stoller  MD.  Department  of  Pulmonary  and 
Critical  Care  Medicine.  A90.  Cleveland  Clinic  Foundation,  9500  Euclid 
Avenue.  Cleveland  OH  4419.5.  E-mail;  stollej@ccforg. 


nomogram  to  calculate  the  magnitude  of  right-to-left  shunt 
based  on  the  patient's  arterial  oxygen  tension  (P^o,)  while 
breathing  100%  oxygen.'-*  Such  equations,  such  as  that  of 
Chiang,-'  (see  Equation  2  below)  often  assume  an  arterio- 
venous oxygen  content  difference  (C,.,_^,)o,)  of  5  mL/dL, 
an  assumption  that  can  be  erroneous  in  the  setting  of  hepa- 
topulmonary syndrome  and  chronic  liver  disease.  In  these 
settings,  a  hyperdynamic  circulation  occurs  commonly  and 
is  characterized  by  a  high  cardiac  output,  low  systemic 
vascular  resistance,  and  a  subnormal  Cj^.^^o,-  Specifically, 
available  series  suggest  that  the  measured  C,„.^)o,  '"  P''" 
tients  with  chronic  liver  disease  is  approximately  20%  less 
than  the  assumed  value  of  5  mL/dL  (eg,  4.05  mL/dL  among 
10  cirrhotic  patients  reported  by  Kontos  et  al''  [vs  7.85 
mL/dL  in  normal  subjects]  and  3.93  mL/dL  among  13 
cirrhotic  patients  reported  by  Claypool  et  al**). 

Because  such  overestimation  of  the  true  C,.,.^,,q,  will 
introduce  errors  in  the  percent  shunt  value  and  can  thereby 
mislead  clinicians,  we  undertook  the  current  analysis  to 
calculate  the  direction  and  magnitude  of  these  errors,  using 
a  widely  used,  standard  equation.  Specifically,  we  con- 
sider the  effect  of  varying  the  C,,,_„)o,  on  the  magnitude  of 
estimated  shunt  fraction  using  the  widely  used  equation  by 
Chiang.' 

Methods 

The  principle  underlying  the  shunt  calculation  is  that  the 
shunt  fraction  equals  the  ratio  of  oxygen  content  in  shunted 


1486 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Shunt  Fraction  in  Hepatopulmonary  Syndrome 


Q.  20 


a-v  0 ,  content  difference 

27%aiiurtL 
24%  shunt 

21%  shunt 

L 

ie%shtOTt 

fex; 

15%  shunt 

^i.w>^ 

^^^ 

0      100      200      300      400      500      600      700 

Pa02  after  20  min.  of  breathing  100%  02  (mmHg) 

Fig.  1 .  Effect  of  varying  arteriovenous  oxygen  content  difference 
(^(a-vjoj)  on  calculated  shunt  fraction:  relationship  to  arterial  oxy- 
gen tension  on  1 00%  oxygen.  For  identical  arterial  oxygen  tension 
values  w^hile  breathing  100%  oxygen,  higher  values  of  the  arterio- 
venous oxygen  content  difference  cause  the  estimated  shunt  to 
be  lower. 


CO 

£     so- 


il. 

O     20  ■  — 


200 


300 


500 


Alveolar  to  arterial  oxygen  gradient  (mmHg) 

Fig.  2.  Effect  of  varying  arteriovenous  oxygen  content  difference 
on  calculated  shunt  fraction:  relationship  to  alveolar-arterial  oxy- 
gen gradient.  Estimates  of  the  percent  shunt  calculated  using  an 
arteriovenous  oxygen  content  difference  of  5  mL/dL  are  lower  than 
those  using  arterial-venous  oxygen  content  differences  of  3  mUdL 
and  4  mUdL. 


blood  to  the  sum  of  oxygen  content  in  shunted  blood  plus 
blood  traversing  the  pulmonary  vascular  bed.  This  rela- 
tionship is  expressed  in  Equation  1: 


Qs/Qt 


in  which  Qs/Qj  is  shunt  fraction.  Q.q  is  the  oxygen  con- 
tent of  pulmonary  end-capillary  blood,  C,,o,  is  the  arterial 
oxygen  content  of  blood,  and  C^q,  is  the  venous  oxygen 
content  of  blood. 

In  applying  this  equation  in  clinical  practice,  the  oxygen 
content  of  end-capillary  blood  is  calculated  using  the  al- 
veolar Pq,.  Furthermore,  application  of  this  equation  re- 
quires invasive  sampling,  often  with  a  flow-directed  pul- 
monary artery  catheter  to  sample  mixed  venous  blood. 

In  settings  where  measurement  of  shunt  fraction  is  use- 
ful but  where  invasive  monitoring  is  not  possible  (eg,  in 
outpatient  assessment  of  patients  with  chronic  liver  dis- 
ease suspected  to  have  the  hepatopulmonary  syndrome), 
the  equation  published  by  Chiang^  (Equation  2  below)  is 
widely-used.  Because  mixed  venous  blood  is  not  sampled  in 
this  setting,  a  value  for  the  C^^.^^q^  must  be  assumed,  and  is 
most  commonly  assumed  to  be  normal  (ie,  5  mLVdL).  Under 
this  assumption,  the  published  equation  is  Equation  2: 


Qs/Qt 


(^PaO,         '  aO,) 


(Pao,  -  Pao,)  +  1670 


To  calculate  Qs/Qt  with  values  of  the  C(.,.^,)q^  other  than 


5  mL/dL  (Figs.  1  and  2),  we  used  the  more  general  version 
of  the  shunt  equation  (Equation  3): 


Qs/Qt  = 


(P 


AO, 


P,o,)  X  0.003 


[(Pao,  -  Pao,)  X  0.003]  +  (C,o,  -  C,o,) 


in  which  (C^q,  -  C^q,)  is  the  C^ 


a-v)0,' 


To  evaluate  the  impact  of  overestimating  the  C, 


(a-v)O, 


on 


calculating  shunt  fraction  with  Equation  2,  we  calculated 
the  estimated  shunt  fraction  over  a  range  of  P^q,  values  on 
100%  oxygen,  while  varying  the  value  of  the  C(^_^.)o,  in 
Equation  3.  Specifically,  values  of  percent  shunt  were  cal- 
culated over  a  range  of  C(.,.^,)o,  values  (3.5-6.0  mL/dL) 
and  over  a  range  of  P^q,  values  (50-600  mm  Hg)  on  100% 
oxygen. 

Results 

Figure  1  shows  the  family  of  curves  indicating  the  es- 
timated shunt  as  the  C(a_^,)o,  varies  across  values  of  P^q^  on 
100%  oxygen.  Under  the  unnatural  condition  of  no  right- 
to-left  shunt,  all  the  curves  converge,  but  as  the  value  of 
the  ordinate  decreases,  the  curves  diverge  such  that  smaller 
values  of  C(j,.^,)o,  produce  larger  shunt  estimates.  For  ex- 
ample, under  the  condition  of  a  Pj,q^  of  300  mm  Hg,  the 
equation  indicates  a  27%  shunt  when  the  C,.,_^,)o,  is  3 
mL/dL,  a  24%  shunt  when  the  C,„_^.,o,  is  3.5  mL/dL,  and 
a  15%  shunt  when  the  C(a.^,)o,  is  6  mL/dL.  Thus,  in  ap- 
plying this  calculation  to  patients  with  chronic  liver  dis- 
ease (some  of  whom  have  the  hepatopulmonary  syndrome), 
the  degree  of  right-to-left  shunt  will  be  underestimated 


Respiratory  Care  •  December  1 999  Vol  44  No  12 


148 


Shunt  Fraction  in  Hepatopulmonary  Syndrome 


when  the  actual  C,.,,y)o,  f^''^  below  an  assumed  value  of 
5  mL/dL. 

Figure  2  compares  the  shunt  fraction  estimates  using 
varying  0,^.^,0,  o^^''  ^  range  of  values  of  the  alveolar- 
arterial  oxygen  gradient  on  1 00%  oxygen.  As  suggested  by 
the  greater  divergence  of  the  curves  with  increasing  shunt 
fraction,  the  degree  of  underestimation  of  the  true  shunt 
fraction  increases  as  the  true  shunt  increases  and  as  the 


-(a-v)O, 


narrows. 


Discussion 


This  series  of  calculations  shows  that  a  commonly  used, 
simple  equation  for  estimating  the  percent  shunt  fraction 
on  100%  oxygen  will  underestimate  the  actual  shunt  frac- 
tion when  applied  to  patients  whose  true  C,^_^,)o,  is  below 
the  assumed  value  of  5  mL/dL.  Furthermore,  the  degree  of 
underestimation  can  be  large,  even  under  circumstances  in 
which  the  true  C,^_^,o,  is  only  modestly  less  than  5  mL/dL. 

It  is  well  known  that  patients  with  chronic  liver  disease 
have  a  hyperdynamic  circulation  characterized  by  increased 
cardiac  output,  decreased  systemic  vascular  resistance,  and 
decreased  C,„_v)o,-  Specifically,  in  a  series  of  16  cirrhotic 
patients  undergoing  hemodynamic  assessment  by  Kontos 
et  al,''  the  mean  cardiac  output  was  significantly  higher 
than  in  normal  subjects  (mean  8.88  L/min  vs  5.14  L/min, 
p  <  0.01)  and  the  mean  0,^.^,0,  was  significantly  lower 
(4.05  mL/dL  vs  7.85  mL/dL,  p  <  0.001).  Also,  Nakos  et 
aF  found  elevated  values  of  cardiac  output  (9.16  ±  1.76 
L/min)  in  patients  with  hepatic  cirrhosis. 

In  keeping  with  an  earlier  report  by  Harrison  et  al,-*  in 
which  shunt  fractions  in  mechanically  ventilated  patients 


were  underestimated  when  the  C, 


was  overestimated. 


our  findings  serve  as  a  reminder  that  the  shunt  fraction 
estimates  in  patients  with  chronic  liver  disease  can  be 
underestimated  if  values  of  the  Cj^.^^o,  of  5  mL/dL  are 
assumed.  Such  underestimation  of  shunt  fraction  could 


contribute  to  underdiagnosis  of  hepatopulmonary  syn- 
drome. Underestimation  of  the  shunt  fraction  may  also 
account  for  the  discordance  sometimes  observed  between 
the  results  of  imaging  studies  (eg,  contrast-enhanced  echo- 
cardiography or  technetium^^*"  macroaggregated  albumin 
scans)  and  the  calculated  shunt  fraction  values.  Specifi- 
cally, to  the  extent  that  the  estimated  shunt  fraction  falls 
below  the  actual  value,  it  is  possible  that  imaging  studies 
could  support  the  diagnosis  of  HPS,  despite  a  normal  shunt 
fraction  estimate. 

Based  on  these  findings,  we  suggest  that  calculated  val- 
ues of  shunt  fraction  should  be  interpreted  cautiously,  es- 
pecially when  the  calculation  is  based  on  assumed  values 
of  the  C,„_v)o,.  When  clinically  appropriate,  suspicion  of 
the  hepatopulmonary  syndrome  should  prompt  either  cal- 
culation of  the  shunt  fraction  using  values  of  C,;,.v)o,  "^  5 
mL/dL  (ie,  using  Equation  3),  direct  measurement  of  shunt 
fraction,  and/or  use  of  other  diagnostic  modalities. 


REFERENCES 

1.  Lange  PA,  Stoller  JK.  The  hepatopulmonary  syndrome.  Ann  Intern 
Med  1995;122(7):521-.'>29, 

2.  Krowka  MJ,  Cortese  DA.  Hepatopulmonary  syndrome:  current  con- 
cepts in  diagnostic  and  therapeutic  considerations.  Chest  1 994: 1 05(5): 
1528-1537. 

3.  Chiang  ST.  A  nomogram  for  venous  shunt  (Qs/Qt)  calculation.  Tho- 
rax l968;23(5):.563-565. 

4.  Harrison  RA,  Davison  R,  Shapiro  BA,  Meyers  SN.  Reassessment  of 
the  assumed  a-v  oxygen  content  difference  in  the  shunt  calculation. 
Anesth  Analg  1975:54(2):  198-202. 

5.  Kontos  HA,  Shapiro  W.  Mauck  P,  Patterson  JL.  General  and  re- 
gional circulatory  alterations  in  cirrhosis  of  the  liver.  Am  J  Med 
1964:37:526-535. 

6.  Claypool  JG.  Delp  M,  Lin  TK.  Hemodynamic  studies  in  patients 
with  Laennec"s  cirrhosis.  Am  J  Med  Sciences  1957:23:48-55. 

7.  Nakos  G,  Evrenoglou  D.  Vassilakis  N.  Lampropoulos  S.  Haemody- 
namics  and  gas  exchange  in  liver  cirrhosis:  the  effect  of  orally  ad- 
ministered almitrine  bisme.sylate.  Respir  Med  1993;87(2):93-98. 


1481 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Mani  S  Kavuru  MD  and  James  K  Stoller  MD,  Series  Editors 


PFT  Nuggets 


A  66- Year-Old  Woman  with  Longstanding  Dyspnea  on  Exertion 

Niranjan  Seshadri  MD  and  Atul  C  Mehta  MD 


Case  Summary 

A  66-year-oId,  nonsmoker  woman  presents  with  a  4-year 
history  of  dyspnea  on  exertion.  She  denies  cough,  hemop- 
tysis, wheezing,  or  fever/chills.  About  30  years  ago  she 
had  Guillain-Barre  syndrome  with  acute  ventilatory  fail- 
ure, for  which  she  was  intubated  for  about  two  weeks.  She 
currently  uses  a  beta-agonist  inhaler,  with  minimal  or  no 
relief  of  symptoms.  On  physical  examination,  she  has  in- 
spiratory stridor  on  auscultation  over  her  trachea.  Her  car- 
diac exam  is  within  normal  limits  and  her  lungs  are  clear 
to  auscultation.  She  is  without  clubbing.  A  recent  chest 
radiograph  and  a  chest  computed  tomography  (CT)  scan 
were  normal.  Table  1  shows  the  spirometry  results  and 
Figure  1  shows  the  flow-volume  loop  from  this  patient. 

1.  What  is  the  most  likely  diagnosis? 

2.  What  is  the  next  diagnostic  step? 

Discussion 

The  history  of  Guillain-Barre  syndrome  requiring  pro- 
longed intubation,  inspiratory  stridor  on  auscultation,  nor- 
mal chest  radiograph  and  CT  scan,  normal  forced  expira- 
tory volume  in  the  first  second,  normal  forced  vital  capacity, 
normal  ratio  of  forced  expiratory  volume  in  the  first  sec- 
ond to  forced  vital  capacity,  and  an  abnormal  flow-volume 
loop  strongly  indicate  a  diagnosis  of  fixed  upper  airway 
obstruction  (UAO).  Bronchoscopy  showed  a  70-80%  ste- 
nosis of  the  subglottic  trachea. 

Subglottic  and  tracheal  stenosis  can  be  congenital  or 
acquired.  Congenital  types  can  be  membranous  webs, 
closed  first  ring,  or  cartilage  deformity.  The  major  causes 
of  the  acquired  types  are  external  trauma  from  motor  ve- 
hicle accident  and  internal  trauma  from  endotracheal  in- 
tubation, emergency  tracheotomy,  bum  inhalation  injury, 
or  prior  endoscopic  treatment  attempts.  Tracheal  stenosis 


Niranjan  Seshadri  MD  and  Atul  C  Mehta  MD  are  affiliated  with  the 
Department  of  Pulmonary  and  Critical  Care  Medicine,  The  Cleveland 
Clinic  Foundation.  Cleveland.  Ohio. 

Correspondence:  Atul  C  Mehta  MD.  Department  of  Pulmonary  and  Crit- 
ical Care  Medicine.  The  Cleveland  Clinic  Foundation,  9500  Euchd  Av- 
enue, Cleveland  OH  44195.  E-mail:  mehtaal@ccf.org. 


can  also  be  a  manifestation  of  systemic  diseases,  such  as 
amyloidosis,  papillomatosis,  tuberculosis,  and  Wegener's 
granulomatosis. - 

Upper  airway  obstruction  from  subglottic  and  tracheal 
stenosis  is  an  important  clinical  problem  because  of  the 
increase  in  the  number  of  endotracheal  intubations  and 
emergency  medical  procedures  such  as  tracheotomy.  In 
general,  tracheotomy  has  more  complications  than  trans- 
laryngeal  intubation,  and  the  reported  prevalence  of  tra- 
cheal stenosis  ranges  from  5-12%  in  a  number  of  studies. ^ 

The  presentation  of  airway  stenosis  varies  from  asymp- 
tomatic to  life-threatening  situations,  depending  on  the 
degree  of  stenosis  and  anatomic  location,  and  includes 
difficulty  in  clearing  secretions,  hoarseness,  stridor  or 
wheezing,  insidious  dyspnea  on  exertion,  and  respiratory 
failure.  These  symptoms  are  frequently  misdiagnosed  as 
asthma,  congestive  heart  failure,  or  a  recurrence  of  the 
patient's  underlying  problem.^  A  proper  diagnosis  is  made 
more  likely  by  awareness  of  these  complications  and  a 
high  index  of  clinical  suspicion,  aided  by  appropriate  an- 
cillary studies. 

The  chest  radiograph  can  reveal  airway  narrowing  but  is 
not  sensitive.  Other  noninvasive  imaging  techniques  such 
as  magnetic  resonance  imaging  and  CT  scans  are  excellent 
modalities  to  characterize  the  length  of  the  stenotic  seg- 
ment, identify  external  compression,  and  quantify  the  de- 
gree of  anatomic  narrowing. - 

Pulmonary  function  tests  may  indicate  the  presence  of 
UAO  by  the  configuration  of  the  flow-volume  loop  and 
the  measured  flow  rates.  The  flow-volume  loop  data  are 
collected  during  both  inspiration  and  expiration;  by  con- 
vention, expiratory  flow  is  positive  and  inspiratory  flow  is 
negative."  Flow-volume  loops  obtained  with  spirometry 
can  indicate  dynamic  or  fixed  UAO.  In  this  patient,  the 
flow-volume  loop  shows  flattening  of  the  loop  during  both 
inspiration  and  expiration.  Normally,  during  inspiration, 
intrapleural  pressure  is  negative,  so  atmospheric  gas  flows 
into  the  alveoli  across  the  gradient  from  higher  to  lower 
pressures.  In  contrast,  during  exhalation,  the  intrapleural 
pressure  becomes  positive  relative  to  atmospheric  pres- 
sure, and  gas  flows  from  the  lungs  to  the  atmosphere.  Any 
"physiologically"  fixed  obstruction  such  as  tracheal  steno- 
sis produces  a  decrement  in  flows  during  both  inspiration 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1489 


A  66- Year-Old  Woman  with  Longstanding  Dyspnea  on  Exertion 


Table  1 .      Pulmonary  Function  Test  Results 


Test 

Predicted 

LLN 

Measured 

%  Predicted 

FVC(L) 

3.23 

2.56 

3.77 

117 

FEV,  (L) 

2.48 

1.92 

2.90 

117 

FEV|/FVC 

76.0 

67.0 

77.0 

— 

PEE  (L/sec) 

2.23 

0.87 

7.97 

136 

^^^50% 

5.85 

4.12 

3.91 

122 

FIF,o* 

3.20 

2.03 

5.02 

— 

FEF/HF 

— 

— 

78.0 

— 

FET  (sec) 

— 

— 

9.47 

— 

Predicted  =  Mean  predicted  values  per  Crapo  et  al.' 

LLN  =  Lower  limit  of  normal,  the  value  as  the  lower  fifth  percentile  of  the  normal  range. 

FVC  =  Forced  vital  capacity. 

FEV|  =  Forced  expiratory  volume  in  the  first  second. 

FEV, /FVC  =  Ratio  of  FEV,  to  FVC. 

PEF  =  Peak  expiratory  flow  (in  liters/secl. 

FEF  50'5  -  Forced  expiratory  flow  at  50%  of  the  FVC. 

FIF  so**  -  Forced  inspiratory  flow  at  50%  of  the  FVC. 

FEF/FIF  =  Expressed  as  a  percent. 

FET  -  Forced  expiratory  time  (seconds). 


and  expiration.  Spirometry  evidence  of  expiratory  obstruc- 
tion is  seen  as  a  flattening  of  the  expiratory  (positive)  limb 
of  the  flow-volume  loop,  and  inspiratory  obstruction  is 
seen  as  a  flattening  of  the  inspiratory  (negative)  limb.''  In 
contrast  to  fixed  UAO,  there  can  be  a  dynamic  intratho- 
racic or  extrathoracic  airway  obstruction  that  produces 
slightly  different  patterns  on  the  flow-volume  loop.  In  the 
case  of  dynamic  extrathoracic  airway  obstruction,  there  is 
a  relative  flattening  of  the  inspiratory  limb  of  the  flow- 
volume  loop  because  the  airways  tend  to  collapse  with 
inspiration  (tracheal  pressure  is  less  than  atmospheric  pres- 
sure). Thyroid  goiter,  tracheomalacia,  and  vocal  cord  pa- 
ralysis are  examples.  Dynamic  intrathoracic  airway  ob- 
struction causes  a  flattening  of  the  expiratory  limb  of  the 
flow-volume  loop  because  the  intrathoracic  airways  tend 
to  collapse  with  expiration  (tracheal  pressure  is  less  than 
intrapleural  pressure).  Endobronchial  carcinoid  at  the  level 
of  the  carina,  tracheomalacia,  and  other  tumors  straddling 
the  carina  are  examples  of  variable  intrathoracic  UAO.-'' 

The  accepted  standard  for  assessing  upper  airway  ob- 
struction is  flexible  bronchoscopy,  which  enables  proper 
anatomic  classification  and  assessment  of  the  cause  and 
degree  of  stenosis.  The  treatment  strategy  depends  on  the 
information  obtained  through  flexible  bronchoscopy. - 

Currently,  no  single  therapeutic  modality  has  been  found 
to  be  uniformly  effective  for  treating  tracheal  stenosis.  In 
the  past,  therapies  such  as  electrocautery,  cryotherapy,  and 
bougie  dilation  resulted  in  unpredictable  healing  and  sub- 
stantial failure  rates.  The  mainstay  of  management  is  en- 


8 
6 
4 

•o   2 

m 

I 


-2 

-4 
-6 

-8 

Fig.  1.  Flow-volume  loop. 


Expiratory 


Inspiratory 


doscopic  or  open  surgery  with  resection  and  end-to-end 
anastomosis.  Endoscopic  procedures  aim  to  preserve  the 
epithelium  and  minimize  thermal  and  mechanical  mucosal 
injury.  A  multimodality  approach  is  usually  preferred  and 
may  include  using  carbon  dioxide  laser,  argon  laser,  or 
neodynium-aluminum-gamet  laser  photodissections,  gen- 
tle dilation,  indwelling  stents,  or  mucosal  sparing  tech- 
niques. Several  large  series  of  endoscopic  management  of 
airway  stenosis  have  been  published,  with  success  rates 
ranging  from  57-89%.^  A  successful  endoscopic  outcome 
largely  depends  on  proper  patient  selection.  Open  surgical 
reconstruction  is  indicated  when  unfavorable  findings  pre- 
clude endoscopic  intervention  or  conservative  approaches 
have  been  unsuccessful.  Surgery  involves  resection  of  the 
stenotic  segment  and  restoring  the  circular  architecture 
over  which  respiratory  epithelium  can  regenerate.  There 
isa  large  disparity  in  the  results  reported  for  the  open  sur- 
gical technique,  with  failure  rates  ranging  from  4-27%. 
This  variation  is  probably  related  to  surgical  technique  and 
patient  selection. ^ 


REFERENCES 


1.  Crapo  RO.  Morris  AH.  Gardner  RM.  Reference  spirometric  values 
using  techniques  and  equipment  that  meet  ATS  recommendations. 
Am  Rev  Respir  Dis  1981:I23(6):659-664. 

2.  Mehta  AC,  Harris  RJ.  De  Boer  GE.  Endoscopic  management  of 
benign  airway  stenosis.  Clin  Chest  Med  I995;I6(3):40I^I3. 

3.  Kavuru  MS.  Eliachar  I.  Sivak  ED.  Management  of  the  upper  airway 
in  the  critically  ill  patient:  the  high  risk  patient  management  of  the 
critically  ill.  3rd  edition.  Baltimore:  Williams  &  Wilkins;  1995.  Pgs 
189-211. 

4.  Stoller  JK.  Spirometry:  a  key  diagnostic  test  in  pulmonary  medicine. 
Cleve  Clin  J  Med  1992;.59(l):75-78. 

5.  Golish  JA.  Ahmad  M.  Yarnal  JR.  Practical  application  of  the  flow- 
volume  loop.  Cleve  Clin  Q  1980;47(l):39-^5. 


149U 


Respiratory  Care  •  December  1999  Vol  44  No  12 


A  71 -Year-Old  Man  With  Progressive  Shortness  of 
Breath  and  Orthopnea 


Loutfi  S  Aboussouan  MD 


Case  Summary 


Discussion 


A  71-year-old  white  man  had  an  11-month  history  of 
progressive  shortness  of  breath  and  weakness.  He  pre- 
sented to  the  pulmonary  clinic  with  symptoms  of  orthop- 
nea, hypersomnolence,  mild  dysarthria,  and  dysphagia  of 


The  pulmonary  function  tests  suggest  a  severe  restric- 
tive impairment  and  show  decreased  respiratory  muscle 
strength.  The  marked  decrease  in  supine  pulmonary  func- 
tion is  consistent  with  diaphragmatic  weakness.  The  pro- 


Table  1 .      Pulmonary  Function  Test  Results 

Test                           Predicted 

Sitting 

Supine 

%  Change 

Measured 

%  Predicted 

Measured 

%  Predicted 

(sitting-supine) 

FVC  (L)  4.05 

FEV,  (L)  3.14 

FEV|/FVC  0.78 

MIP  (cm  H,0)  104 

MEP  (cm  H,0)  196 

Predicted  =  Mean  predicted  values  per  Crapo  et  al.' 

FVC  =  forced  vital  capacity. 

FEV]  =  forced  expiratory  volume  in  the  first  second. 

FEV, /FVC  =  ratio  of  FEV,  to  FVC. 

MIP  =  maximal  inspirator)'  pressure  (cm  H^O). 

MEP  =  maximal  expirator\'  pressure  (cm  H-'O). 


1.79 
1.39 
0.78 
24 
54 


44 
44 
100 
23 


1.32 
0.96 
0.73 


33 
31 
94 


-26 
-31 


one  month's  duration.  He  was  a  remote  5  pack-year  smoker 
and  denied  any  history  of  asthma  or  emphysema.  Physical 
examination  was  remarkable  for  the  presence  of  abdomi- 
nal paradox  and  the  use  of  accessory  muscles.  Fascicula- 
tions  were  noted  over  the  shoulders  and  upper  extremities. 
Table  1  shows  the  results  of  pulmonary  function  tests. 

Arterial  blood  gases  on  room  air  were:  pH  7.42,  P^o,  48 
mm  Hg,  Pq^  75  mm  Hg,  and  Hqq^  31  mEq/L. 

What  is  your  diagnosis? 


Loutfi  S  Aboussouan  MD  is  affiliated  with  the  Department  of  Pulmonary 
and  Critical  Care  Medicine.  Harper  Hospital.  Wayne  State  University. 
Detroit  Michigan. 

Correspondence:  Loutfi  S  Aboussouan  MD.  Department  of  Pulmonary 
and  Critical  Care  Medicine.  Harper  Hospital.  Wayne  State  University. 
3990  John  R  Street,  Detroit  MI  48201.  E-mail:  laboussouan@intmed. 
wayne.edu. 


gressive  nature,  presence  of  bulbar  symptoms,  and  phys- 
ical findings  raise  the  possibility  of  amyotrophic  lateral 
sclerosis  (ALS),  and  this  diagnosis  was  ultimately  con- 
firmed by  clinical  and  electrophysiological  examination. 
This  patient  had  ALS  with  respiratory  symptoms  as  a  pre- 
senting feature.  The  patient's  course  was  characterized  by 
poor  tolerance  of  noninvasive  positive  pressure  ventila- 
tion. He  declined  invasive  options  and  died  about  1 8  months 
after  the  first  onset  of  his  symptoms. 

Sitting  and  supine  spirometry  is  useful  in  the  evaluation 
of  diaphragmatic  function.  A  5-10%  difference  in  forced 
vital  capacity  between  sitting  and  supine  positions  (lower 
in  supine  position)  can  be  expected  in  normal  subjects. 
Sitting- versus-supine  differences  of  10-20%  may  be  seen 
with  obesity  and  unilateral  diaphragmatic  paralysis.  Even 
larger  differences  are  seen  in  diaphragmatic  weakness,  as 
is  illustrated  in  the  present  case.  Patients  with  bilateral 
diaphragmatic  paralysis  show  a  40-50%  decrease  in  vital 
capacity  upon  assuming  the  supine  position. - 


Respiratory  Care  •  December  1999  Vol  44  No  12 


149' 


A  71-Year-Old  Man  With  Progressive  Shortness  of  Breath  and  Orthopnea 


ALS  is  a  progressive  and  uniformly  fatal  neuromuscular 
disease,  with  death  usually  being  secondary  to  respiratory 
complications.''  However,  shortness  of  breath  is  rarely  the 
presenting  symptom  of  ALS."*  This  presentation  usually 
portends  a  poor  prognosis  and  rapid  progression.  Pathol- 
ogy resuhs  may  reveal  a  predominance  of  lesions  in  the 
anterior  horn  cells  of  the  C3  to  C7  cervical  region,  corre- 
sponding to  the  phrenic  nuclei.'*  "^  In  our  experience,  only 
about  5%  of  patients  ultimately  diagnosed  to  have  ALS 
report  pulmonary  symptoms  as  a  presenting  feature.  Nev- 
ertheless, pulmonary  and  critical  care  physicians  are  likely 
to  see  these  patients  before  a  diagnosis  is  obtained,  and 
should  therefore  consider  the  possibility  of  ALS  in  the 
appropriate  clinical  setting.  For  instance,  features  that  may 
raise  the  suspicion  for  a  neuromuscular  disorder  as  a  cause 
for  respiratory  insufficiency  include:  (1)  absence  of  a 
chronic  cardiopulmonary  disorder,  (2)  relatively  normal 


physical  exam,  electrocardiogram,  and  chest  radiograph, 
and  (3)  rapid  improvement  with  ventilatory  support  and 
subsequent  difficulty  in  weaning.''-^ 

REFERENCES 

1.  Crapo  RO,  Morris  AH,  Gardner  RM.  Reference  spirometric  values 
using  techniques  and  equipment  that  meet  ATS  recommendations. 
Am  Rev  Respir  Dis  1981;123(6):659-664. 

2.  Loh  L,  Goldman  M,  Davis  JN.  The  assessment  of  diaphragm  func- 
tion. Medicine  (Baltimore)  1977;.i6: 165-169. 

3.  Caroscio  JT,  Mulvihill  MN,  Sterling  R,  Abrams  B.  Amyotrophic 
lateral  sclerosis:  its  natural  history.  Neurol  Clin  1987;5(l):l-8. 

4.  Meyrignac  C,  Poirier  J,  Degos  JD.  Amyotrophic  lateral  sclerosis 
presenting  with  respiratory  insufficiency  as  the  primary  complaint: 
clinicopathological  study  of  a  case.  Eur  Neurol  1985;24(2):1 15-120. 

5.  Fromm  GB,  Wisdom  PJ,  Block  AJ.  Amyotrophic  lateral  sclerosis 
presenting  with  respiratory  failure:  diaphragmatic  paralysis  and  de- 
pendence on  mechanical  ventilation  in  two  patients.  Chest  1977; 
71(5):612-614. 


1492 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Letters  addressing  topics  of  current  interest  or  material  in  RESPIRATORY  CARE  will  be  considered  for  publication.  The  Editors  may  accept  or 
decline  a  letter  or  edit  without  changing  the  author's  views.  The  content  of  letters  as  published  may  simply  reflect  the  author's  opinion  or  inter- 
pretation of  information — not  standard  practice  or  the  Journal's  recommendation.  Authors  of  criticized  material  will  have  the  opportunity  to 
reply  in  print.  No  anonymous  letters  can  be  published.  Type  letter  double-spaced,  mark  it  "For  Publication,"  and  mail  it  to  RESPIRATORY 
CARE,  600  9th  Avenue.  Suite  702,  Seattle  WA  98104. 


Letters 


Vital  Capacity  Maneuver  in  Modifled 
Spirometry  Teciinique 

I  was  interested  to  read  the  article  by 
James  K  StoUer  et  al  [Respir  Care  1999: 
44(4):44 1 -442]  concerning  the  modified 
spirometry  technique  in  patients  with  chronic 
obstructive  lung  disease.  I  have  used  this 
technique  myself  on  this  patient  group  and 
noticed  the  significant  improvement  in  forced 
vital  capacity  (FVC).  However,  I  have 
thought  long  and  hard  whether  we  should 
report  the  total  exhaled  volume  measured 
using  this  technique  as  FVC  or  simply  as  vital 
capacity.  One  could  argue  that  it  is  not  a  full 
forced  maneuver  (nor  is  it  a  slow  vital  capac- 
ity [SVC],  although  in  my  experience  the 
results  using  this  technique  closely  reflect 
the  "true"  SVC  maneuver).  As  the  difference 
between  FVC  and  SVC  is  considered  one 
method  of  determining  air  trapping  (in  the 
absence  of  total  lung  capacity  measure- 
ments), careful  consideration  should  be  given 
to  exactly  what  we  call  the  volume  obtained 
using  this  modified  spirometry  technique. 

Brenton  Eckert  MSc 

Department  of  Respiratory  Medicine 

PA  Hospital 

Brisbane 

Queensland,  Australia 

The  authors  respond: 

We  thank  Mr  Eckert  for  his  thoughtful 
comment  regarding  the  modified  spirome- 
try technique  and  his  question  regarding  the 
preferred  name  for  the  vital  capacity  maneu- 


ver using  this  technique.  Based  on  obser- 
vations made  when  we  first  described  this 
technique  (Am  Rev  Respir  Dis  1993; 
148:275-280),  we  agree  with  Mr  Eckert  that 
the  vital  capacity  maneuver  performed  using 
a  modified  spirometry  technique  generates 
values  closer  to  a  slow  vital  capacity  than 
the  traditional  forced  vital  capacity.  Specif- 
ically, in  a  group  of  48  patients  evaluated  in 
a  crossover  trial  using  both  techniques,  a  vital 
capacity  obtained  with  a  modified  spirom- 
etry technique  was  significantly  higher  than 
the  forced  vital  capacity  obtained  using  a 
standard  technique,  especially  in  individu- 
als with  more  severe  airflow  obstruction. 
Indeed,  in  a  group  of  12  patients  whose  ratio 
of  forced  expiratory  volume  in  the  first  sec- 
ond to  forced  vital  capacity  (FEV|/FVC)  was 
<  0.45  (based  on  a  standard  FVC  maneu- 
ver), the  vital  capacity  obtained  with  the 
modified  technique  (mean  2.62  ±  0.76  L)  was 
significantly  higher  than  the  standard  forced 
vital  capacity  (mean  2.29  ±  0.72  L,  p  = 
0.(X)7).  As  might  be  expected,  the  difference 
between  the  modified  vital  capacity  and  the 
standard  forced  vital  capacity  was  smaller 
in  individuals  with  less  severe  airflow 
obstruction,  but  the  difference  was  statisti- 
cally significant  for  all  patients  whose 
FEV|/FVC  ratio  was  <  0.74. 

On  the  basis  of  these  initial  observations 
and  subsequent  confirmatory  experience,  we 
agree  widi  Mr  Eckert's  statement  that  "care- 
ful consideration  should  be  given  to  exactly 
what  we  call  the  volume  obtained  using  this 
modified  spirometry  technique."  Though  we 
have  not  previously  proposed  such  a  title. 


perhaps  the  designation  "FVCmodified"  is 
appropriate. 

Mr  Eckert's  comment  about  the  rela- 
tionship between  FVC  and  SVC  raises  one 
other  point  de.serving  comment.  Although 
the  difference  between  the  SVC  and  FVC 
is  somefimes  ascribed  to  air  trapping  in 
patients  with  airflow  obstruction,  in  severely 
obstructed  patients  the  difference  may  be 
only  due  to  the  difference  in  the  amount  of 
time  that  the  patient  can  maintain  an  expi- 
ration under  differing  conditions  (ie,  the  hard 
push  versus  the  gentle  push).  In  the  context 
of  evaluating  spirograms  from  37  clinical 
centers  in  the  Registry  for  Patients  with 
Alpha  1-AnUtrypsin  Deficiency,  we  noted 
that  only  rarely  did  the  volume-time  tracing 
plateau,  even  when  the  expiration  exceeded 
15  seconds.  This  raises  the  question  of 
whether  true  "air  trapping"  occurs  in  the  con- 
text of  the  FVC  maneuver.  As  there  are  no 
time  standards  for  the  SVC  and  no  reported 
expiratory  times,  the  evaluation  of  the 
SVC-FVC  difference  becomes  difficuh  and, 
in  our  view,  of  limited  clinical  value. 

We  appreciate  Mr  Eckert's  thoughtful 
remarks. 

James  K  Stoller  MD 
Daniel  Laskowski  RPFT 
Kevin  McCarthy  RCPT 

Department  of  Pulmonary  and 

Critical  Care  Medicine 

The  Cleveland  Clinic  Foundation 

Cleveland,  Ohio 


Respiratory  Care  •  December  1999  Vol  44  No  12 


149.^ 


Listing  and  Reviews  of  Books  and  Otiier  Media.  Nole  to  publishers:  Send  review  copies  of  books, 
films,  tapes,  and  software  to  Rhspiratory  Care,  600  Ninth  Avenue,  Suite  702,  Seattle  WA  98104. 


Books,  Films, 
Tapes,  &  Software 


Interpretation  of  Pulmonary  Function 
Tests:  A  Practical  Guide.  Robeil  E  Hyatt 
MD.  Paul  D  Scanlon  MD.  and  Masao  Na- 
kamura  MD.  Philadelphia:  Lippincott- 
Raven  F^iblishers.  1997.  Soft-cover,  illus- 
trated, 212  pages,  $39.95. 

Interpretation  of  Pulmonary  Function 
Tests:  A  Practical  Guide  provides  a  valu- 
able resource  for  anyone  involved  in  pul- 
monary diagnostic  testing.  The  aim  of  the 
book  is  to  give  readers  a  concise  description 
of  the  most  commonly  ordered  pulmonary 
function  tests  (PFTs)  used  in  the  manage- 
ment of  patients  with  pulmonary  disease. 
The  text  focuses  on  the  conceptual  basis  for 
each  test,  when  a  particular  test  should  be 
ordered,  and  how  the  results  of  the  test  can 
be  used  in  the  management  of  patients.  The 
authors  emphasize  that  the  book  is  not  in- 
tended to  serve  as  a  manual  on  how  to  per- 
form the  tests.  The  intended  audience  is  pri- 
marily practicing  physicians  and  pulmonary 
function  technologists,  but  health  science 
students  in  respiratory  therapy,  medicine, 
and  nursing  will  also  find  this  book  useful. 

The  book  is  divided  into  13  chapters, 
which  are  well  written  and  amply  illustrated 
with  figures  and  tables  that  enhance  the  text. 
The  authors  have  interspersed  "pearls" 
throughout  the  text  as  a  means  of  sharing 
their  personal  insight  into  the  various  nu- 
ances that  one  may  encounter  when  inter- 
preting PFTs.  These  pearls  are  interesting, 
and  they  provide  information  that  is  not  al- 
ways obvious  when  analyzing  tests  results. 

The  first  part  of  the  book  focuses  on  var- 
ious tests  that  are  used  to  assess  the  me- 
chanics of  breathing,  diffusing  capacity  of 
the  lung,  bronchial  challenge,  and  arterial 
blood  gases.  Chapters  on  specialized  tests, 
such  as  resistance  and  compliance  measure- 
ments and  exercise  capacity,  are  also  in- 
cluded. The  chapters  on  spirometry,  lung 
volume  measurements,  and  bronchial  chal- 
lenge are  particularly  well  done.  They  are 
concisely  written,  and  the  reader  will  find 
the  information  on  the  mechanics  of  breath- 
ing very  useful.  This  is  not  surprising  when 
one  considers  that  Hyatt  and  his  colleagues 
helped  lay  the  foundation  for  our  present 
approach  to  spirometry  and  pulmonary  func- 
tion testing  with  the  introduction  of  the  con- 
cept of  flow-volume  analysis.  The  chapters 


on  diffusing  capacity,  resistance  and  com- 
pliance measurements,  and  distribution  of 
ventilation  are  also  well-written,  but  the 
chapter  on  arterial  blood  gases  is  somewhat 
limited.  The  descriptions  of  acid-base  dis- 
turbances are  adequate,  but  the  addition  of 
more  case  studies  to  demonstrate  how  cer- 
tain blood  gas  patterns  occur  in  individuals 
with  pulmonary  dysfunction  would  have  en- 
hanced the  chapter. 

The  second  part  of  the  book  contains  a 
chapter  on  preoperative  PFT,  a  chapter  that 
describes  how  to  interpret  PFTs,  and  a  chap- 
ter that  summarizes  common  patterns  seen 
in  patients  with  pulmonary  diseases.  The 
authors  encourage  the  reader  to  use  a  gestalt 
approach  to  interpreting  PFTs.  in  which  the 
clinician  visually  compares  the  individual 
flow-volume  curve  to  the  normal  predicted 
curve.  This  approach  is  easy  to  understand 
and  provides  a  useful  first  step  in  analyzing 
PFTs.  Once  it  has  been  established  that  an 
obstructive  or  restrictive  pattern  is  present, 
the  clinician  can  then  apply  information  from 
other  PFTs  to  better  define  the  patient's  con- 
dition. 

The  final  chapter  of  the  book  presents  32 
illustrative  cases  of  patients  with  various 
types  of  pulmonary  dysfunction.  This  chap- 
ter gives  the  reader  an  opportunity  to  test 
his  or  her  ability  to  interpret  commonly- 
encountered  PFTs.  The  cases  are  well  cho- 
sen and  the  information  presented  is  well 
organized  and  easy  to  follow.  Although  in 
these  case  reports  the  authors  did  not  in- 
clude arterial  blood  gas  reports  on  data  from 
specialized  tests  such  as  resistance  and  com- 
pliance measurements  and  exercise  tests,  the 
cases  are  illustrative  of  the  most  common 
abnormalities  one  encounters  in  a  PFT  lab- 
oratory. 

Overall,  I  found  the  book  to  be  well  or- 
ganized and  written  in  a  manner  that  al- 
lowed the  reader  to  become  proficient  in 
interpreting  basic  PFTs.  The  authors'  em- 
phasis on  tests  of  the  mechanics  of  breath- 
ing seems  appropriate  considering  that  these 
tests  form  the  foundation  for  PFT. 

J  M  Cairo  PhD  RRT 

Department  of  Cardiopulmonary  Science 

School  of  Allied  Health  Professions 

Louisiana  State  University 

New  Orleans,  Louisiana 


The  Handbook  of  Critical  Care  Drug 
Therapy,  2nd  edition.  Gregory  M  Susla 
PhamiD.  Henry  Masur  MD,  Robert  E  Cun- 
nion  MD,  Anthony  F  Suffredini  MD,  Fred- 
erick P  Ognibene  MD,  William  D  Hoffman 
MD.  James  H  Shelhamer  MD.  Baltimore, 
Maryland:  Williams  &  Wilkins.  1998.  Soft- 
cover,  436  pages,  24.95. 


This  is  the  second  edition  of  a  quick- 
reference  manual  focused  on  drug  use  in  the 
intensive  care  setting.  One  hundred  twenty- 
three  tables  and  7  figures  comprise  the  en- 
tire contents  of  the  book.  The  tables  are 
organized  according  to  1 3  broad  critical  care 
topics,  including  acute  resuscitation,  anes- 
thesia topics,  poisonings,  drug  monitoring, 
and  the  organ-system-specific  disciplines 
encountered  most  frequently  in  the  inten- 
sive care  unit  (ICU).  Within  the  limits  of  a 
tabular  fonnat,  the  volume  presents  a  com- 
prehensive summary  of  therapeutic  options, 
with  abbreviated  information  on  indications, 
dose  ranges,  administration  guidelines,  pre- 
cautions, and  assorted  "pearls"  in  the  com- 
ments column.  The  information  is  fairiy  cur- 
rent, though  some  agents  added  to  the  ICU 
armamentarium  in  recent  years  seem  to  be 
missing  (eg,  fenoldopam,  trovafloxacin,  in- 
sulin lispro). 

The  target  audience  is  physicians,  but  oth- 
ers who  work  predominantly  in  the  critical 
care  setting  may  find  it  useful  as  well.  The 
book  utilizes  3  table  formats:  li.sts  of  disease 
entities  and  options  for  therapy,  lists  of  drugs 
with  indications  for  use,  dose  ranges,  and 
side  effects,  and  3  appendixes  that  provide 
guidelines  for  intravenous  and  oral  admin- 
istration of  drugs  in  the  ICU,  as  well  as 
intravenous-to-oral  conversions.  Most  of  the 
drug  tables  do  not  make  specific  recom- 
mendations for  therapy,  but  instead  simply 
list  agents  that  might  be  considered.  Tables 
in  the  hematologic  therapies  chapter  are  par- 
ticularly well  consUTicted,  with  solid  rec- 
ommendations and  up-to-date  information 
on  component  therapies,  immune  globulin 
products,  and  treatment  of  thrombotic  dis- 
orders. The  infectious  diseases  chapter  is 
made  up  of  thorough,  well  organized  tables 
recommending  primary  and  alternate  ther- 
apies by  organism,  as  well  as  by  infection 


149h 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Book,  Films,  Tapes,  &  Software 


syndromes  encountered  in  the  ICU.  Simi- 
larly, the  chapter  on  poisonings  is  compre- 
hensive and  detailed,  with  solid  recommen- 
dations and  plenty  of  valuable  information 
in  the  comments  column. 

Respiratory  therapists  will  find  the  well- 
organized  section  on  advanced  cardiac  life 
support  and  the  anesthesia  chapter  particu- 
larly helpful.  Unfortunately,  the  12-page 
chapter  on  pulmonary  therapies  is  one  of 
the  shortest  in  the  book  and  provides  only 
superficial  coverage  of  the  topic.  This  is 
particularly  disappointing,  given  that  respi- 
ratory illnesses  constitute  a  major  portion  of 
the  patient  population  in  most  critical  care 
units.  Asthma  has  a  single  page  reference  in 
the  index,  and  chronic  obstructive  pulmo- 
nary disease  is  not  mentioned.  The  issue 
of  nebulizer  delivery  versus  metered-dose- 
mhaler  delivery  of  bronchodilators  for  me- 
chanically ventilated  patients  is  not  ad- 
dressed. The  MDI  doses  cited  are  very 
conservative  for  critical  care.  There  are  rec- 
ommendations regarding  intravenous  corti- 
costeroid therapy,  but  there  is  no  mention 
of  oral  therapy  in  this  section,  and  inhaled 
anti-inflammatory  agents  are  not  men- 
tioned at  all.  Coverage  of  theophylline 
therapy  is  good,  provided  the  reader  has 
additional  knowledge  about  symptoms  of 
toxicity,  toxic  serum  levels,  and  how  to 
avoid  them.  If  not,  a  jump  to  Page  294  is 
necessary  to  get  more,  but  still  incom- 
plete, informafion.  Age  precautions  are  not 
mentioned. 

The  presentation  is  adequate,  and  orga- 
nization by  topic  is  clear.  The  index  is  quite 
thorough,  perhaps  too  thorough  for  a  "quick- 
reference"  book.  When  searching  for  infor- 
mation on  propranolol,  one  is  directed  to  8 
different  tables  in  6  sections  of  the  book. 
There  are  9  separate  table  citations  for  the- 
ophylline, 14  for  phenytoin,  and  45  for  van- 
comycin, without  highlighting  or  subcatego- 
rization  to  focus  the  reader's  search.  The 
editors  have  made  a  point  of  referencing 
drugs  by  both  generic  and  brand  names  in 
the  index,  but  this  does  not  carry  over  to  the 
tables  themselves,  where  strictly  generic 
names  are  used. 

The  clinician  using  this  book  on  a  daily 
basis  will  find  it  useful  as  a  quick  ICU  ref- 
erence for  dosing  guidelines  and  treatment 
recommendations,  at  least  for  selected  top- 
ics. Those  who  pick  it  up  less  frequently  or 
who  may  not  be  familiar  with  its  intent  and 
organization  will  be  frustrated  with  the  time 


it  takes  to  extract  a  relatively  small  amount 
of  information  from  its  pages. 

Richard  J  Maunder  MD 

Department  of  Critical  Care  Services 
Providence  Portland  Medical  Center 

Keith  Hyde  MBA  RRT 

Respiratory  Care  Services 

Providence  Health  System 

Portland,  Oregon 

Rehabilitation  of  the  Patient  with  Respi- 
ratory Disease.  Neil  S  Chemiack  MD,  Mur- 
ray D  Altose  MD,  Ikuo  Homma  MD.  New 
York:  McGraw-Hill.  1999.  Hardcover,  il- 
lustrated, 724  pages,  $115.00. 

The  first  (and  still  valid)  definition  of 
pulmonary  rehabilitation  was  made  by  a 
committee  of  the  American  College  of  Chest 
Physicians  25  years  ago:  they  defined  it  as 
"an  art  of  medical  practice  wherein  an  in- 
dividually tailored  multidisciplinary  pro- 
gram is  formulated,  which,  through  accu- 
rate diagnosis,  therapy,  emotional  support, 
and  education,  stabilizes  or  reverses  both 
the  physio-  and  psychopathology  of  pulmo- 
nary diseases  and  attempts  to  return  the  pa- 
tient to  the  highest  possible  functional  ca- 
pacity allowed  by  his/her  pulmonary 
handicap  and  overall  life  situation."'  Since 
then,  pulmonary  rehabilitation  has  become 
widely  accepted,  and  different  settings  have 
developed,  namely  hospitals,  the  outpatient 
clinic,  and  the  home.  Team  composition 
tends  to  differ  in  the  different  settings,  hos- 
pital teams  being  more  likely  to  include  more 
professionals  and  to  have  more  consultation 
services  available  than  outpatient  or  home 
settings. 

Because  of  the  multiprofessional  nature 
of  rehabilitation,  handbooks  for  rehabilita- 
tion of  the  respiratory  disease  patient  have 
to  discuss  the  science  and  art  of  rehabilita- 
tion from  many  different  perspectives;  that 
is,  they  have  to  give  a  broad  view.^  This 
book  fulfills  these  criteria  and  brings  to- 
gether a  body  of  knowledge  that  should  be 
of  interest  to  all  those  working  or  planning 
to  work  in  pulmonary  rehabilitation.  The 
book  consists  of  62  short  chapters  (ranging 
from  3  to  35  pages),  divided  into  7  parts. 
The  first  two  parts  are  devoted  to  the  phys- 
iologic foundations  and  pathophysiology, 
and  comprise  generally  well-written  reviews 
with  a  good  number  of  references.  At  first 
glance,  some  of  the  content  here  seems  to 
require  a  good  basic  knowledge  of  physiol- 
ogy, such  as  Chapter  2  dealing  with  gas 


exchange,  wherein  49  equations  are  intro- 
duced. The  reader  should  not  be  discour- 
aged by  this,  however,  because  the  material 
is  well  explained  in  this  chapter,  as  else- 
where. And  if  the  reader  is  not  interested  in 
the  topic  of  these  two  parts,  they  can  easily 
be  skipped  without  causing  any  problems  in 
reading  the  following  chapters.  Parts  3 
through  6  handle  patient  assessment  in  pul- 
monary rehabilitation,  general  treatment 
considerations,  specific  disease  manage- 
ment, and  psychosocial  considerations. 

The  disadvantage  of  having  so  many  short 
chapters  is  the  overlap  and  repetition  of  some 
topics,  and  the  advantage  is  that  the  reader 
can  be  very  selective  about  what  chapters  to 
read,  without  losing  the  thread.  Some  over- 
laps could  have  been  avoided,  however,  such 
as  the  issue  of  electrical  stimulation  of  ven- 
tilatory muscles,  which  is  described  and  dis- 
cussed in  two  chapters  (30  and  44).  It  would 
also  have  been  convenient  to  connect  the 
two  chapters  (43  and  5 1 )  covering  lung  vol- 
ume reduction  surgery  in  Japan  and  the 
United  States. 

Notwithstanding  these  minor  defects, 
more  or  less  all  the  chapters  are  well  writ- 
ten, concise,  and  up-to-date  reviews  of  all 
the  different  topics  discussed.  Not  only  is 
assessment  and  management  of  obstructive 
and  restrictive  pulmonary  diseases  handled, 
but  also  neuromuscular  diseases  and  inju- 
ries (which  have  major  effects  on  the  respi- 
ratory system),  lung  cancer,  and  the  specific 
problems  of  pediatric  pulmonary  rehabilita- 
tion. Abundant  figures  and  tables  are  pro- 
vided, many  of  them  being  very  practical 
for  the  physician,  nurse,  or  therapist  work- 
ing actively  in  rehabilitation.  A  good  exam- 
ple of  such  practicality  is  Chapter  38, 
wherein  the  management  of  asthma  patients 
is  described  and  discussed  in  a  very  orga- 
nized manner. 

The  major  disappointments  are  Chapters 
58  and  59.  First,  it  seems  a  little  odd  that 
chapters  on  occupational  and  physical  ther- 
apy are  put  in  the  part  dealing  with  psycho- 
social considerations.  Being  short,  they  are 
obviously  oriented  to  the  therapist  reader 
and  are  no  doubt  meant  to  be  very  practical. 
This  would  be  the  case  if  they  were  suitably 
written  and  gave  an  acceptable  number  of 
references.  Unfortunately,  this  is  not  the  case 
here,  the  occupational  therapy  chapter  be- 
ing only  3  pages  in  length  and  giving  only 
7  references.  The  physical  therapy  chapter 
is  no  less  disappoinfing,  particularly  the 
paragraph  on  respiratory  muscle  strength 
and  endurance  training  (P.  686).  This  topic 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1495 


Book,  Films,  Tapes,  &  Software 


is  discussed  in  other  ciiapters  in  a  scientific 
manner,  one  chapter  (42)  being  entitled 
"Ventilatory  Muscle  Training".  And  then 
suddenly  in  Chapter  59.  the  "author's  own 
experience"  (P.  686)  becomes  the  valuable 
tool  to  evaluate  the  usefulness  of  this  ther- 
apy (P.  686).  This  is  definitely  not  in  line 
with  the  rest  of  the  book. 

The  last,  but  not  least,  part  of  the  book. 
Part  7,  is  entitled  "Art  and  Rehabilitation" 
and  gives  both  the  physician's  and  patient's 
points  of  view.  This  lifts  our  scientific  think- 
ing perhaps  onto  another  plane,  reminding 
us  of  the  philosophic  aspect  of  science,  med- 
icine, and  caregiving.  In  our  times,  which 
are  marked  by  highly  specialized  technol- 
ogy, it  is  fully  reasonable  to  keep  this  in 
mind. 

In  general,  in  spite  of  the  above-men- 
tioned annoying  shortcomings,  this  book  can 
be  highly  recommended  for  all  participants 
— not  only  physicians,  but  also  other  pro- 
fessionals, such  as  therapists,  nurses,  psy- 
chologists, and  physiologists  — and  students 
in  the  rehabilitation  of  patients  with  respi- 
ratory diseases. 

Marta  Gudjonsdottir  MD 
Ciaudio  F  Donner  MD 

Salvatore  Maugeri  Foundation 

Division  of  Pulmonary  Disease 

Rehabilitation  Institute  of  Veruno 

Veruno,  Italy 

REFERENCES 

1.  Hodgkins  JE.  Petty  TL.  Chronic  obstruc- 
tive pulmonary  tlLsease;  current  concepts. 
Philadelphia:  WB  Saunders,  1987. 

2.  Casaburi  R,  Petty  TL.  Principles  and  prac- 
tice of  pulmonary  rehabilitation.  Philadel- 
phia: WB  Saunders,  1993. 

SI  Units  for  Clinical  Measurement. 

Donald  S  Young  MB  PhD  and  Edward  J 
Huth  MD,  with  additional  contributors.  Phil- 
adelphia: American  College  of  Physicians. 
1998.  Soft-cover,  331  pages,  $36.00. 

The  United  States  is  the  only  major  coun- 
try in  the  world  that  has  not  completely  com- 
mitted to  the  use  of  the  metric  system.  Amer- 
ican medicine  has  adopted  the  metric  system 
for  some  uses  but  has  lagged  behind  the  rest 
of  the  medical  world  in  adopting  the  Sy  steme 
international  d' unites  (the  International  Sys- 
tem of  Units,  abbreviated  SI).  This  book  is 
intended  for  American  clinicians  needing 


guidance  in  the  proper  use  of  SI  units  in 
their  practices  and  publications.  It  is  essen- 
tially a  collection  of  reference  data  with  some 
explanatory  text. 

The  book  is  organized  into  the  following 
chapters  (all  with  references): 

1.  The  Metric  System  and  Its  Develop- 
ment into  The  International  System  of  Units. 
Brief  (8-page)  history  of  the  metric  system 
from  the  first  publication  in  1585  on  the 
advantages  of  a  decimal  system  (by  a  dike 
inspector  from  the  Netherlands),  through  the 
French  Revolution,  to  current  United  States 
policy. 

2.  SI  Units,  Base  and  Derived;  Additional 
Accepted  Units:  and  Style  Rules.  Six-page 
chapter  with  tables  on  base  units  of  the  SI, 
prefixes  and  symbols,  and  style  specifica- 
tions for  publication. 

3.  Units  for  Medical  Practice.  Two-page 
chapter  on  using  SI  units  for  mass  (weight), 
heights,  and  length. 

4.  Special  Units,  Older  Metric  Unit.';,  SI 
Units,  Conversion  Factors,  and  Values  in 
Healthy  Persons.  This  chapter  is  composed 
of  sections  (with  separate  references)  dedi- 
cated to  the  specific  practices  of  audiology, 
cardiovascular  medicine,  laboratory  medi- 
cine, nephrology,  nutrition,  pharmacology, 
pulmonary  medicine,  and  radiology.  The 
section  on  pulmonary  medicine  was  co- 
written  by  Arthur  Slutsky .  a  well-known  pul- 
monary researcher.  This  section  contains 
comprehensive  lists  of  terms,  symbols,  com- 
ments, older  metric  units,  SI  units,  conver- 
sion factors,  and  (rough)  reference  values 
for  pulmonary  medicine  and  respiratory 
physiology.  The  tables  include  values  for 
pulmonary  mechanics,  gas  exchange,  and 
hemodynamics. 

5.  Introducing  SI  Units  to  the  Hospital. 
This  chapter  is  interesting  in  that  it  presents 
a  15-step  procedure  and  timeline  for  suc- 
cessful conversion  to  SI  units  within  a  hos- 
pital. This  procedure  is  inodeled  after  one 
used  in  Canada.  The  authors  note  that  "the 
changeover  was  not  a  difficult  experience, 
and  the  fear  of  the  change  was  greater  than 
the  reality."  True  for  most  things  in  life. 

The  remaining  274  pages  of  the  book  are 
divided  into  3  appendixes: 

Appendix  I .  Chemical  Analytes  and  He- 
matologic Measurements:  Units,  Conver- 
sion Factors,  Significant  Digits,  and  Sug- 
gested Increments. 

Appendix  2.  Index  of  Synonyms  for  Ana- 
lytes and  Cross  References  to  Entry  Terms 
of  Appendix  I. 


Appendix  3.  Amounts  of  Administered 
Constituents  in  One  Liter  of  Solution. 

This  book  is  well  organized  and  provides 
enough  background  data  to  put  the  subject 
into  proper  context.  Being  a  reference  text 
compo.sed  mostly  of  laboratory  values,  it 
may  have  limited  appeal  to  respiratory  ther- 
apists who  are  not  routinely  involved  in  re- 
search. Also,  the  normal  or  reference  values 
presented  in  the  text  are  intended  to  provide 
a  general  guide  to  the  magnitude  of  the  test 
values  reported  in  SI  units  and  should  not 
be  used  for  clinical  interpretations  in  pa- 
tients. 

Robert  L  Chatbum  RRT  FAARC 

Respiratory  Care  Department 

University  Hospitals  of  Cleveland 

Department  of  Pediatrics 

Case  Western  Reserve  University 

Cleveland,  Ohio 

Publishing  Your  Medical  Research  Pa- 
per: What  They  Don't  Teach  in  Medical 
School.  Daniel  W  Byrne.  Philadelphia;  Lip- 
pincott  Williams  &  Wilkins.  1998.  Soft- 
cover,  288  pages,  $23.95. 

Research  papers  submitted  to  Respira- 
tory Care  and  other  health  care-related  sci- 
ence journals  come  mainly  from  people 
without  formal  training  in  study  design,  re- 
search methods,  or  scientific  writing.  Al- 
though medical  schools  and  clinical  train- 
ing programs  are  beginning  to  acknowledge 
the  need  for  this  kind  of  training,  most 
would-be  authors  have  simply  followed  the 
examples  of  their  colleagues  and  of  pub- 
lished articles  in  a  kind  of  trial-and-error 
apprenticeship.  Some  with  a  natural  gift  for 
organization  and  written  communication 
take  to  the  process  fairly  readily,  but  for 
most  it  can  be  difficult,  unpleasant,  and  dis- 
couraging. In  the  absence  of  previous  u-ain- 
ing,  investigator-authors  could  benefit  a 
great  deal  from  a  user-friendly  yet  authori- 
tative resource  for  planning,  doing,  and  suc- 
cessfully publishing  a  research  study.  Here 
is  just  such  a  resource. 

Trained  originally  in  biostatistics,  the  au- 
thor is  a  free-lance  consultant  to  medical 
researchers  and  authors.  Although  it  is  not 
explicitly  stated,  the  book  is  targeted  at  med- 
ical students,  and  its  goal  is  "to  explain  how 
to  anticipate  and  avoid  the  problems  typi- 
cally encountered  in  designing  a  research 
study  and  writing  a  publishable  paper."  The 


149(1 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Book,  Films,  Tapes,  &  Software 


title  is  thus  a  bit  misleading  in  that  the  work 
addresses  the  whole  process  of  biomedical 
research  rather  than  just  writing  papers.  In 
addition,  the  book  should  be  equally  valu- 
able to  beginning  clinical  investigators  at 
any  level  and  in  any  category,  not  just  med- 
ical students. 

Material  in  the  book  comes  not  only  from 
Byrne's  extensive  experience  in  consulting 
on  (and,  obviously,  teaching)  the  subject 
matter,  but  also  from  actual  manuscript  re- 
views and  from  a  quasi-research  study  he 
conducted  in  its  preparation.  As  stated  in 
the  preface,  the  author  surveyed  "a  number 
of  experts,  including  editors-in-chief  of 
prominent  medical  journals,  peer  reviewers 
for  the  Journal  of  the  American  Medical 
Association,  and  recent  Nobel  Prize  win- 
ners," for  their  experiences  and  opinions. 
Throughout  the  book  he  provides  figures, 
tables,  quotes,  and  statistics  based  on  the 
results  of  the  survey  to  make  or  illustrate 
specific  points. 

The  book  is  divided  into  5  sections,  34 
chapters,  5  appendixes,  a  bibliography,  and 
an  index.  Most  chapters  are  quite  short 
— many  only  one  or  two  pages.  There  are 
42  figures  and  67  tables  altogether.  The  text 
is  further  broken  up  by  highlighted  boxes, 
bullet  points  marked  with  a  variety  of  icon- 
like symbols  denoting  "vital  points,"  quotes 
from  actual  reviews,  and  the  like,  giving  the 
whole  a  telegraphic,  "executive  summary" 
appearance  that  moves  it  along  quickly,  not 
lingering  on  any  single  topic. 

Section  1  (planning)  includes  chapters  on 
types  of  clinical  study,  how  to  construct  a 
data  collection  form,  and  overviews  on  end 
points,  outcomes,  and  sample  sizes.  These 
and  other  discussions  in  this  section  alert 
the  reader  to  the  importance  of  the  topics 
addressed,  although  they  may  not  provide 
sufficient  detail  to  enable  the  first-time  in- 
vestigator to  actually  deal  with  them.  The 
chapter  on  "preparing  to  write  a  publishable 
paper"  should  strike  a  chord  for  any  journal 
editor  or  editorial  board  member.  It  con- 
tains valuable  information  on  selecting  the 
right  target  journal  — something  that  should 
be  done  before  starting  to  write  the  paper 
— and  admonishes  authors  to  read  and  fol- 
low that  joumafs  instructions  for  authors. 
Would  that  more  of  them  did  so!  Also  in- 
cluded in  this  chapter  are  instructions  to  sub- 
mit a  manuscript  that  is  shorter  than  the 
target  journal's  average,  and  to  avoid  doing 
things  that  irritate  reviewers  (eg,  "simplify 
busy  tables")  and  editors  (eg,  "eliminate  re- 
dundancy"). As  a  reality  check  for  authors. 


this  chapter  also  contains  a  table  listing  typ- 
ical acceptance  rates  for  unsolicited  manu- 
scripts received  by  various  journals;  for  the 
New  England  Journal  of  Medicine  it  is  7%. 

Section  2  (observing)  contains  chapters 
on  collecting  and  interpreting  data.  Although 
not  really  comprehensive  enough  to  enable 
the  reader  to  carry  out  the  procedures  inde- 
pendently, the  chapters  on  univariate  and 
multivariate  analysis,  nonparametric  tests, 
and  matching  provide  a  good  feel  for  what 
these  statistical  methods  do  and  when  they 
should  be  used. 

The  third  section  (writing)  is  the  book's 
most  extensive  and,  in  my  opinion,  its  stron- 
gest. A  chapter  on  choosing  the  right  title 
contains  a  helpful  guide  to  the  important 
elements  of  a  good  title  and  a  list  of  words 
and  phrases  to  avoid.  Readers  are  advised 
to  keep  abstracts  short,  specific,  and  con- 
sistent with  the  body  of  the  paper.  The  "meth- 
ods" chapter,  appropriately  one  of  the  long- 
est in  the  book,  seeks  to  help  the  reader 
avoid  rejection  of  the  paper  because  of  in- 
adequate explanation  of  what  was  done.  Ex- 
tensive guidance  is  provided  on  effective 
presentation  of  study  results,  and  the  dis- 
cussions on  when  to  use  tables  and  figures 
are  thorough  and  helpful.  According  to  the 
chapter  on  the  discussion  section,  this  should 
almost  always  be  shortened  and  more  atten- 
tion paid  to  the  study's  shortcomings.  The 
chapter  on  references  includes  helpful  ex- 
amples for  citing  statistical  software  and 
other  nontraditional  sources. 

Sections  4  (editing)  and  5  (revising)  could 
well  have  been  combined,  although  this 
would  have  prevented  the  author  from  mak- 
ing the  acronym  POWER  from  the  first  let- 
ters of  the  sections  and  using  this  as  a  uni- 
fying vehicle  throughout  the  book.  There  is 
much  helpful  advice  here,  such  as  to  seek 
internal  peer  review  prior  to  submission,  and 
a  form  for  this  purpose  is  included.  Tables 
list  colloquialisms,  cliches,  and  euphemisms 
to  avoid,  along  with  26  ways  not  to  start  a 
sentence  (eg,  "It  has  been  shown  . . .").  Il- 
lustrative examples  of  correct  or  preferred 
usage  are  provided,  such  as  when  to  use 
"that"  versus  "which."  The  chapter  on  re- 
sponding to  reviewers'  comments  once  the 
paper  has  been  through  the  initial  phase  of 
peer  review  is  insightful  and  practical.  For 
dealing  with  galleys  and  page  proofs,  tradi- 
tional proofreader's  shorthand  marks  are 
listed  and  identified  in  a  table.  Byrne  ends 
his  text  with  a  list  of  7  "ideal  papers"  — ci- 


tations to  published  articles  that  he  feels 
come  closest  to  fulfilling  the  requirements 
set  forth  in  the  book. 

There  are  5  appendixes,  which  by  and 
large  are  well  chosen  and  helpful.  The  peer 
review  questionnaire  used  by  the  author  in 
his  "research  study"  of  editor  and  reviewer 
opinions  is  reproduced  in  its  entirety.  A 
4-page  data  collection  form  from  a  trauma 
demographics  study  is  provided  as  an  ex- 
ample of  a  well  thought-out  clinical  data 
collection  tool.  The  largest  appendix  is  a 
34-page  "medical  researcher's  directory" 
consisting  of  an  annotated  listing  of  re- 
sources for  clinical  investigator-authors. 
Though  it  is  hard  to  imagine  the  practical 
value  of  some  of  these  listings  (such  as  news- 
papers, a  mail  order  office  supply  company, 
and  The  White  House),  a  lot  of  them — such 
as  professional  societies,  governmental  and 
other  potential  grant  sources,  publishers,  and 
a  variety  of  indexes,  most  with  web  sites  or 
E-mail  addresses — should  be  helpful  to  the 
reader. 

The  author  imparts  considerable  wisdom 
in  the  pages  of  this  book,  making  it  a  very 
worthwhile  contribution  to  the  modest  lit- 
erature in  this  field.  The  quotes  from  editors 
and  reviewers  expand  and  illuminate 
Byrne's  points,  although  the  sources  of  these 
are  never  identified.  Prominently,  the  text 
draws  on  the  results  of  the  author's  survey 
of  editors,  reviewers,  and  unspecified  oth- 
ers, and  here  I  think  he  should  be  chided 
just  a  bit  for  not  practicing  what  he  preaches 
with  respect  to  presenting  methods  and  re- 
sults. Throughout  the  book,  information 
from  this  "study"  is  provided  in  the  form  of 
bar  graphs  and  rank-order  lists,  many  pre- 
sented as  quantitative  data.  Yet  nowhere  is 
it  stated  who  the  survey  recipients  were, 
how  they  were  selected,  or,  importantly, 
how  many  of  those  approached  actually 
filled  out  the  1 2-page,  34-item  questionnaire. 
Many  figures  and  tables  show  the  numbers 
of  responses,  but  denominators  are  not  pro- 
vided, and  it  is  unknown  whether  the  re- 
sponse rate  reached  the  60%  threshold  often 
accepted  as  a  minimum  for  validity  of  sur- 
vey data. 

Maybe  this  criticism  is  irrelevant  for  what 
is  essentially  a  book  of  collected  wisdom 
and  advice  about  planning  and  writing  up  a 
good  research  project.  Also  probably  irrel- 
evant is  my  mild  distaste  for  the  book's 
physical  appearance  and  presentation  style, 
which  is  a  sort  of  cross  between  USA  Today 


Respiratory  Care  •  December  1999  Vol  44  No  12 


149" 


Book,  Films,  Tapes,  &  Software 


and  an  Internet  Web  site.  This  format  gives 
the  impression  that  the  intended  audience- 
was  judged  unable  to  digest  information  in- 
gested in  bites  more  substantial  than  dental- 
soft  "factoids"  and  other  small,  pureed 
swallows. 

Despite  these  quibbles,  the  fact  is  that 
this  is  a  very  good  book.  On  my  recommen- 
dation, my  division's  fellowship  training 


program  has  purchased  copies  for  each  of 
its  ttainees,  and  I  hope  they  all  use  it.  As  a 
researcher  I  will  need  more  comprehensive 
sources  on  study  design,  especially  for  sta- 
tistics, than  provided  here.  As  an  author, 
however,  I  will  use  it;  as  a  mentor  I  am 
already  finding  it  useful;  as  a  manuscript 
reviewer  I  will  retain  a  number  of  its  pearls; 
and  as  an  editor  I  wish  that  everyone  who 


submits  a  manuscript  to  Respiratory  Care 
will  have  read  it  — before  they  started. 

David  J  Pierson  MD 

Division  of  Pulmonary  and 

Critical  Care  Medicine 

University  of  Washington 

Editor  in  Chief 

Respiratory  Care 

Seattle,  Washington 


^ 

^ 


#^ 


^^^^jftwMicanfcjf,/^.^ 


RE/PI 


% 


%> 


^«'/. 


fOj 


'% 


% 


QVRE 


# 


<?? 


/ 
#• 


1498 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Open  Forum  Abstracts 


ACCURACY   OF  PULSE  OXIMKTERS   DURING  NEONATAL 
MOTION.  Ricardo  Liberman  MD.  Michael  Holmes  BS.  RRT.  Ray  Taschuk 
CRTT.  Ixirilee  Snclling  BSN,  RN.  Neonatal  Dcpt.  Huntingion  Memorial 
Hosp.  Pasadena.  CA 

Background:  Pulse  oximetry  has  been  used  for  over  a  dectide  in  the  NICU  as  an  indicator  of 
pulse  rate  (PR)  and  oxygen  satuiaiion  (SpO,)  of  arterial  blood.  However,  the  validity  of  PR 
and  SpOj  readings  arc  often  suspect  during  motion.  Masimo  ShT  pulse  oximeffy  (Masimo 
Corp.  Irvine.  CA)  claims  to  measure  during  motion  conditions  as  well  as  low  perfusion. 
Nellcor  Puritan  Bennett  (Pleasamon,  CA)  makes  a  similar  claim  with  Oxisman  technology 
(e.g..  N  295)  but  not  with  their  N-2(X)  pulse  oximeters.  Methods:  Sensors  from  a  Masimo 
HFV  and  a  N.29.S  pulse  oximeter  were  attached  to  opposing  feel  of  an  infant,  whose  feet  were 
secured  to  a  motion  generator.  The  motion  genciator  provided  neonatal  movcilKnt  and  was 
configured  to  simulate  a  kicking  infant  in  frequency  and  ampliiude.  An  additional  pulse 
oximeter  (N-200)  was  attached  to  the  infant's  right  hand,  which  served  as  a  stationary- 
reference  site  (i.e..  not  exposed  to  the  motion  geneiator).  Data  (FCG  hean  rate,  PR  and  SpOi) 
were  aillected  every  second  ( I  Hz)  by  a  computerized  data  acquisition  (DAQ)  system.  A  blood 
specimen  (ABO)  was  drawn  after  30  to  120  seconds  of  motion.  The  ABO  draw  lime  was 
noted  in  the  DAQ  file.  ITie  sensors  were  switched  between  feet  and  anodler  ABO  obtained 
after  30  - 1 20  seconds  of  applied  motion.  An  A VL  OMNI  (AVI.  Ijst  GmbH  Medizinlechnik. 
Oraz,  Austria)  was  used  for  ABO  analysis  uf  pH,  PCC),.  PO,.  lolal  Mb,  *COHb.  %MetHb. 
and  functional  %SaO;.  The  bias  and  precision  of  PR  versus  the  KCG  monitor  heart  rate  and 
SpO.  versus  functional  ISaO;  were  calculated.  Resalts:  122  ABO  and  DAQ  samples  were 
analyzed  from  14  newborns:  gestation  of  22  -  40  weeks  and  weight  of  495  -  4100  gms.  Ten 
zero  outs  (SpO:  display  of  0  9)  and  one  outlier  >  65!  were  excluded  from  the  calculations  [N- 
295  (8),  N.200  (2).  and  Masimo  (1)].  The  heart  late  (via  ECO  raoniux)  ranged  from  83  to 
200  bpm.  The  ranges  of  ABO  values  were:  pH  of  7.20  to  7.55,  PCO,  of  22.0  to  63.6 
mraHg,  PO:  of  44.4  to  111.6  mmHg.  total  Hb  of  9.4  to  17.3.  COHbof  0.0to4.2  », 
MetHb  of  0.8  to  2.m,  ml  SaO,  of  82.7  to  95.8  %. 


Oxiitieter 

PR  IMasI 
(pitcision) 

SpO,  Ibiasj 
(precision) 

Masimo 
SET 

-0.1     (±  3.0) 

-0.9    (±  2.3) 

N-295 

-3.4    (±  18.0) 

+5.1     (±8.1) 

N-200 

+5.2    (±20.9) 

+0.3    (±4,6) 

Discussion:  Most  pulse  oximeter  manufacturers  state  a  precision  for  pulse  rate  of  ±  3  bpm 
and  a  precision  for  SpO:  of  ±  3  %  (at  a  bias  of  0)  in  neonates  during  non-motion  conditions. 
However,  motion  is  common  in  this  population.  Conclusions:  Motion  adversely  affects 
most  pulse  oximeters  and  spurious  values  can  lead  to  inappropriate  care.  Conventional  pulse 
oximeters,  including  Oxismart,  performed  much  worse  dian  their  published  accuracy 
specification  in  this  study.  Masimo  SKI  pulse  oximeuy  reflected  SaO,  and  FX:G  hean  rate 
accurately  during  motion  and  broad  use  should  improve  care, 

OF-99-162 


Ventilator  Management  by  Respiratory  Therapists  (RTs) 
during  a  M ulticenter  Randomized  Trial  of  Non-Invasive 
Proportional  Assist  Ventilation  (PAV)  VS.  Pressure  Support 
Ventilation  (PSV)  in  Acute  Respiratory  Failure  (ARF)  Pts. 
P  Gay  MD,  S  Holets  RRT.  CCRA.  D  Hcs-s  PhD,  D  Nelson  RRT, 
N  Hill  MD.  Mayo  Clinic-Rochester,  MN;  Mass  Gen  Hosp- 
Boston,  MA;  Rhode  Island  Hosp-Providcnce,  Rl 
Background:  We  have  reported  that  PAV  and  PSV  modes  rcsuhcd  in 
similar  intubation  rates  and  mortality  in  pts  with  ARF  (Am  J  Resp  Crit 
Care  1999;  159:A14).  We  wished  to  test  wheUier  excessive  effort  by 
RTs  was  needed  and  provided  to  patients  for  the  PAV  vs  PSV  mode. 
Methods:  Pts  with  ARF  were  randomized  to  receive  PAV  or  PSV  mode 
and  we  prospectively  charted  both  the  number  of  times  pts  needed 
encouragement  (#ENC)  to  continue  and  how  many  inspiratory  ventilator 
setting  changes  (#IPAP)  were  required  for  optimizing  each  mode. 
Results:  There  was  a  significantly  higher  %pts  encouraged  (p  <  0.02) 
and  more  total  pt  encours^ement  episodes  (p  <  0.04)  for  PSV  mode 


(Mean  +  SD  %Pts-PSV  vs  PAV=  44  ±  10  vs  22  +  13;  Total  #ENC-PSV 
vs  PAV=  19.5  +  15.2  vs  7.5  +  6.2).  There  was  no  significant  difference 
(p  >  0,15)  in  the  #IPAP  changes  between  the  2  modes  (#IPAP-PSV  vs 
PAV-2,8  +  1.9  vs  5.5  +  3,1).  The  #ENC  for  the  first  6  hours  is  shown, 
CoBclusioiu:  PAV  mode  required  similar  ventilator  sening  changes  and 
less  pt  encouragement  effort  than  PSV  mode  in  this  clinical  trial. 
Study  hindcd  by  Rcspironics  Idc.  Murraysville,  PA. 

OF-99-104 


CORRECTION  TO  OPEN  FORUM  ABSTRACTS 

Due  to  technical  difficulties,  the  two  abstracts  above  were  not  printed  in  full  in 
the  October  issue  of  the  Journal  and  thus  are  reprinted  here.  [Respir  Care 
1999;44(10):1243,  1256] 


We  regret  the  error. 


Respiratory  Care  •  December  1999  Vol  44  No  12 


149' 


Appreciation  of  Reviewers 


The  Editors  of  RESPIRATORY  Care  are  deeply  grateful  to  the  following 
persons  who  have  contributed  their  expertise  and  time  to  the  reviewing 
of  manuscripts  and  Open  Forum  abstracts  during  the  past  year. 


Alexander  B  Adams  MPH  RRT 
Lindarose  Allaway  RRT 
Michael  Anders  RRT 
Dennis  Archer  RRT 
Jeanette  Asselin  MS  RRT 
Michael  J  Banner  PhD  RRT 
Alan  F  Barker  MD 
Thomas  A  Barnes  EdD  RRT 
Ralph  E  Bartel  MEd  RRT 
William  J  Beach  MBA  RRT 
Christopher  D  Beaty  MD 
D  E  Bebout  PhD  RRT 
Joshua  O  Benditt  MD 
Kathleen  M  Beney  MS  RRT 
Maureen  Best 
Peter  Betit  RRT 
Luca  M  Bigatello  MD 
Frank  E  Biondo  RRT 
Forrest  M  Bird  MD  PhD  ScD 
Craig  Patrick  Black  PhD  RRT 
Griffith  M  Blackmon  MD 
Susan  Blonshine  RPFT  RRT 
David  Bowton  MD 
Thomas  Brack  MD 
Richard  D  Branson  RRT 
Matthew  Brenner  MD 
Laurent  J  Brochard  MD 
Robert  A  Brown  RPFT  RRT 
Robert  S  Campbell  RRT 
Christopher  M  Cella  RRT 
Bartolome  R  Celli  MD 
David  W  Chang  EdD  RRT 
Richard  Channick  MD 
Robert  L  Chatburn  RRT  FAARC 
Andrew  R  Clark  PhD 
Michelle  Cloutier  MD 
Steven  A  Conrad  MD 
Marie  B  Coyle  PhD 
W  Hal  Cragun  MD 
Ken  C  Craig  RRT 


Gerard  J  Criner  MD 

Deborah  L  Cullen  EdD  RRT 

Bruce  H  Culver  MD 

Robert  Czachowski  PhD 

Michael  P  Czervinske  RRT 

Richard  N  Dalby  PhD 

Randy  De  Kler  MS 

Steven  A  Deem  MD 

Edgar  Delgado  RRT 

Rajiv  Dhand  MD 

William  H  Dubbs  MHA  RRT 

Patrick  J  Dunne  MEd  RRT  FAARC 

Charles  G  Durbin  Jr  MD 

Thomas  D  East  PhD 

Kevin  P  Fennelly  MD 

Warren  H  Finlay  PhD 

Richard  M  Ford  RRT  RCP 

Sam  P  Giordano  MBA  RRT 

J  David  Godwin  MD 

Richard  B  Goodman  MD 

Michael  K  Gould  MD 

Wesley  M  Granger  PhD  RRT 

John  M  Graybeal  CRTT 

Carl  F  Haas  MLS  RRT 

Neil  B  Hampson  MD 

Ken  Hargett  RRT 

John  E  Heffner  MD 

Dean  R  Hess  PhD  RRT  FAARC 

Mark  J  Heulitt  MD 

Nicholas  S  Hill  MD 

Robert  Himle  MS  RRT 

John  E  Hodgkin  MD 

Lee  Hoffman  MD 

Leslie  A  Hoffman  PhD  RN 

John  Hotchkiss  MD 

James  M  Hurst  MD 

Charles  G  Irvin  PhD 

Jiunn-Song  Jiang  MD 

Jay  A  Johannigman  MD 

Robert  M  Kacmarek  PhD  RRT 


Thomas  J  Kallstrom  RRT 

Lucy  Kester  MBA  RRT 

Max  Kirmse  MD 

Marin  H  Kollef  MD 

Helen  R  Kotilainen 

Janet  Larson  PhD 

Franfois  Lemaire  MD 

David  M  Lewinsohn  MD  PhD 

Frederic  Lofaso  MD 

Neil  R  Maclntyre  MD 

Nicholas  J  Macmillan  AGS  RRT 

Patricia  Maher  RN  CGRN 

Patricia  Maher  RN  CGRN 

Barry  Make  MD 

Cynthia  Malinowski  MA  RRT 

Jorge  Mancebo  MD 

Harold  Manning  MD 

Kimberly  Marquis  MD 

Susan  L  Mclnturff  RCP  RRT 

Warren  C  Miller  MD 

Shelley  C  Mishoe  PhD  RRT  FAARC 

Jolyon  P  Mitchell  PhD  FRSC  C  Chem 

Joseph  Morfei  MS  RRT 

Carl  D  Mottram  RRT  RPFT 

Timothy  R  Myers  RRT 

George  Nakos  MD 

Stefano  Nava  MD 

Michael  T  Newhouse  MD 

Jon  O  Nilsestuen  PhD  RRT  FAARC 

Walter  J  O'Donohue  Jr  MD 

Frederick  P  Ognibene  MD 

Grant  O'KeefeMD 

Timothy  B  Op't  Holt  EdD  RRT 

Marcy  F  Petrini  PhD 

Robert  Pettignano  MD 

Thomas  L  Petty  MD 

Fran  Piedalue  RRT 

Susan  P  Pilbeam  MS  RRT 

Michael  R  Pinsky  MD 

Michael  W  Prewitt  PhD  RRT 


150u 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Appreciation  of  Reviewers 


Joseph  L  Rau  PhD  RRT 
Ray  Ritz  RRT 
Julien  M  Roy  RRT 
Gordon  D  Rubenfeld  MD 
Gregg  L  Ruppel  MEd  RRT  RPFT 
John  S  Sabo  MS  RRT 
John  W  Salyer  RRT 
Robert  E  Sandblom  MD 
Rodney  A  Schmidt  MD 
Theresa  Ryan  Schultz  CPFT  RRT 

CRT 
Marvin  I  Schwarz  MD 
Om  P  Sharma  MD 
D  Michael  Shasby  MD 
John  W  Shigeoka  MD 


John  M  Shneerson  MA  DM 

Mark  D  Siegel  MD 

Mark  Simmons  MSEd  RPFT  RRT 

Michael  W  Sipes  RRT 

Shawn  J  Skerrett  MD 

Joseph  Spahn  MD 

Charles  B  Spearman  RRT 

Kenneth  P  Steinberg  MD 

David  A  Stempel  D 

Eric  J  Stem  MD 

Karen  J  Stewart  RRT 

Thomas  E  Stewart  MD 

James  K  Stoller  MD 

Charlie  Strange  MD 

Celeste  R  Stubbs  RRT 

Eric  R  Swenson  MD 


Robert  D  Tarver  MD 
Rozanna  Templin  CCPT 
William  Thompson  MD 
John  E  Thompson  RRT 
Brian  L  Tiep  MD 
Jeffrey  S  Vender  MD 
Rennet  M  Wang  MD 
Jack  Wanger  MBA  RRT  RPFT 
Jeffrey  J  Ward  MEd  RRT 
Robert  R  Weilacher  RRT 
Barbara  G  Wilson  MEd  RRT 
Linda  Wilson  RRT 
Theodore  J  Witek  DrPH  RPFT 
Everett  T  Wood  MS  RRT 
Irwin  Ziment  MD 
Richard  L  ZuWallack  MD 


Respiratory  Care  Open  Forum  2000 

Respiratory  Care  welcomes  abstracts  of  scientific  reports  on  any  aspect  of  respiratory 
care  presented  as 

•  an  original  study 

•  the  evaluation  of  a  method,  device,  or  protocol 

•  a  case  or  case  series 

If  your  abstract  is  accepted  for  publication  in  Respiratory  Care,  you  will  be  invited  to 
present  it  at  the  46th  International  Respiratory  Congress  in  Cincinnati,  Ohio. 

See  the  Call  for  Abstracts  2000  in  this  issue  for  more  information. 

Early  deadline:  February  29,  2000 


Respiratory  Care  •  December  1999  Vol  44  No  12 


1501 


Author  Index  to  Volume  44  (1999) 


Aboussouan  LS:  An  82-year-old  man  with  amyotrophic 
lateral  sclerosis,  44(10):1203  PFT  nuggets 

Aboussouan  LS:  A  7 1  -year-old  man  with  progressive  short- 
ness of  breath  and  orthopnea,  44(12):1491  PFT  nuggets 

Adams  AB,  coauthor:  Bliss  PL  44(8):925,  coauthor:  Ta- 
kahashi  T  44(8):918 

Afari  N,  coauthor:  Schmaling  KB  44(12):  1452 

Ahmad  M,  coauthor:  Kathawalla  S  44(4):443,  coauthor: 
Kathawalla  S  44(8)  :959 

Aitken  ML:  Cystic  fibrosis  in  adults,  44(3):368  books, 
films,  tapes,  &  software 

Ambrosino  N,  coauthor:  Clini  E  44(1):29,  coauthor:  Clini 
E  44(4):415 

Anderson  WC:  A  medical  myth,  44(10):1209  letter 

Aranda  M  &  Pearl  RG:  The  biology  of  nitric  oxide,  44(2): 
156  conference  proceedings 

Au  D:  Introductory  medical  statistics,  3rd  ed,  44(7):869 
books,  films,  tapes,  &  software 

Axton  KL  Jr:  Basic  ECG  interpretation,  44(9):1139  books, 
films,  tapes,  &  software 


B 


Bacha  EA:  Perioperative  use  of  inhaled  nitric  oxide  for 
heart  and  lung  transplantation,  44(2):205  conference  pro- 
ceedings 

Bamhart  S,  coauthor:  Schmaling  KB  44(12):1452 

Basile  J:  Laboratory  exercises  for  competency  in  respira- 
tory care,  44(1):82  books,  fdms,  tapes,  &  software 

Bateman  ST,  coauthor:  Thompson  J  44(2):177 

Baum  VC,  coauthor:  Rich  OF  44(2):  196 

Becker  EA  &  Gibson  CC:  Attitudes  among  practicing  re- 
spiratory therapists  in  a  midwestem  state  toward  com- 
pleting a  baccalaureate  degree  and  toward  distance  ed- 
ucation, 44(11):1337  research  article 


Beckett  RG:  Professional  ethics:  a  guide  for  rehabilitation 
professionals,  44(7):867  books,  films,  tapes,  &  software 
Benditt  JO:  Essentials  of  cardiopulmonary  exercise  test- 
ing, 44(1):81  books,  films,  tapes,  &  software 
Betit  P,  coauthor:  Thompson  J  44(2):  177 
Bhorade  SM,  coauthor:  Hinkes  E  44(5):524 
Bianchi  L,  coauthor:  Clini  E  44(4):415 
Bidani  A,  coauthor:  Duarte  AG  44(10):1207 
Bigatello  LM:  Strategies  to  enhance  the  efficacy  of  nitric 

oxide  therapy,  44(3):331  conference  proceedings 
Binder  A,  coauthor:  Konschak  MR  44(5):506 
Binder  RE,  coauthor:  Konschak  MR  44(5):506 
Bishop  MJ:  Who  should  perform  intubation?,  44(7):750 

conference  proceedings 
Blanch  LL:  Acute  respiratory  distress  syndrome:  cellular 
and  molecular  mechanisms  and  clinical  management, 
44(5)  :535  books,  fdms,  tapes,  &  software 
Blanch  PB:  Mechanical  ventilator  malfunctions:  a  descrip- 
tive and  comparative  study  of  6  common  ventilator 
brands,  44(10):1183  research  article 
Bliss  PL,  coauthor:  Takahashi  T  44(8):918 
Bliss  PL  et  al:  A  bench  study  comparison  of  demand  ox- 
ygen delivery  systems  and  continuous  flow  oxygen, 
44(8):925  research  article 
Blonshine  S,  coauthor:  Carella  MJ  44(12):1458 
Boehm  R  &  Kennedy  D:  Conquering  childhood  asthma: 
an  illustrated  guide  to  understanding  and  control  of  child- 
hood asthma,  44(10):  1213  books,  films,  tapes,  &  soft- 
ware 
Boyle  K:  Self-management  of  asthma,  44(2):225  books, 

films,  tapes,  &  software 
Branson  RD,  coauthor:  Durbin  CG  Jr  44(6):593 
Branson  RD:  Humidification  for  patients  with  artificial 

airways,  44(6):630  conference  proceedings 
Branson  RD:  Response  to  Gilman,  44(11):1388  letter 
Branson  RD  et  al:  Comparison  of  conventional  heated 
humidification  with  a  new  active  hygroscopic  heat  and 


150: 


Respiratory  Care  •  December  99  Vol  44  No  12 


Author  Index  to  Volume  44  (1999) 


moisture  exchanger  in  mechanically  ventilated  patients, 

44(8):912  research  article 
Branson  RD  et  al:  Inhaled  nitric  oxide:  delivery  systems 

and  monitoring,  44(3):281  conference  proceedings 
Buchwald  DS,  coauthor:  Schmaling  KB  44(12):  1452 
Bugedo  G,  coauthor:  Takahashi  T  44(8):9I8 


Cairo  JM:  Interpretation  of  pulmonary  function  tests:  a 
practical  guide,  44(12):1494  books,  films,  tapes,  &  soft- 
ware 

Campbell  RS,  coauthor:  Branson  RD  44(3):281,  coau- 
thor: Branson  RD  44(8):912 

Campbell  RS:  Extubation  and  the  consequences  of  reintu- 
bation,  44(7):799  conference  proceedings 

Caras  WE  et  al:  Performance  comparison  of  the  hand-held 
MicroPlus  portable  spirometer  and  the  SensorMedics 
Vmax22  diagnostic  spirometer,  44(12):1465  research 
article 

Carella  MJ  et  al:  Improvement  in  pulmonary  and  exercise 
performance  in  obese  patients  after  weight  loss,  44(12): 
1458  research  article 

Cascade  FN,  coauthor:  Kazerooni  EA  44(9):  1033  reviews, 
overviews,  &  updates 

Chang  J:  Symj5/oSys  PFT  pulmonary  function  test,  44(6): 
702  books,  fdms,  tapes,  &  software 

Channick  RN,  coauthor:  Yung  GL,  44(10):1210 

Channick  RN  &  Yung  GL:  Long-term  use  of  inhaled  nitric 
oxide  for  pulmonary  hypertension,  44(2):212  confer- 
ence proceedings 

Chatburn  RL:  Health  devices  sourcebook  1999:  medical 
product  purchasing  directory  with  offical  universal  med- 
ical device  nomenclature  system,  44(11):1391  books, 
films,  tapes,  &  software.  Healthcare  standards  1999  of- 
ficial directory,  44(11):  1391  books,  films,  tapes  &  soft- 
ware 

Chatburn  RL:  SI  units  for  clinical  measurement,  44(12): 
1496  books,  films,  tapes,  &  software 

Clini  E  et  al:  Dependence  nursing  scale:  a  new  method  to 
assess  the  effect  of  nursing  work  load  in  a  respiratory 
intermediate  intensive  care  unit,  44(1):29  research  ar- 
ticle 

Clini  E  et  al:  Long-term  tracheostomy  in  severe  COPD 
patients  weaned  from  mechanical  ventilation,  44(4):415 
research  article 

Collins  J:  Chest  imaging  in  the  trauma  intensive  care  unit, 
44(9):  1044  reviews,  overviews,  &  updates 

D 

Davis  K  Jr,  coauthor:  Branson  RD  44(8):912 
Davis  TA  &  Mathewson  HS:  Opioids  and  respiratory  de- 
pression, 44(1):78  drug  capsule 


De  Kler  RM,  coauthor:  Waugh  JB  44(5):520 

Delgado  E  et  al:  Continuous  and  expiratory  tracheal  gas 
insufflation  produce  equal  levels  of  total  PEEP,  44(4): 
428  research  article 

Demers  B:  Role  of  bicarbonate  ion  concentration  in  acid- 
base  balance,  44(8):963  letter 

Dhand  R,  coauthor:  Fink  JB  44(1):24,  coauthor:  Fink  JB 
44(1):53,  coauthor:  Fink  JB  44(11):1353 

Dhand  R  &  Fink  JB:  Dry  powder  inhalers,  44(8):940  re- 
views, overviews,  &  updates 

Dillard  TA:  Can  we  rehabilitate  the  chest  wall?,  44(4):407 
editorial 

Dillard  TA,  coauthor:  Caras  WE  44(12):1465 

Donner  CF,  coauthor:  Gudjonsdottir  M  44(12):  1495 

Doorley  PA  &  Durbin  CG  Jr:  Thoracic  imaging  in  the 
intensive  care  unit:  improving  clinical  skills  and  access 
means  better  patient  care,  44(9):  1015  editorial 

Duarte  AG  et  al:  Capnography  in  a  double-lung  transplant 
recipient  with  respiratory  failure,  44(10):  1207  graphics 
corner 

Durbin  CG  Jr,  coauthor:  Doorley  PA  44(9):  1015,  coau- 
thor: Jaeger  JM  44(6):661 

Durbin  CG  Jr:  Respiratory  therapists  and  conscious  seda- 
tion, 44(8):909  editorial 

Durbin  CG  Jr  &  Branson  RD:  Foreword:  artificial  air- 
ways— the  1998  Respiratory  Care  journal  conference, 
44(6):593  conference  proceedings 

Durmowicz  AG:  Pediatric  asthma,  44(11):  1390  books, 
films,  tapes,  &  software 

Dwyer  TM,  coauthor:  Patel  RG  44(4):421 


E 


Eckert  B:  Vital  capacity  maneuver  in  modified  spirometry 

technique,  44(12):  1493  letter 
Emad  A:  A  60-year-old  woman  with  dyspnea  on  exertion, 

44(4)  :437  test  your  radiologic  skill 


Fink  JB,  coauthor:  Dhand  R  44(8):940 

Fink  JB  &  Dhand  R:  Technology  at  the  bedside:  Aerosol 
therapy  in  respiratory  care,  44(1):24  editorial 

Fink  JB  &  Dhand  R:  Bronchodilator  resuscitation  in  the 
emergency  department.  Part  I  of  2:  device  selection, 
44(11):1353  reviews,  overviews,  &  updates 

Fink  JB  et  al:  Bronchodilator  therapy  in  mechanically  ven- 
tilated patients,  44(1):53  reviews,  overx'iews,  &  updates 

Fluck  RR  Jr:  Manual  of  pulmonary  function  testing,  7th 
ed,  44(8):965  books,  films,  tapes,  &  software 

Foss  SA  &  Keppel  JW:  In  vitro  testing  of  MDI  spacers:  a 
technique  for  measuring  respirable  dose  output  with  ac- 


Respiratory  Care  •  December  99  Vol  44  No  12 


150' 


Author  Index  to  Volume  44  (1999) 


tuation  in-phase  or  out-of-phase  with  inhalation,  44(12): 
1474  research  article 
Frame  S,  coauthor:  Branson  RD  44(8):912 


Gera  CM,  coauthor:  Carella  MJ  44(12):  1458 

Gerlach  H,  coauthor:  Gerlach  M  44(2):  184,  coauthor: 
Gerlach  M  44(3)  :349 

Gerlach  M  et  al:  Inhaled  nitric  oxide  for  acute  respiratory 
distress  syndrome,  44(2):184  conference  proceedings 

Gerlach  M  &  Gerlach  H:  Exhaled  nitric  oxide,  44(3):349 
conference  proceedings 

Gibson  CC,  coauthor:  Becker  EA  44(11):1337 

Gilman  G:  Humidification  for  patients  with  artificial  air- 
ways: more  on  the  HME  booster,  44(11):1388  letter 

Gladwin  MT:  Cardiopulmonary  critical  care,  3rd  ed,  44(6): 
704  books,  films,  tapes,  &  software 

Goldberg  S:  Contagion  and  confinement:  controlling  tu- 
berculosis along  the  skid  road,  44(11):1392  books,  fdms, 
tapes,  &  software 

Goss  CH:  Pulmonary  pathophysiology — the  essentials, 
44(2):222  books,  films,  tapes,  &  software 

Gossain  VV,  coauthor:  Carella  MJ  44(12):  1458 

Grissom  CK:  High  life:  a  history  of  high-altitude  physiol- 
ogy and  medicine,  44(8):968  books,  films,  tapes,  &  soft- 
ware 

Gross  GW:  Chest  imaging  in  the  neonatal  and  pediatric 
intensive  care  units,  44(9):  1095  reviews,  overviews,  & 
updates 

Gudjonsdottir  M  &  Donner  CF:  Rehabilitation  of  the  pa- 
tient with  respiratory  disease,  44(12):1495  books,  fdms, 
tapes,  &  software 


H 


Hashimoto  S,  coauthor:  Hayashi  S  44(11):1375 

Hayashi  S  et  al:  Diffuse  panbronchiolitis:  poor  recognition 
outside  Asia  and  implications  of  treatment  with  eryth- 
romycin, 44(11):1375  special  article 

Haynes  JM:  Diffusing  capacity  and  the  vasodilatory  re- 
sponse to  INO,  44(10):1210  letter 

Haynes  JM:  Lung  protective  ventilatory  strategies  for 
ARDS,  44(4):445  letter 

Head  CA:  Effects  of  inhaled  nitric  oxide  on  blood  ele- 
ments: a  novel  therapy  for  sickle  cell  disease,  44(3):340 
conference  proceedings 

Heffner  JE:  Artificial  airways:  conference  summary,  44(7): 
861  conference  proceedings 

Heffner  JE:  Tracheotomy:  indications  and  timing,  44(7): 
807  conference  proceedings 

Helmholz  HF  Jr:  Bicarbonate,  oh,  bicarbonate,  44(8):952 
special  article 


Helmholz  HF  Jr:  Understanding  acid-base,  44(8):965 
books,  fdms,  tapes,  &  software 

Helms  M,  coauthor:  Maclntyre  NR  44(12):1447 

Henig  NR:  UpToDate  in  pulmonary  disease  and  critical 
care  medicine,  44(2):223  books,  films,  tapes,  &  soft- 
ware 

Henry  DA:  Chest  imaging  in  the  neurosciences  intensive 
care  unit,  44(9):  1064  reviews,  overviews,  &  updates 

Hess  DR,  coauthor:  Branson  RD  44(3):281 

Hess  DR:  Adverse  effects  and  toxicity  of  inhaled  nitric 
oxide,  44(3):315  conference  proceedings 

Hess  DR:  Design  of  pulse  oximeters,  44(4):448  books, 
films,  tapes,  &  software 

Hess  DR:  Indications  for  translaryngeal  intubation,  44(6): 
604  conference  proceedings 

Hess  DR:  Managing  the  artificial  airway,  44(7):759  con- 
ference proceedings 

Hess  DR  &  Hurford  WE:  Foreword:  inhaled  nitric  oxide — 
the  1998  Respiratory  Care  journal  conference,  44(2): 
155  conference  proceedings 

Hillier  S:  Methods  in  pulmonary  research,  44(1):81  books, 
films,  tapes,  &  software 

Hinkes  E  et  al:  Young  adult  with  near-fatal  pneumonia 
caused  by  adenovirus  serotype  7,  44(5):524  case  report 

Hoberty  PD  &  Hoberty  R:  Guidelines  for  pulmonary  re- 
habilitation programs,  44(3):367  books,  films,  tapes,  & 
software 

Hoberty  R,  coauthor:  Hoberty  PD  44(3):367 

Hoffman  LA,  coauthor:  Delgado  E  44(4):428 

Holets  S:  Mechanical  ventilation  manual,  44(4):447  books, 
films,  tapes,  &  software 

Homma  I,  coauthor:  Kakizaki  F  44(4):409 

Horie  T,  coauthor:  Hayashi  S  44(11):1375 

Hughes  JM:  Mosby's  CPG  mentor:  patient  cases  in  respi- 
ratory care:  aerosol  therapy,  44(5):535  books,  films, 
tapes,  &  software 

Hunton  DA  &  Kaminsky  DA:  Flow-volume  loop  analysis 
of  airflow  limitation:  "all  that  obstructs  is  not  bronchial 
asthma,"  44(8):955  PFT  corner 

Hurford  WE,  coauthor:  Hess  DR  44(2):  155 

Hurford  WE:  Conference  summary:  is  inhaled  nitric  oxide 
therapeutic?,  44(3):360  conference  proceedings 

Hurford  WE:  Nasotracheal  intubation,  44(6):643  confer- 
ence proceedings 

Hurford  WE:  Orotracheal  intubation  outside  the  operating 
room:  anatomic  considerations  and  techniques,  44(6): 
615  conference  proceedings 

Hyde  K,  coauthor:  Maunder  RJ  44(12):  1494 


Jaeger  JM  &  Durbin  CG  Jr:  Special  purpose  endotracheal 
tubes,  44(6):661  conference  proceedings 


150^ 


Respiratory  Care  •  December  99  Vol  44  No  12 


Author  Index  to  Volume  44  (1999) 


Johannigman  JA,  coauthor:  Branson  RD  44(3):281,  coau- 
thor: Branson  RD  44(8):912 

Jones  M:  The  case  manager's  handbook,  2nd  ed,  coau- 
thor: Boehm  R  44(10):1213 


K 


Kakizaki  F  et  al:  Preliminary  report  on  the  effects  of  re- 
spiratory muscle  stretch  gymnastics  on  chest  wall  mo- 
bility in  patients  with  chronic  obstructive  pulmonary 
disease,  44(4):409  research  article 

Kaminsky  DA,  coauthor:  Hunton  DA  44(8):955 

Kapur  V:  Sleep  disorders  sourcebook,  44(7):866  books, 
films,  tapes,  &  software 

Kasper  CL:  Management  skills  for  the  new  health  care 
supervisor,  3rd  ed,  44(8):968  books,  films,  tapes,  &  soft- 
ware 

Kathawaila  S  &  Ahmad  M:  An  obese  patient  referred  for 
preoperative  pulmonary  clearance,  44(8)  :959  P FT  nug- 
gets 

Kathawaila  S  &  Ahmad  M:  A  patient  with  dyspnea  and 
acid  maltase  deficiency,  44(4)  :443  PFT  nuggets 

Kavuru  MS,  coauthor:  Mansharamani  N  44(1  ):76,  coau- 
thor: Rafanan  A  44(1):74 

Kavuru  MS  &  Stoiler  JK:  A  new  feature  for  the  journal: 
introducing  PFT  Nuggets,  44(1):73  PFT  nuggets 

Kazerooni  EA  &  Cascade  PN:  Chest  imaging  in  the  car- 
diac intensive  care  unit,  44(9):  1033  reviews,  overviews 
&  updates 

Keh  D,  coauthor:  Gerlach  M  44(2):  184 

Kennerly  D,  coauthor:  Boehm  R  44(10):  1213 

Keppei  JW,  coauthor:  Foss  SA  44(12):  1474 

Kester  L  &  Stoiler  JK:  Monitoring  quality  in  a  respiratory 
care  protocol  service:  methods  and  outcomes,  44(5):512 
research  article 

Khoo  MCK:  Advances  in  modeling  and  control  of  venti- 
lation, 44(11):1390  books,  films,  tapes,  &  software 

Klein  JS:  Chest  imaging  in  the  surgical  intensive  care  unit, 
44(9):  1078  reviews,  overviews,  &  updates 

Knebel  AR,  coauthor:  Leidy  NK  44(8):932 

Kollef  MH:  Therapist-directed  protocols:  their  time  has 
come,  44(5):495  editorial 

Konschak  MR  et  al:  Oxygen  therapy  utilization  in  a  com- 
munity hospital:  use  of  a  protocol  to  improve  oxygen 
administration  and  preserve  resources,  44(5):506  re- 
search article 

Kotagal  U,  coauthor:  Lied  MB  44(5):497 


Laskowski  D,  coauthor:  Stoiler  JK  44(4)  :441.  coauthor: 
Stoiler  JK  44(12):1493 

Leidy  NK  &  Knebel  AR:  Clinical  validation  of  the  func- 
tional performance  inventory  in  patients  with  chronic 


obstructive  pulmonary  disease,  44(8):932  research  ar- 
ticle 

Lewis  R:  Exam  review  and  study  guide  for  perinatal/pe- 
diatric  respiratory  care,  44(8):967  books,  films,  tapes,  & 
software 

Lick  S,  coauthor:  Duarte  AG  44(10):  1207 

Lierl  MB  et  al:  Trial  of  a  therapist-directed  protocol  for 
weaning  bronchodilator  therapy  in  children  with  status 
asthmaticus,  44(5):497  research  article 

Lowson  SM,  coauthor:  Rich  GF  44(2):  196 

Luchette  FA,  coauthor:  Branson  RD  44(8):912 


M 


Maclntyre  NR  et  al:  Automated  rotational  therapy  for  the 
prevention  of  respiratory  complications  during  mechan- 
ical ventilation,  44(12):  1447  research  article 

MacMahon  H:  Pitfalls  in  portable  chest  radiology,  44(9): 
1018  reviews,  overviews,  &  updates 

Mageto  Y:  One  minute  asthma:  what  you  need  to  know, 
4th  ed,  44(6):704  books,  films,  tapes,  &  software 

Mansharamani  N  &  Kavuru  MS:  A  56-year-old  smoker 
with  dyspnea,  44(1):76  PFT  nuggets 

Marini  JJ,  coauthor:  Takahashi  T  44(8):918 

Mathewson  HS,  coauthor:  Davis  TA  44(1):78 

Matute-Bello  G:  Human  immunodeficiency  virus  and  the 
lung,  44(4):449  books,  films,  tapes,  &  software 

Maunder  RJ  &  Hyde  K:  The  handbook  of  critical  care 
drug  therapy,  2nd  ed,  44(12):1494  books,  films,  tapes, 
&  sofpA'are 

McCarthy  K,  coauthor:  Stoiler  JK  44(4):441,  coauthor: 
Stoiler  JK  44(12):  1493 

McCarthy  K  &  Stoiler  JK:  Possible  underestimation  of 
shunt  fraction  in  the  hepatopulmonary  syndrome,  44(12): 
1486  special  article 

McCoy  RW,  coauthor:  Bliss  PL  44(8):925 

Mehta  AC,  coauthor  Seshadri  N  44(12):  1489 

Mendizabal  JE,  coauthor:  Morales  R  44(4):434 

Miller  WT  Jr:  Uses  of  thoracic  computed  tomography  in 
the  intensive  care  unit,  44(9):1127  reviews,  overviews, 
&  updates 

Minai  OA  &  Sullivan  EJ:  A  59-year-old  man  with  grad- 
ually increasing  dyspnea,  44(10):1205  PFT  nuggets 

Miro  AM,  coauthor:  Delgado  E  44(4):428 

Mishoe  SC:  Distance  education  in  respiratory  care:  whether 
we  want  it  or  not?,  44(11):1332  editorial 

Mitchell  JP  et  al:  Performance  of  large-volume  versus 
small-volume  holding  chambers  with  chlorofluorocar- 
bon-albuterol  and  hydrofluoroalkane-albuterol  sulfate, 
44(1  ):38  research  article 

Miyagawa  T,  coauthor:  Sullivan  JM,  44(1):22 

Morales  R  &  Mendizabal  JE:  Unrecognized  motor  neuron 
disease:  an  uncommon  cause  of  ventilator  dependency 
in  the  intensive  care  unit,  44(4):434  case  report 


Respiratory  Care  •  December  99  Vol  44  No  12 


1505 


Author  Index  to  Volume  44  (1999) 


Morfei  J:  Response  to  Demers,  44(8):963  letter 

Morfei  J:  Stewart's  strong  ion  difference  approach  to  acid- 
base  analysis,  44(1):45  reviews,  overviews,  &  updates 

Morton  DW:  Thoracic  radiology:  the  requisites,  44(9): 
1137  books,  films,  tapes,  &  software 

Moufarrej  R:  Principles  of  critical  care,  2nd  ed,  44(9): 
1137  books,  films,  tapes,  &  software 


N 


Nagel  MW,  coauthor:  Mitchell  JP  44(1):38 

Nanavaty  U:  The  ICU  book,  44(9):1138  books,  films,  tapes, 

&  software 
Ndukwu  IM,  coauthor:  Hinkes  E  44(5):524 


o 


Orens  D  &  Stoller  JK:  Implementing  a  respiratory  care 
protocol  service:  steps  and  impediments,  44(5):528  spe- 
cial article 

Orringer  MK:  The  effects  of  tracheostomy  tube  placement 
on  communication  and  swallowing,  44(7):845  confer- 
ence proceedings 

Ottaway  M,  coauthor:  Branson  RD  44(8):912 

Ozgun  EM  et  al:  The  impact  of  a  standardized  protocol  for 
placement  of  indwelling  arterial  catheters,  44(10):  1193 
research  article 


Patel  RG  et  al:  Work  of  breathing  during  weaning  from 

ventilation:  does  extending  weaning  with  continuous 

positive  airway  pressure  confer  any  advantage?,  44(4): 

421  research  article 
Patzwahl  LC:  Respiratory  care  pearls,  44(5):536  books, 

films,  tapes,  &  software 
Pearl  RG,  coauthor:  Aranda  M  44(2):156 
Petrini  MP,  coauthor:  Patel  RG  44(4):421 
Pettinichi  S,  coauthor:  Lierl  MB  44(5):497 
Pierson  DJ:  Publishing  your  medical  research  paper:  what 

they  don't  teach  in  medical  school,  44(12):1496  hooks, 

films,  tapes,  &  software 
Pinsky  MR,  coauthor:  Delgado  E  44(4):428 
Porta  R,  coauthor:  Clini  E  44(4):415 
Prewitt  MW:  Critical  thinking:  cases  in  respiratory  care, 

44(3):367  books,  films,  tapes,  &  software 
Punjabi  NM:  Analysis  of  failure  time  data:  an  introduction 

to  survival  analysis,  44(10):1198  special  article 


Rafanan  A  &  Kavuru  MS:  Borderline  normal?,  44(1):74 
PFT  nuggets 


Rau  JL,  coauthor:  Mitchell  JP  44(1):38 

Reasor  T,  coauthor:  Caras  WE  44(12):  1465 

Reibel  JF:  Decannulation:  how  and  where,  44(7):856  con- 
ference proceedings 

Reibel  JF:  Tracheotomy/tracheostomy,  44(7):820  confer- 
ence proceedings 

Reis  Miranda  D:  Quantitating  caregiver  work  load  in  the 
ICU:  the  therapeutic  intervention  scoring  system, 
44(1):70  special  article 

Rich  GF  et  al:  Inhaled  nitric  oxide  for  cardiac  disease, 
44(2):  196  conference  proceedings 

Ritz  R:  Methods  to  avoid  intubation,  44(6):686  conference 
proceedings 

Roberts  JD  Jr:  Inhaled  nitric  oxide  for  hypoxemic  respi- 
ratory failure  of  the  newborn,  44(2):  169  conference  pro- 
ceedings 

Robertson  HT:  Physiological  basis  of  ventilatory  support, 
44(4)  :446  books,  films,  tapes,  &  software 

Ropp  B,  coauthor:  Carella  MJ  44(12):  1458 

Roy  JM:  Pulmonary  rehabilitation  administration  and  pa- 
tient education  manual,  44(5):537  books,  films,  tapes,  & 
software 


Sahn  SA,  coauthor:  Maclntyre  NR  44(12):  1447 

Sailors  RM:  Medical  instrumentation:  application  design, 

44(1):83  books,  films,  tapes,  &  software 
Salyer  JW:  Response  to  Anderson,  44(10):1209  letter 
Sassoon  C:  Mechanical  ventialtion:  physiological  and  clin- 
ical applications,  3rd  edition,  44(7):866  books,  films, 
tapes,  &  software 
Schilz  RJ:  A  38-year-old  man  with  progressive  dyspnea 
and  a  clear  chest  roentgenogram,  44(8):961  PFT  nug- 
gets 
Schmaling  KB  et  al:  Medical  and  psychiatric  predictors  of 

airway  reactivity,  44(12):  1452  research  article 
Schmidt  G.  coauthor:  Maclntyre  NR  44(12):  1447 
Schoene  RB:  Sacred  space:  stories  from  a  life  in  medicine, 

44(3):366  books,  films,  tapes,  &  software 
Sebastian  KD,  coauthor:  Lierl  MB  44(5):497 
Seshadri  N  &  Mehta  AC:  A  66-year-old  woman  with  long- 
standing dyspnea  on  exertion,  44(12):1489  PFT  nuggets 
Shibuya  M,  coauthor:  Kakizaki  F  44(4):409 
Silvestri  GA,  coauthor:  Ozgun  EM  44(10):1193 
Sinclair  S:  Conquering  asthma:  an  illustrated  guide  to  un- 
derstanding and  care  for  adults,  2nd  ed,  44(10):1212 
books,  films,  tapes,  &  software 
Stanford  D:  The  survey  kit.  44(2):224  books,  films,  tapes, 

&  software 
Stauffer  JL:  Complications  of  endotracheal  intubation  and 
tracheotomy,  44(7):828  conference  proceedings 


1506 


Respiratory  Care  •  December  99  Vol  44  No  12 


Author  Index  to  Volume  44  (1999) 


Stern  EJ  &  Tarver  RD:  Foreword:  thoracic  imaging  in  the 

intensive  care  unit,  44(9):  1017  reviews,  overviews,  & 

updates 
Stewart  TE  &  Zhang  H:  Nitric  oxide  in  sepsis,  44(3):308 

conference  proceedings 
Stoller  JK,  coauthor:  Kavuru  MS  44(1):73,  coauthor: 

KefiterL44(5):5l2,  coauthor:  McCarthy  K  44(12):  1486, 

coauthor:  Orens  D  44(5):528.  coauthor:  Thaggard  I 

44(5):532 
Stoller  JK:  The  history  of  intubation,  tracheotomy,  and 

airway  appliances,  44(6):595  conference  proceedings 
Stoller  JK  et  al:  Measurements  of  FEV,  using  the  modi- 
fied spirometry  technique,  44(4):441  PFT  nuggets 
Stoller  JK  et  al:  Response  to  Haynes,  44(12):1493  letter 
Strange  C.  coauthor:  Ozgun  EM  44(10):1193 
Sullivan  EJ.  coauthor:  Minai  OA  44(10):  1205 
Sullivan  JM  &  Miyagawa  T:  Global  respiratory  care:  a 

case  of  common  interests,  not  common  credentials, 

44(1):22  editorial 
Susla  GM:  Respiratory  care  pharmacology,  5th  ed,  44(6): 

702  books,  films,  tapes,  &  software 
Suzuki  H,  coauthor:  Kakizaki  F  44(4):409 
Swenson  ER:  The  strong  ion  difference  approach:  can  a 

strong  case  be  made  for  its  use  in  acid-base  analysis?, 

44(1):26  editorial 


Thompson  J  et  al:  Pediatric  applications  of  inhaled  nitric 
oxide,  44(2):  177  conference  proceedings 

Tobin  MJ,  coauthor:  Fink  JB  44(1):53 

Tonelli  MR:  Withdrawing  mechanical  ventilation:  conflicts 
and  consensus,  44(11):  1383  special  article 


Vitacca  M,  coauthor:  Clini  E  44(1):29,  coauthor:  Clini  E 
44(4):415 


w 


Watson  CB:  Prediction  of  a  difficult  intubation:  methods 
for  successful  intubation,  44(7):777  conference  proceed- 
ings 
Waugh  JB  &  De  Kler  RM:  Inspiratory  time,  pressure  set- 
tings, and  site  of  supplemental  oxygen  insertion  affect 
delivered  oxygen  fraction  with  the  Quantum  PSV  non- 
invasive positive  pressure  ventilator,  44(5):520  research 
article 
Wilkins  RL:  Respiratory  care  anatomy  and  physiology: 
foundations  for  clinical  practice.  44(10):1212  books, 
films,  tapes,  &  software 
Winter  MG,  coauthor:  Caras  WE  44(12):1465 
Wood  LDH,  coauthor:  Hinkes  E  44(5):524 
Wunderink  R,  coauthor:  Maclntyre  NR  44(12):1447 


Takahashi  T  et  al:  Effects  of  tracheal  gas  insufflation  and 
tracheal  gas  exsufflation  on  intrinsic  positive  end-expi- 
ratory pressure  and  carbon  dioxide  elimination,  44(8): 
918  research  article 

Tarver  RD,  coauthor:  Stern  EJ  44(9):  1017 

Tasota  FJ,  coauthor:  Delgado  E  44(4):428 

Thaggard  I  &  Stoller  JK:  Practical  aspects  of  a  respiratory 
care  protocol  service:  staffing  and  training,  44(5):532 
special  article 

Thompson  AE:  Issues  in  airway  management  in  infants 
and  children,  44(6):650  conference  proceedings 


Yamada  M,  coauthor:  Kakizaki  F  44(4)  :409 
Yamazaki  T,  coauthor:  Kakizaki  F  44(4):409 
Yung  GL,  coauthor:  Channick  RN  44(2):212 
Yung  GL  &  Channick  RN:  Response  to  Haynes,  44(10): 
1210  letter 


Zhang  H,  coauthor:  Stewart  TE  44(3):308 


Respiratory  Care  •  December  99  Vol  44  No  12 


1507 


Subject  Index  to  Volume  44  (1999) 


1-128  JAN 
129-240  FEB 
241-384    MAR 


385-464  APR 
465-560  MAY 
561-720    JUN 


721-880  JUL 
881-992  AUG 
993-1152    SEP 


1153-1312  OCT 
1313-1408  NOV 
1409-1536    DEC 


Abstracts 

AARC  Open  Forum  1999,  1215 
Acid-base:  See  also  Arterial  blood  gases 
base  excess,  45 
bicarbonate  metabolism,  952 
book  reviews 

Understanding  acid-base,  965 
hyperproteinemia  in,  45 
strong  ion  difference,  45 
editorial,  26 
letter,  963 
whole  blood  buffer  base,  45 
Acid  maltase  deficiency 

dyspnea  in,  443 
Acidosis,  metabolic.  See  Metabolic  acidosis 
Activities  of  daily  living 

Functional  Performance  Inventory,  clinical  validation, 
932 
Acute  chest  syndrome 

in  sickle  cell  disease,  1118 
Acute  respiratory  distress  syndrome  (ARDS) 
book  reviews 

Acute  respiratory  distress  syndrome:  cellular  and  mo- 
lecular mechanisms   and   clinical   management, 
535 
chest  imaging,  in  cardiac  ICU,  1033 
inhaled  nitric  oxide  for,  331,  360 
clinical  trials,  184 
lack  of  response,  315 
pediatric,  177 
radiography,  1118 

response  to  lung  protective  ventilatory  strategies  (let- 
ter), 445 
Adenoviruses 

pneumonia  from,  case  report,  524 


Advance  directives 

mechanical  ventilation,  withdrawal  of, 
1383 
Aerosols  and  aerosol  administration:  See  also  Broncho- 
dilators,   bronchodilation   and   bronchodilator 

administration 

basic  concepts,  53 

bench  models,  mechanical  ventilation,  53 

dose  output  testing,  with  metered  dose  inhaler  spacers, 
in  vitro,  1474 

dry  powder  inhalers,  940 

factors  in  delivery,  940 

holding  chamber  capacity,  38  • 

Aerosol  therapy 

j3-agonist  weaning  in  pediatric  status  asthmaticus,  ther- 
apist-directed protocol,  497 

chlorofluorocarbon-albuterol  vs  hydrofluoroalkane- 
albuterol  sulfate,  38 

deposition  assessment  methods,  53 

device  selection,  in  emergency  department,  1353 

humidity  in,  53 

in  mechanical  ventilation,  53 

in  respiratory  care  (editorial),  24 

ventilator  circuit  characteristics,  53 
Afferent  nerves 

in  chest  wall,  408 
Airflow  obstruction 

flow-volume  loop  analysis  (PFT  Comer),  955 
Airway,  upper 

anatomy,  in  normal  adults,  615 

heat  and  moisture  exchange,  630 
Airway  injuries 

management  of,  650 
Airway  obstruction 

endotracheal  tube  resistance,  604 


1508 


Respiratory  Care  •  December  99  Vol  44  No  12 


Subject  Index  to  Volume  44  (1999) 


following  extubation,  in  children,  650 

as  tracheotomy  complication,  810,  839 
Airways,  artificial 

aspiration  protection,  604 

care  and  management,  indications,  604 

Combitube,  790 

complications,  807,  828 

conference  proceedings,  593,  750 

conference  summary,  861 

difficult  intubation,  777 

endotracheal  tubes,  special  purpose,  661 

esophageal  obturator,  790 

extubation 

criteria  for,  799 

failure,  801 

and  reintubation,  799 

history,  595 

humidification  for,  630 

in  infants  and  children 
complications,  650 
intubation  alternatives,  650 
management,  650 

intermediate,  790 

laryngeal  mask,  650,  790 

management  of,  759 

nasotracheal  intubation,  643 

outcomes  research,  863 

resource  allocation,  862 

risk  factors,  807 

supraglottal,  790 

technology  assessment,  864 

translaryngeal  intubation,  indications,  604 

transtracheal,  791 
Airways  reactivity:  See  also  Bronchial  provocation  testing 

medical  and  psychiatric  predictors,  1452 
Albuterol 

administration  and  dosage,  1355 
American  Association  for  Respiratory  Care  (AARC) 

global  respiratory  care  (editorial),  22 

Open  Forum  abstracts— 1999,  1215 
Amyotrophic  lateral  sclerosis  (ALS) 

in  elderly  man  (PFT  Nuggets),  1203 

progressive  shortness  of  breath  and  orthopnea  in  (PFT 
Nuggets),  1491 

in  ventilator  dependence,  case  report,  434 
Anatomy 

book  reviews 

Respiratory  care  anatomy  and  physiology:  founda- 
tions for  clinical  practice,  1212 

in  orotracheal  intubation,  615 
Anesthesia  and  anesthetics 

for  endotracheal  intubation,  615 
Anticoagulants 

and  difficult  intubation,  777 


Anxiety 

versus  asthma,  diagnostic  criteria,  1452 
Aorta 

injuries,  radiography,  1044 
ARDS.  See  Acute  respiratory  distress  syndrome  (ARDS) 
Arterial  blood  gases 

bicarbonate  regeneration,  952 

strong  ion  difference,  in  acid-base  analysis, 
26,  45,  963 
Artificial  airways.  See  Airways,  artificial 
Artificial  noses.  See  Heat  and  moisture  exchangers 
Aspiration 

airway  protection  from,  604 

amniotic  fluid,  imaging  in,  1 103 

as  intubation  complication,  828 

mechanical  (See  Suction  and  suctioning  devices) 

pneumonitis  from,  in  children,  1114 

as  tracheostomy  complication,  in  children,  851 
Assessment,  patient 

Functional  Performance  Inventory,  in  chronic  obstruc- 
tive pulmonary  disease,  932 

nursing  workload,  in  intermediate  ICU,  and  patient  de- 
pendency, 26 

respiratory  care  quality  monitoring,  512 

Asthma 

book  reviews 

Conquering  asthma:  an  illustrated  guide  to  under- 
standing and  care  for  adults,  2d  ed,  1212 
Conquering  childhood  asthma:  an  illustrated  guide 
to  understanding  and  control  of  childhood  asthma, 
1212 
One  minute  asthma:  what  you  need  to  know,  704 
Pediatric  asthma,  1390 
Self-management  of  asthma,  225 
bronchodilator  resuscitation,  in  emergency  department, 

1353 
care  flow  chart,  504 
in  children 

bronchodilator  weaning,  therapist-directed  protocol, 

497 
inhaled  nitric  oxide  in,  177 
flow-volume  loop  analysis  (PFT  Corner),  955 
helium-oxygen  gas  mixture  for,  692 
medical  and  psychiatric  predictors,  1452 
Atelectasis 

in  newborns,  radiography  for,  1 105 
in  portable  chest  radiography,  1031 
radiography,  in  pediatric  ICU,  1111 
during  suctioning,  759 
Attitude 

surveys,  distance  education,  1337 


I 


Respiratory  Care  •  December  99  Vol  44  No  12 


I50f' 


Subject  Index  to  Volume  44  (1999) 


Beds 

automated  rotating,  for  nosocomial  pneumonia  preven- 
tion, 1447 

rocking,  as  intubation  alternative,  686 
Bench  evaluations 

demand  oxygen  delivery  systems  vs  continuous  flow 
oxygen,  925 

MicroPlus  and  SensorMedics  portable  spirometers,  1465 

noninvasive  positive  pressure  ventilator,  520 
Bicarbonate,  sodium 

in  acid-base  balance,  45,  952,  963 

standards,  45 
Blood 

nitric  oxide  effects,  in  sickle  cell  disease  therapy,  340 
Blood  coagulation  disorders 

in  difficult  intubation,  777 
Biood  gases 

analyzers  and  supplies,  281 

arterial,  indications  for  indwelling  catheter  placement, 
1193 

monitoring 

end-tidal  carbon  dioxide,  615 
nitric  oxide,  281 

standard  bicarbonate  values,  45 
Book  reviews:  See  also  Software  reviews 

Acute  respiratory  distress  syndrome:  cellular  and  mo- 
lecular mechanisms  and  clinical  management,  535 

Advances  in  modeling  and  control  of  ventilation,  1 390 

Cardiopulmonary  critical  care,  3rd  ed,  704 

The  case  manager's  handbook,  2nd  ed,  1213 

Conquering  asthma:  an  illustrated  guide  to  understand- 
ing and  care  for  adults,  2d  ed,  1212 

Conquering  childhood  asthma:  an  illustrated  guide  to 
understanding  and  control  of  childhood  asthma,  1212 

Contagion  and  confinement:  controlling  tuberculosis 
along  the  Skid  Road,  1 392 

Critical  thinking:  cases  in  respiratory  care,  367 

Cystic  fibrosis  in  adults,  368 

Design  of  pulse  oximeters,  448 

Essentials  of  cardiopulmonaiy  exercise  testing,  81 

Exam  review  and  study  guide  for  perinatal/pediatric 
respiratory  care,  967 

Guidelines  for  pulmonary  rehabilitation  programs,  2nd 
ed,  367 

The  handbook  of  critical  care  drug  therapy,  2nd  ed, 
1494 

Health  devices  sourcebook  1999:  medical  product  pur- 
chasing directory  with  official  universal  medical  de- 
vice nomenclature  system,  1391 

Healthcare  standards  1999  official  directory,  1391 

High  life:  a  history  of  high-altitude  physiology  and  med- 
icine, 968 

Human  immunodeficiency  virus  and  the  lung,  449 

The  ICU  book,  1138 


Instructor' s  guide  to  critical  thinking:  cases  in  respira- 
tory care,  367 

Interpretation  of  pulmonary  function  tests:  a  practical 
guide,  1494 

Introductory  medical  statistics,  3rd  ed,  869 

Laboratory  exercises  for  competency  in  respiratory  care, 
82 

Management  skills  for  the  new  health  care  supervisor, 
3rd  ed,  968 

Manual  of  pulmonaiy  function  testing,  7th  ed,  965 

Mechanical  ventilation:  physiological  and  clinical  ap- 
plications, 3rd  ed,  866 

Mechanical  ventilation  manual,  441 

Medical  instrumentation:  application  and  design,  83 

Methods  in  pulmonary  research,  8 1 

One  minute  asthma:  what  you  need  to  know,  4th  ed,  704 

Pediatric  asthma,  1 390 

Physiological  basis  of  ventilatory  support,  446 

Principles  of  critical  care,  2nd  ed,  1 1 37 

Professional  ethics:  a  guide  for  rehabilitation  profes- 
sionals, 867 

Publishing  your  medical  research  paper:  what  they  don 't 
teach  in  medical  school,  1496 

Pulmonary  pathophysiology-the  essentials,  222 

Pulmonary  rehabilitation  administration  and  patient  ed- 
ucation manual,  537 

Rehabilitation  of  the  patient  with  respiratory  disease, 
1495 

Respiratory  care  anatomy  and  physiology:  foundations 
for  clinical  practice,  1212 

Respiratory  care  pearls,  536 

Respiratory  care  pharmacology,  5th  ed,  702 

Sacred  space:  stories  from  a  life  in  medicine,  366 

Self-management  of  asthma,  225 

SI  units  for  clinical  measurement,  1496 

Sleep  disorders  sourcebook,  866 

The  survey  kit,  224 

Thoracic  radiology:  the  requisites,  1137 

Understanding  acid-base,  965 
Breatliing,  work  of.  See  Work  of  breathing 
Bronchi 

rupture,  radiography,  1044 
Bronchial  provocation  testing:  See  also  Airways  reac- 
tivity 

in  asthma  diagnosis,  1452 
Bronchodilators,  bronchodilation,  and  bronchodilator 

administration:  See  also  Aerosols  and  aerosol  ad- 
ministration 

aerosol  therapy,  in  respiratory  care  (editorial),  24 

device  selection,  1353 

dosage,  53 

dyspnea  response,  76 

efficacy,  53 

in  emergency  department,  1353 


1510 


Respiratory  Care  •  December  99  Vol  44  No  12 


Subject  Index  to  Volume  44  (1999) 


in  mechanical  ventilation,  53 
guideline,  105 

weaning,  in  pediatric  status  asthmaticus,  therapist-di- 
rected protocol,  497 
Bronchoscopy 

history,  595 


Calcium  channel  blockers 

nitric  oxide  response  and,  212 
Capnography  and  capnometry 

in  bilateral  lung  transplant,  with  respiratory  failure,  1207 
Carbon  dioxide  (CO,) 

bicarbonate  regeneration,  952 

clearance,  in  tracheal  gas  insufflation  and  exsufflation, 
918 

end-tidal,  for  intubation  verification,  615 
Carbon  monoxide 

single-breath  carbon  monoxide  diffusing  capacity,  1999 
update 

guideline,  91;  guideline  amended,  539 
Cardiopulmonary  bypass 

in  heart  and  lung  transplantation,  205 
Cardiovascular  diseases  and  disorders 

book  reviews 

Cardiopulmonary  critical  care,  3rd  ed,  704 

radiography,  in  pediatric  ICU,  1122 
Cardiovascular  system 

chest  imaging,  in  cardiac  ICU,  1033 

inhaled  nitric  oxide  and,  196 
Case  management 

book  reviews 

The  case  manager's  handbook,  2nd  ed,  1212 
Case  reports 

adenoviral  pneumonia,  524 

motor  neuron  disease,  in  ventilator  dependence,  434 
Catheterization 

arterial,  indications  for,  1 193 

central  venous  and  heart,  in  chest  imaging,  1033 

complications,  in  neonatal  ICU  imaging,  1095 
Catheters,  arterial  and  venous 

protocols,  indwelling  arterial  catheter  placement,  1193 
Central  nervous  system 

nitric  oxide  in,  156 
Chemiluminescence 

nitric  oxide,  349 
Chest  imaging 

in  cardiac  ICU,  1033 

in  ICU 

editorial,  1015 

foreword  to  symposium,  1017 

in  neonatal  and  pediatric  ICUs,  1095 

in  neurosciences  ICU,  1064 

in  surgical  ICU,  1078 


in  trauma  ICU,  1044 
x-ray  vs  computed  tomography,  1 1 27 
Chest  injuries.  See  Thoracic  injuries 
Chest  wall 

abnormalities,  computed  tomography  for,  1132 
afferent  nerves,  408 
pulmonary  rehabilitation 

editorial,  407 

and  mobility,  409 
Chlorotluorocarbon  propellants 

holding  chamber  capacity,  in  aerosol  therapy,  38 
Chronic  lung  disease 

pediatric,  inhaled  nitric  oxide  in,  177 
Chronic  obstructive  pulmonary  disease  (COPD) 
acute  respiratory  failure,  415 

bronchodilator  resuscitation,  in  emergency  department,  1353 
chest  wall  rehabilitation,  409 

editorial,  407 
forced  expiratory  volume  measurement,  with  modified 

spirometry  (PFT  Nuggets),  441 
Functional  Performance  Inventory,  clinical  validation, 

932 
inhaled  nitric  oxide  for,  212,  315 
tracheostomy,  long-term,  following  mechanical  ventila- 
tion weaning,  415 
versus  diffuse  panbronchiolitis,  1375 
vital  capacity  maneuver  in  modified  spirometry  tech- 
nique (letter  and  response),  1493 
Chylothorax 

in  newborns,  1 105 
Clinical  practice  guidelines.  See  Guidelines,  recommen- 
dations, and  statements  and  Protocols 
Communication  disorders 

and  tracheostomy  tube  placement,  845 
Computed  tomography  (CT).  See  Tomography,  x-ray 

computed  (CT) 
Conference  proceedings 
artificial  airways,  593,  750 

complications,  828 

conference  summary,  861 

decannulation,  856 

difficult  intubation.  777 

extubation  and  reintubation,  799 

history,  595 

humidification,  630 

intubation,  methods  for  avoiding,  686 

management  of,  759 

nasotracheal  intubation,  643 

orotracheal  intubation,  615 

pediatric  management,  650 

special  purpose  endotracheal  tubes,  661 

tracheostomy  tube  placement,  845 

tracheotomy,  indications  for,  807 

tracheotomy  and  tracheostomy  techniques,  820 


Respiratory  Care  •  December  99  Vol  44  No  12 


151! 


Subject  Index  to  Volume  44  (1999) 


translaryngeal  intubation,  indications,  604 
inhaled  nitric  oxide,  155,  281 

for  acute  respiratory  distress  syndrome,  184 

adverse  effects  and  toxicity,  315 

biology,  156 

for  cardiac  disease,  196 

delivery  systems  and  monitoring,  281 

efficacy  enhancement,  331 

hypoxemic  respiratory  failure  of  newborns,  169 

pediatric  applications,  177 

perioperative,  for  heart  and  lung  transplantation, 

196 
for  pulmonary  hypertension,  212 
in  sepsis,  308 
for  sickle  cell  disease,  340 
summary,  360 
Continuing  education.  See  Education,  continuing 
Continuous  positive  airway  pressure  (CPAP):  See  also 
Positive  end-expiratory  pressure  (PEEP) 
for  bronchodilator  resuscitation,  1367 
as  intubation  alternative,  686 
in  mechanical  ventilation  weaning,  421 
COPD.  See  Clironic  obstructive  pulmonary  disease 

(COPD) 
Cost-effectiveness  and  cost  issues 
airway  management,  864 
bronchodilator  resuscitation  devices,  1371 
mechanical  ventilator  malfunctions,  1183 
oxygen  administration,  protocol,  506 
tracheotomy  vs  translaryngeal  intubation,  812 
Cricothyrostomy 

for  difficult  airway,  791 
Critical  care.  See  Intensive  care 
Critical  tliinking 
book  reviews 

Critical  thinking:  cases  in  respiratory  care,  367 
Instructor's  guide  to  Critical  thinking:  cases  in  re- 
spiratory care,  367 
Croup  (laryngotracheobronchitis).  See  Laryngeal  dis- 
eases and  disorders 
Cuffs,  tracheal  tube 
endobronchial,  661 
issues  related  to,  759 
Cystic  adenomatoid  malformation  of  lung 

congenital,  radiography  for,  1 108 
Cystic  fibrosis 
book  reviews 

Cystic  fibrosis  in  adults,  368 


Diagnosis 

dyspnea  on  exertion,  437 
Diaphragm 

congenital  hernia,  radiography  for,  1 1 07 


eventration,  437 
rupture,  radiography,  1044 
Diaphragmatic  pacing 

as  intubation  alternative.  686 
Difficult  airway.  See  Intubation,  difficult 
Diffusion  and  diffusion  testing 

single-breath  carbon  monoxide  diffusing  capacity,  1999 
update 

guideline,  91;  guideline  amended,  539 
Distance  education 

Distance  education  in  respiratory  care:  whether  we  want 

it  or  not?  (editorial),  1332 
respiratory  therapist  attitudes  toward,  1337 
Drowning  and  near-drowning 

radiography  for,  1114 
Drug  Capsule 

opioids  and  respiratory  depression,  78 
Drugs  and  drug  therapy 
book  reviews 

The  handbook  of  critical  care  drug  therapy,  2nd  ed, 

1494 
Respiratory  care  pharmacology,  5th  ed,  702 
Dry  powder  inhalers.  See  Nebulizers,  inhalers,  and  va- 
porizers 
Dyspnea  and  dyspnea  assessment 
in  acid  maltase  deficiency,  443 
bronchodilator  response,  76 
chest  wall  rehabilitation,  409 

editorial,  407 
in  chronic  obstructive  pulmonary  disease.  409 
with  clear  chest  roentgenogram  (PFT  Nuggets),  961 
on  exertion,  437 

longstanding  (PFT  Nuggets),  1489 
gradually  increasing  (PFT  Nuggets),  1205 
respiratory  muscle  stretch  gymnastics  in,  409 
in  smoker,  76 


ECG  interpretation 

Internet  reviews 

Basic  ECG  interpretation,  1 1 39 
ECMO.  See  Extracorporeal  membrane  oxygenation 

(ECMO) 
Edema 

cardiogenic,  radiography  of  1033 
Editorials 

Can  we  rehabilitate  the  chest  wall?,  407 

Distance  education  in  respiratory  care:  whether  we  want 

it  or  not?,  1 332 
Global  respiratory  care:  a  case  of  common  interests,  not 

common  credentials.  22 
Respiratory  therapists  and  conscious  sedation,  909 
The  strong  ion  difference  approach:  can  a  strong  case  be 

made  for  its  use  in  acid-base  analysis?,  26 


1512 


Respiratory  Care  •  December  99  Vol  44  No  12 


Subject  Index  to  Volume  44  (1999) 


Technology  at  the  bedside:  aerosol  therapy  in  respira- 
tory care,  24 
Therapist-directed  protocols:  their  time  has  come,  495 
Thoracic  imaging  in  the  intensive  care  unit:  improving 
clinical  siciiis  and  access  means  better  patient  care, 
1015 
Education,  continuing 
book  reviews 

Basic  ECG  interpretation,  1139 
CRCE  through  the  Journal- 1999,  970 
answer  key,  1311 
Education,  medical 

global  respiratory  care  (editorial),  22 
Education,  patient 
empowerment,  in  bronchodilator  therapy,  1369 
parent  education,  in  pediatric  tracheostomy,  845 
Education  and  training 

baccalaureate  degree,  respiratory  therapist  attitudes  to- 
ward, 1337 
book  reviews 

Laboratory  exercises  for  competency  in  respiratory 
Care,  82 
Distance  education  in  respiratory  care:  whether  we  want 
it  or  not?  (editorial),  1332 
Emergency  care 

bronchodilator  resuscitation,  device  selection,  1353 
orotracheal  intubation,  outside  emergency  room,  615 
Emphysema 

congenital  lobar,  radiography,  1108 
pulmonary  interstitial,  radiography,  1118 
subcutaneous,  radiography,  1119 
Endothelium 

and  inhaled  nitric  oxide,  340 
Endothelium  derived  relaxing  factor.  See  Nitric  oxide 
Endotracheal  tubes.  See  Tubes,  endotracheal 
End-tidal  CO,.  See  Carbon  dioxide  (COj),  end-tidal 
Enzymes 

nitric  oxide,  156 
Equipment  and  supplies 

automated  rotating  beds,  for  nosocomial  pneumonia  pre- 
vention, 1447 
book  reviews 

Health  devices  sourcebook  1999:  medical  product 
purchasing  directory  with  official  universal  medi- 
cal device  nomenclature  system,  1391 
bronchodilator  devices,  in  emergency  department,  1353 
inhaled  nitric  oxide  delivery  systems,  281 
mechanical  ventilator  malfunctions,  1183 
portable  spirometer  performance  comparison,  1465 
vascular  catheters  and  devices,  1033 
Esophageal  obturator  airway 

evolution  of,  790 
Esophagectomy 

postoperative  radiography,  1078 


Ethics,  professional 

book  reviews 

Professional  ethics:  a  guide  for  rehabilitation  profes- 
sionals, 867 
mechanical  ventilation,  withdrawal  of,  1383 
Evidence-based  medicine 

medical  myth  (letter  and  response),  1209 
Examinations  and  quizzes 
book  reviews 

Exam  review  and  study  guide  for  perinatal/pediatric 
respiratory  care,  967 
CRCE  through  the  journal— 1999,  970 
answer  key,  1311 
Exercise  testing 
book  reviews 

Essentials  of  cardiopulmonary  exercise  testing,  81 
Exertion 

dyspnea  on,  437,  1489 
Extracorporeal  membrane  oxygenation  (ECMO) 
for  persistent  pulmonary  hypertension,  in  newborn,  169 


Fiberoptic  instruments 

for  difficult  intubation,  788 
Flow  and  flowrate 

aerosol  dose  output  testing,  with  metered  dose  inhaler 
spacers,  in  vitro,  1474 
Flow-volume  curve 

loop  analysis,  airflow  limitation  (PFT  Comer),  955 

in  sleep  apnea  (PFT  Nuggets),  959 
Forced  expiratory  volume  (FEV) 

in  gradually  increasing  dyspnea  (PFT  Nuggets),  1205 

measurement,  with  modified  spirometry  (PFT  Nuggets), 
441 

vital  capacity  maneuver  in  modified  spirometry  tech- 
nique (letter  and  response),  1493 
Fraction  of  delivered  oxygen  (F„„^) 

variables,  in  noninvasive  positive  pressure  ventilator, 
520 
Fraction  of  inspired  oxygen  (F,„  ) 

in  acute  respiratory  distress  syndrome,  360 

in  inhaled  nitric  oxygen  delivery,  28 1 
Fractures 

of  thoracic  skeleton,  radiography,  1 122 
Functional  residual  capacity 

in  amyotrophic  lateral  sclerosis  (PFT  Nuggets),  1203 
Functional  status 

Functional  Performance  Inventory,  clinical  validation, 
932 
Futility 

mechanical  ventilation,  withdrawal  of,  1383 


Respiratory  Care  •  December  99  Vol  44  No  12 


1513 


Subject  Index  to  Volume  44  (1999) 


Gas  and  gases 

nitric  oxide,  manufacture  and  storage,  281 
Gastrointestinal  system 

nitric  oxide  in,  156 
Graft  preservation 

inhaled  nitric  oxide  for,  205 
Guanidine  monophosphate,  cyclic  (cGMP) 

in  nitric  oxide  metabolism,  156 
Guanylate  cyclase 

inhibitors,  308 
Guidelines,  recommendations  and  statements:  See  also 
Protocols 

aerosol  therapy,  in  respiratory  care  (editorial),  24 
for  intubation,  750,  863 
c  fCy-  removal  of  the  endotracheal  tube,  85 
<3-f&-  selection  of  device,  administration  of  bronchodilator, 
and  evaluation  of  response  to  therapy  in  mechanically 
ventilated  patients,  105 
CTf^  single-breath  carbon  monoxide  diffusing  capacity,  1999 

update,  91;  update  amended,  539 
CfCr  suctioning  of  the  patient  in  the  home.  99 
therapist-directed  (editorial),  495 
utilization  (editorial),  495 
Guillain-Barre  syndrome 

longstanding  dyspnea  on  exertion  (PFT  Nuggets), 
1489 


Head  and  neck  surgery 

endotracheal  tubes  for,  661 

Heart  catheterization  (Swan-Ganz).  See  Catheteriza- 
tion, central  venous  and  heart 

Heart  diseases 

inhaled  nitric  oxide  for,  196,  212,  360 

left  ventricular  dysfunction,  315 
Heart  failure 

in  children,  radiography,  1116 
Heart  injuries 

in  chest  trauma,  1044 
Heart  transplantation 

inhaled  nitric  oxide  for,  196,  205,  360 
Heat  and  moisture  exchangers:  See  also  HumidiHers 

and  humidiflcation 

active  hygroscopic,  630,  912 

for  ambulatory  patients,  630 

HME-Booster,  630 

Humidiflcation  for  patients  with  artificial  airways:  more 
on  the  HME  booster  (letter  and  response),  1388 

types  of.  630 
Helium-oxygen  gas  mixture 

for  asthma,  692 
Hemorrhage 

pulmonary,  neonatal,  imaging  in,  1 104 


Hepatopulmonary  syndrome 

shunt  fraction  underestimation  in.  1486 
Hernia,  diaphragmatic 

congenital,  radiography  for,  1 1 07 
High  altitude  physiology 

book  reviews 

High  life:  a  history  of  high-altitude  physiology  and 
medicine,  968 
History  of  respiratory  care  ; 

artificial  airways,  595 
Human  immunodeflciency  virus  (HIV) 

book  reviews 

Human  immunodeficiency  virus  and  the  lung.  449 
Human  leukocyte  antigen  (HLA) 

in  diffuse  panbronchiolitis,  1375 
Human  T-cell  leukemia  virus-l(HTLV-l) 

in  diffuse  panbronchiolitis,  1375 
Humidifiers  and  humidification:  See  also  Heat  and  mois- 
ture exchangers 

with  artificial  airways,  630 

artificial  noses,  630 

devices,  in  mechanical  ventilation,  630 

heated.  630,  912 
Hydrocarbons 

aspiration,  in  children,  radiography  for.  1115 
Hydrofluoroalkane  propellants 

holding  chamber  capacity,  in  aerosol  therapy,  38 
Hyperproteinemia 

in  acid-base  balance,  45 
Hypertension,  pulmonary.  See  Pulmonary  hypertension 
Hypoxemia  and  hypoxia 

inhaled  nitric  oxide,  and  pulmonary  hypertension,  212, 
315 

suction-related,  759 


Immature  lung  syndrome 

chest  imaging,  1 102 
Immune  disorders 

pulmonary  infection  in.  pediatric,  1114 
Infections  and  infection  control 
book  reviews 

Contagion  and  confinement:  controlling  tuberculosis 
along  the  Skid  Road,  1 392 
Inflammation  and  inflammatory  mediators 
nitric  oxide.  156.  308 
expired.  349 
Information  technology 

Distance  education  in  respiratory  care:  whether  we  want 
it  or  not?  (editorial).  1332 
Inhalation  devices.  See  Nebulizers,  inhalers,  and  vapor- 
izers 
Insufflation,  tracheal  gas 
continuous  vs  expiratory,  428 


1514 


Respiratory  Care  •  December  99  Vol  44  No  12 


Subject  Index  to  Volume  44  (1999) 


with  exsufflation,  918 
history,  595 

in  mechanical  ventilation.  428 
positive  end-expiratory  pressure,  428,  918 
Intensive  care 
book  reviews 

Principles  of  critical  care,  2nd  ed,  1137 
software  reviews 

UpToDate  in  pulmonary  and  critical  care  medicine, 
223 
Intensive  care  unit  (ICU) 
book  reviews 

The  ICU  hook,  1138 
nursing  work  load  assessment,  26,  70 
thoracic  computed  tomography  in,  1 1 27 
thoracic  imaging 

in  cardiac  ICU,  1033 

editorial,  1015 

foreword  to  special  issue,  1017 

in  neonatal  and  pediatric  ICUs,  1095 

in  neurosciences  ICU,  1064 

in  surgical  ICU,  1078 

in  trauma  ICU,  1044 
Intermittent  positive-pressure  breatliing  (IPPB) 

for  bronchodilator  resuscitation.  1367 
International  issues 

global  respiratory  care  (editorial),  22 
Internet 

Distance  education  in  respiratory  care:  whether  we  want 

it  or  not?  (editorial).  1332 
Website  reviews 

Basic  ECG  interpretation,  1 1 39 
Intracranial  pressure 

therapy,  in  neurogenic  pulmonary  edema,  1064 
Intubation 
bronchial,  759 
cuff-related  issues,  759 
difficult 

anatomic  problems,  777 

complications,  777 

direct  laryngoscopy  alternatives,  787 

fiberoptic  systems,  788 

laryngoscopy  options,  786 

prediction  and  scoring,  777 

transtracheal  airway,  791 
endotracheal  (See  also  Tubes,  endotracheal) 

aids  for,  661 

alternatives,  in  children,  650 

anesthesia  for,  615 

avoidance  of,  methods,  686 

awake.  615 

complications.  810,  828 

contraindications,  604 

for  croup,  650 


fiberoptic,  615 

in  head  and  neck  surgery,  661 

history,  595 

infection  from,  650 

intravenous  sedation,  615 

with  light  wand,  615 

lung  separation  techniques,  661 

removal  of  tube  (guideline),  85 

securing  tube,  759 

training  for,  750 

tube  position  assessment,  759 

unplanned  extubation,  833 

verification  of,  615 
esophageal,  759 
nasotracheal,  615,  643 
orotracheal.  615 
personnel  responsible  for.  750 
practice  guidelines,  750,  863 
secretion  clearance,  759 
stylets  for,  787 
translaryngeal 

complications,  807 

cost  factors,  812 

indications,  604 
Ischemia-reperfusion  injury 
endogenous  nitric  oxide  in,  349 


Laryngeal  diseases  and  disorders 

endotracheal  intubation  for,  650 

intubation  injuries,  828 
Laryngoscopy 

in  difficult  intubation,  777 

direct,  777 

fiberoptic,  615,  788 

history.  595 

options  for,  786 

for  orotracheal  intubation.  615 
Laryngotracheobronchitis  (Croup).  See  Laryngeal  dis- 
eases and  disorders 
Larynx 

anatomy,  615 
Letters  to  the  Editor 

Diffusing  capacity  and  vasodilatory  response  to  inhaled 
nitric  oxide.  1210 

Humidification  for  patients  with  artificial  airways:  more 
on  the  HME  booster,  1388 

Lung  protective  ventilatory  strategies  for  ARDS,  re- 
sponse. 445 

Medical  myth,  1209 

Medical  myth,  response.  1209 

Role  of  bicarbonate  ion  concentration  in  acid-base  bal- 
ance. 963 


Respiratory  Care  •  December  99  Vol  44  No  12 


151: 


Subject  Index  to  Volume  44  (1999) 


Vital  capacity  maneuver  in  modified  spirometry  tech- 
nique, 1493 
Vital  capacity  maneuver  in  modified  spirometry  tech- 
nique, response,  1493 
Leukocytes 

and  nitric  oxide,  340 
Life  support 

extracorporeal,  in  cardiac  ICU,  1033 
Liver  diseases,  ciironic 

hepatopulmonary  syndrome,  shunt  fraction  underesti- 
mation in,  1486 
Living  will 

mechanical  ventilation,  withdrawal  of,  1383 
L-NAME  (N'-nitro-L-arginine  methyl  ester) 

nitric  oxide  inhibition,  308 
Lung 

injuries,  radiography  for,  in  pediatric  ICU,  1120 

nitric  oxide  expression,  156 

parenchyma 

computed  tomography,  1 1 32 
radiography,  1044 
resection,  postoperative  radiography,  1078 
volume,  in  tracheal  gas  insufflation  and  exsufflation, 
918 
Lung  diseases 
book  reviews 

Pulmonary  pathophysiology-the  essentials,  222 
Rehabilitation  of  the  patient  with  respiratory  disease, 
1495 
Lung  transplantation 

capnography  in  bilateral  transplant,  with  respiratory  fail- 
ure, 1207 
cardiopulmonary  bypass  in,  205 
inhaled  nitric  oxide  for,  205,  360 


Managed  care 

book  reviews 

The  case  manager's  handbook,  2nd  ed, 
1212 
Management,  administrative 
book  reviews 

Management  skills  for  the  new  health  care  supervi- 
sor, 3rd  ed,  968 
Measurement  methods 
book  reviews 

SI  units  for  clinical  measurement,  1496 
Mechanical  ventilation 
aerosol  therapy,  53 
automated  rotational  therapy  in,  1447 
book  reviews 

Mechanical  ventilation:  physiological  and  clinical  ap- 
plications, 3rd  ed,  866 
Mechanical  ventilation  manual,  AAl 


Physiological  basis  of  ventilatory  support,  446 
bronchodilator  therapy,  53 

guideline,  105 
fraction  of  delivered  oxygen,  520 
history,  595 

humidification  in,  53,  630,  912 
indications,  604 

inhaled  nitric  oxide  delivery  systems,  281 
noninvasive  positive  pressure,  520,  604,  686 
tracheal  gas  insufflation  in,  428 
ventilator  circuit  characteristics,  53 
ventilator  malfunctions,  comparison  of  brands,  1 1 83 
weaning 

continuous  positive  airway  pressure,  421 
long-term  tracheostomy  following,  415 
pressure-support  ventilation,  421 
techniques,  800 
work  of  breathing,  42 1 
withdrawal  of,  ethics,  1383 
Meconium  aspiration  syndrome 

imaging  in,  1 103 
Mediastinum 

abnormalities,  computed  tomography  for,  1 1 32 
Medical  instrumentation 
book  reviews 

Medical  instrumentation:  application  and  design,  83 
Metabolic  acidosis 
measurement,  45 
strong  ion  difference,  45 
editorial,  26 
Metered  dose  inhalers  (MDI).  See  Nebulizers,  Inhalers, 

and  Vaporizers 
Methacholine 

inhalation  challenge,  in  asthma  diagnosis,  1452 
Methemoglobinemia 

and  inhaled  nitric  oxide,  360 
in  nitric  oxide  exposure,  315 
Metric  system 
book  reviews 

SI  units  for  clinical  measurement,  1496 
Mitral  valve 

surgery,  inhaled  nitric  oxide  for,  196 
Morbidity  and  mortality 

mechanical  ventilator  malfunctions,  1 192 
survival  analysis,  introduction,  1198 
Motor  neuron  disease 

ventilator  dependence  in,  case  report,  434 
Mouth 

anatomy,  615 


Nasopharynx 

anatomy,  615 
Nebulizers,  inhalers,  and  vaporizers 


1516 


Respiratory  Care  •  December  99  Vol  44  No  12 


Subject  Index  to  Volume  44  (1999) 


aerosol  therapy  (editorial),  24 

connection  to  ventilator  circuits,  53 

contamination,  53 

cost  factors,  1371 

dry  powder  inhalers,  940,  1 365 

holding  chamber  capacity,  38 

metered  dose  inhalers 

pressurized,  in  emergency  department,  1353 

spacers,  in  vitro  dose  output  testing,  1474 
staff  knowledge  of,  1370 
ultrasonic  nebulizers,  1364 
Negative  pressure  ventilation.  See  Ventilation,  negative 

pressure 
Neomuscularization,  169 
Neurologic  disorders 

and  cardiorespiratory  function,  1 064 
Neuromuscular  blockade 

for  endotracheal  intubation,  615 
Neuromuscular  disorders 
in  difficult  intubation,  777 
in  ventilator  dependence  (case  report),  434 
Nitric  oxide 

biology,  156,  166 

endogenous,  349 

enzymes,  156 

exhaled,  measurement  techniques,  349 

expression  in  lung,  156 

in  inflammation,  308 

inhaled 

in  acute  respiratory  distress  syndrome,  177,  184 

adverse  effects  and  toxicity,  184,  315,  360 

in  chronic  lung  disease,  177 

conference  proceedings,  155,  281 

delivery  systems,  212,  281 

diffusing  capacity  and  vasodilatory  response  (letter 
and  response),  1210 

dosage,  184 

for  heart  and  lung  transplantation,  205 

in  heart  disease,  196,  360 

hyporesponsiveness,  331 

for  hypoxemic  respiratory  failure  of  newborn,  169 

indications  for,  360 

monitoring,  281 

for  organ  transplantation,  360 

in  pediatric  asthma,  177 

for  pediatric  heart  surgery,  196 

and  positive  end-expiratory  pressure,  360 

for  pulmonary  hypertension,  long  term  use,  212 

pulmonary  vasodilation,  360 

for  sickle  cell  disease,  340 

therapeutic  use,  331,  360 
inhibitors,  308 

manufacture  and  storage,  281 
methemoglobinemia  from,  315 


pathophysiology,  349 

in  pulmonary  hypertension  pathogenesis,  212 

red  blood  cells  and,  340 

in  sepsis,  308 

transport,  184 
Nitrogen  dioxide 

from  inhaled  nitric  oxide  exposure,  315 

in  nitric  oxide  manufacture  and  storage,  281 
Nurses  and  nursing 

dependence  nursing  scale,  29 

ICU  work  load,  and  severity  of  illness,  29,  70 

Nine  Equivalents  of  Nursing  Manpower  Use  Score 
(NEMS),  70 

Therapeutic  Intervention  Scoring  System,  70 
Nutrition  and  malnutrition 

pediatric,  with  tracheostomy  tube,  851 


Obesity 

preoperative  pulmonary  clearance  (PFT  Nuggets),  959 

pulmonary  function  after  weight  loss,  1458 
Open  Forum 

abstracts— 1999,  1215 
Ophthalmologic  injuries 

in  difficult  intubation,  777 
Opioids 

and  respiratory  depression  (Drug  Capsule),  78 
Oral  surgery 

nasotracheal  intubation  for,  643 
Orthopnea 

progressive  shortness  of  breath  with  (PFT  Nuggets), 
1491 
Oximeters  and  oximetry 

book  reviews 

Design  of  pulse  oximeters,  448 
Oxygen  administration  and  therapy 

demand  systems  vs  continuous  flow,  925 

high-flow,  687 

laryngeal  mask  airways 
in  children,  650 
in  difficult  airway,  790 

noninvasive  positive  pressure  ventilator,  520 

protocols,  506 
Oxyhemoglobin 

nitric  oxide  binding,  340 


Pacemakers,  diaphragmatic.  See  Diaphragmatic  pac- 
ing 
Panbronchiolitis,  diffuse 

identification  and  treatment,  1 375 
Patent  ductus  arteriosus  (PDA) 

chest  imaging,  1102 
Patient  education.  See  Education,  patient 


Respiratory  Care  •  December  99  Vol  44  No  12 


151' 


Subject  Index  to  Volume  44  (1999) 


Patient  positioning 

automated  rotational  therapy,  for  prevention  of  mechan- 
ical ventilation  complications,  1447 

in  portable  chest  radiography,  1018 

in  respiratory  distress,  686 
Pediatric  respiratory  care.  See  Respiratory  care,  pedi- 
atric 
PEEP.  See  Positive  end-expiratory  pressure  (PEEP) 
Perioperative  care  and  complications 

inhaled  nitric  oxide,  in  heart  and  lung  transplantation, 
205 
Peroxynitrite 

and  inhaled  nitric  oxide,  315,  360 

toxicity,  315 
Personnel 

intubation  responsibilities,  750 
PET  Corner 

flow-volume  loop  analysis  of  airflow  limitation, 
955 
PET  Nuggets:  See  also  Pulmonary  function  testing 

amyotrophic  lateral  sclerosis,  1203 

borderline  normal,  74 

dyspnea,  gradually  increasing,  1205 

forced  expiratory  volume  measurement,  with  modified 
spirometry,  441 

longstanding  dyspnea  on  exertion,  1489 

new  feature  justification,  73 

progressive  dyspnea,  with  clear  chest  roentgenogram, 
961 

progressive  shortness  of  breath,  with  orthopnea,  1491 

pulmonary  clearance,  preoperative,  in  obesity,  959 
Pliarmacology:  See  Drugs  and  drug  therapy 
Piilebotomy 

indications  for  indwelling  arterial  catheter  placement, 
1193 
Pliospliodiesterase  inliibitors 

and  inhaled  nitric  oxide,  331 
Platelet  aggregation 

and  inhaled  nitric  oxide,  184,  315,  340 

in  nitric  oxide  metabolism,  156 
Pleural  abnormalities 

computed  tomography  for,  1 132 
Pleural  effusion 

in  chest  trauma,  1044 

computed  tomography  for,  1078 

neonatal  imaging,  1105 

portable  chest  radiography,  1018 

radiography,  1 1 20 
Pneumatocele 

radiography,  1118 
Pneumobelts 

as  intubation  alternative,  686 
Pneumomediastinum 

radiography,  1119 


Pneumonectomy 

postoperative  radiography,  1078 
Pneumonia 

adenoviral  (case  report),  524 

aspiration,  in  endotracheal  intubation,  604,  828 

neonatal,  imaging  in,  1 103 

nosocomial,  automated  rotational  therapy  for,  1447 

radiography,  in  pediatric  ICU,  1111 
Pneumopericardium 

radiography,  1 1 19 
Pneumothorax 

in  chest  trauma,  1044 

computed  tomography,  1078 

radiography,  in  children,  1 105,  1119 
Positioning.  See  Patient  positioning 
Positive  end-expiratory  pressure  (PEEP):  See  also  Con- 
tinuous positive  airway  pressure  (CPAP) 

inhaled  nitric  oxide  and,  360 

in  mechanical  ventilation  weaning,  421 

tracheal  gas  insufflation,  428,  918 
Postoperative  complications 

radiographic  diagnosis,  in  surgical  ICU,  1078 
Pressure-support  ventilation.  See  Ventilation,  pressure- 
support 
Protocols:  See  also  Guidelines,  recommendations  and 

statements 

oxygen  therapy,  506 

patient-driven 

bronchodilator  therapy  weaning,  497 
utilization  (editorial),  495 

placement  of  indwelling  arterial  catheters,  1 193 

respiratory  care  consult  service 
implementation,  528 
quality  monitoring,  512 
staffing  and  training,  532 

software  reviews 

Mosby's  CPG  mentor:  patient  cases  in  respiratoij 
care,  535 

types  of,  528 
Publication:  See  Writing  for  publication 
Pulmonary  edema 

chest  imaging,  in  cardiac  ICU,  1033 

radiography 

in  children,  1116 

neurogenic,  1064 

Pulmonary  embolism 

in  children,  radiography,  1 122 
Pulmonary  fibrosis 

gradually  increasing  dyspnea  in  (PFT  Nuggets),  1205 

idiopathic,  inhaled  nitric  oxide  for,  212 
Pulmonary  function  testing:  See  also  PET  Corner;  PFT 

Nuggets 

after  weight  loss,  in  obesity,  1458 

book  reviews 


1518 


Respiratory  Care  •  December  99  Vol  44  No  12 


Subject  Index  to  Volume  44  (1999) 


Interpretation  of  pulmonary  function  tests:  a  practi- 
cal ^uide.  1 494 
Manual  of  pulmonary  function  testing,  7th  ed.  965 
borderline  normal  spirograms  (PFT  Nuggets),  74 
neurologic  disorder  and,  1064 
preoperative,  in  obesity  (PFT  Nuggets),  959 
progressive  shortness  of  breath  with  orthopnea  (PFT 

Nuggets),  1491 
respiratory  muscle  stretch  gymnastics  and,  409 
software  reviews 

S'vwBioSvi  PFT  pulmonary  function  test,  702 
Pulmonary  hypertension 

inhaled  nitric  oxide  for,  196,  331.  360 
in  heart  transplantation,  205 
long-term  use,  212 
pathophysiology,  212 
persistent,  in  newborns,  169.  331 
primary,  212 

diagnosis  (PFT  Nuggets),  961 
rebound  hypoxemia  in.  315 
and  right  ventricular  failure,  196 
Pulmonary  infections 

radiography,  in  immunocompromised  children,  1114 
Pulmonary  rehabilitation.  See  Rehabilitation,  pulmo- 
nary 
Pulse  oximeters  and  oximetry.  See  Oximeters  and  oxim- 
etry 
Purchasing 
book  reviews 

Health  devices  sourcebook  1999:  medical  product 
purchasing  directory  with  official  universal  medi- 
cal device  nomenclature  system,  1391 


Quality  assurance  and  control 

respiratory  care  protocol  service,  512 
Quality  of  health  care 

medical  myth  (letter  and  response),  1209 


Racial  factors 

in  diffuse  panbronchiolitis,  1375 
Radiograph  interpretation:  See  also  Test  Your  Radio- 
logic Sl<ill 

in  cardiac  ICU,  1033 
in  portable  chest  radiography.  1018 
in  trauma  ICU,  1044 
Radiography 
book  reviews 

Thoracic  radiology:  the  requisites,  1 1 37 
digital,  1031 
portable 

in  neonatal  and  pediatric  ICU,  1096 

pitfalls  in.  1018 


in  surgical  ICU,  1078 
thoracic 

in  cardiac  ICU,  1033 

chest  radiography  vs.  computed  tomography,  1127 
in  ICU  (editorial),  1015 
in  ICU,  foreword  to  symposium,  1017 
in  neonatal  and  pediatric  ICUs,  1064 
in  neurosciences  ICU,  1064 
in  surgical  ICU,  1064 
in  trauma  ICU,  1044 
Rehabilitation,  pulmonary 
book  reviews 

Pulmonary  rehabilitation  administration  and  patient 

education  manual,  537 
Rehabilitation  of  the  patient  with  respiratory  disease, 
1495 
chest  wall 
editorial,  407 
mobility,  409 
in  chronic  obstructive  pulmonary  disease,  409 
respiratory  muscle  stretch  gymnastics,  409 
Reperfusion  injury.  See  Ischemia-reperfusion  injury 
Research 

patient-centered,  in  artificial  airways,  863 
respiratory  therapist  attitudes  toward  distance  education, 
1337 
Respiration 
book  reviews 

Advances  in  modeling  and  control  of  ventilation,  1 390 
opioid  depression  of,  78 
Respiratory  care:  See  also  Guidelines,  recommenda- 
tions and  statements 
aerosol  therapy  (editorial),  24 
book  reviews 

Respiratory  care  pearls,  536 
consult  service,  quality  monitoring,  512 
protocol  service 

implementation,  528 
staffing  and  training,  532 
software  reviews 

Mosby's  CPG  mentor:  patient  cases  in  respiratory 

care,  535 
UpToDate  in  pulmonary  disease  and  critical  care 
medicine.  111) 
therapist-directed  protocols  (editorial),  495 
Respiratory  care,  neonatal 
catheterization  imaging,  1095 
inhaled  nitric  oxide,  169,  177,  360 
thoracic  imaging,  in  ICU,  1095 
Respiratory  care,  pediatric 

artificial  airway  management.  650 

bronchodilator  weaning,  therapist-directed  protocol,  in 

status  asthmaticus,  497 
and  conscious  sedation  (editorial),  909 


Respiratory  Care  •  December  99  Vol  44  No  12 


151' 


Subject  Index  to  Volume  44  (1999) 


inhaled  nitric  oxide,  177,  281 

orotracheal  intubation,  615 

thoracic  imaging,  in  ICU.  1095 

tracheostomy  tube  placement 
aspiration  in,  851 
and  communications  skills.  845 
feeding  and  swallowing,  850 
Respiratory  care  practitioners 

attitudes  toward  baccalaureate  degree  and  distance  ed- 
ucation, 1337 

and  conscious  sedation  (editorial),  909 

credentialing,  777 

global  respiratory  care  (editorial),  22 

intubation  training.  750.  777 
Respiratory  distress  syndrome,  adult.  See  Acute  respi- 
ratory distress  syndrome  (ARDS) 
Respiratory  distress  syndrome  of  infants  (RDS) 

chest  imaging,  1095 
Respiratory  failure 

acute,  in  chronic  obstructive  pulmonary  disease,  415 

capnography  in  bilateral  transplant,  1207 

hypoxic,  neonatal,  inhaled  nitric  oxide  for,  169 
Respiratory  muscle  stretcli  gymnastics 

for  chronic  obstructive  pulmonary  disease,  409 
Respiratory  system 

heat  and  moisture  exchange,  630 
Resuscitation 

history,  595 
Rotational  therapy 

automated,  for  respiratory  infection  prevention,  1447 


Safety 

mechanical  ventilator  malfunctions,  1 1 83 
Saline 

in  suctioning,  759 
Scoring,  illness  severity 

dependence  nursing  scale,  26 

nursing  work  load,  in  intermediate  ICU,  26,  70 

therapeutic  intervention  scoring  system,  70 
Secretions 

clearance,  604,  686,  759 
Sedation 

conscious,  respiratory  therapist  role  (editorial),  909 

intravenous,  for  endotracheal  intubation,  615 
Sepsis 

animal  models,  308 

inhaled  nitric  oxide  stimulation,  156 

nitric  oxide  in,  308 
Shunt,  cardiopulmonary 

underestimation,  in  hepatopulmonary  syndrome,  1486 
Sickle  cell  disease 

acute  chest  syndrome  in,  1118 

inhaled  nitric  oxide  for,  340 


pathophysiology,  340 
Sleep  apnea 

obstructive  (PFT  Nuggets),  959 
Sleep  disorders 

book  reviews 

Sleep  disorders  sourcebook,  866 
Smoke  inhalation 

acute,  radiography  for,  1114 
Smoking  and  smoking  cessation  : 

dyspnea  in,  76 
Software  reviews 

Mosby  's  CPG  mentor:  patient  cases  in  respiratory  care, 
535 

5v«!BioS>.y  PFT  pulmonary  function  test,  702 

UpToDate  in  pulmonary  disease  and  critical  care  med- 
icine, ITi 
Speech 

in  tracheostomy  tube  placement,  845 
Spirometry:  See  also  Pulmonary  function  testing 

borderline  normal  (PFT  Nuggets).  74 

forced  expiratory  volume,  in  chronic  obstructive  pulmo- 
nary disease  (PFT  Nuggets),  441 

portable  equipment,  performance  comparison,  1465 

Vital  capacity  maneuver  in  modified  spirometry  tech- 
nique (letter  and  response),  1493 
Spontaneous  ventilation.  See  Ventilation,  spontaneous 
Standards 

book  reviews 

Health  standards  1999  official  directory,  1391 
Statistics  and  study  design 

book  reviews 

Introductory  medical  statistics,  3rd  ed.  869 

failure  time  data  analysis,  1 198 

mechanical  ventilator  malfunctions,  survival  analysis, 
1183 

respiratory  therapist  attitudes  toward  distance  education, 
1337 

survival  data  analysis,  1 192 
Status  asthmaticus.  See  Asthma 
Suction  and  suctioning  devices 

atelectasis  during,  759 

endotracheal  tubes,  595,  604 

in  home,  guidelines  for,  99 

hypoxemia  related  to,  759 

in  intubation,  759 
Surveys 

book  reviews 

The  survey  kit,  224 
Survival.  See  Morbidity  and  mortality 
Swallowing 

and  tracheostomy.  850 
Swan-Ganz  catheters.  See  Catheterization,  central  ve- 
nous and  heart 


1520 


Respiratory  Care  •  December  99  Vol  44  No  12 


Subject  Index  to  Volume  44  (1999) 


Temporomandibular  joint  dysfunction 

in  difficult  intubation,  777 
Test  Your  Radiologic  Skill 

dyspnea  on  exertion,  437 
Theory  of  Reasoned  Action  (TRA) 

attitudes  toward  distance  education,  1337 
Thoracic  imaging.  See  Chest  imaging 
Thoracic  injuries 

cardiac  injuries  in,  1044 

computed  tomography  for,  1044,  1133 

radiography,  1 044,  1 1 20 
Thoracotomy 

complications,  radiographic  diagnosis,  1078 
Time  factors 

failure  time  data  analysis,  1 198 
Tomography,  x-ray  computed  (CT) 

in  chest  trauma,  1 044 

diagnostic  accuracy,  1133 

dyspnea  on  exertion,  437 

in  surgical  ICU  patients,  1078 

thoracic,  in  ICU,  1127 

versus  chest  radiography,  1127 
Tracheal  diseases  and  disorders 

bacterial,  endotracheal  intubation  for,  650 

injuries 

from  intubation,  828 
radiography,  1044 

stenosis,  from  tracheotomy,  810,  839 
Tracheal  gas  insufflation.  See  Insufflation,  tracheal  gas 
Tracheoesophageal  fistula 

as  tracheotomy  complication,  838 
Tracheotomy  and  tracheostomy 

benefits,  812 

complications,  807,  828 

decannulation,  856 

history,  595 

indications  for,  807 

long-term,  in  chronic  obstructive  pulmonary  disease 
,415 

percutaneous  dilational,  820 

techniques,  820 

tracheostomy  speaking  valves,  847 

tube  placement 
aspiration  in,  851 
and  communication  skills,  845 
feeding  and  swallowing,  850 
Tracheovascular  fistula 


as  tracheotomy  complication,  839 
Tuberculosis 

book  reviews 

Contagion  and  confinement:  controlling  tuberculosis 
along  the  Skid  Road,  1 392 
Tubes,  endotracheal:  See  also  Intubation,  endotracheal 

in  children,  650 

history,  595 

removal  guidelines,  85 

resistance  to,  604 

types  of,  661 


Vasodilators 

inhaled  nitric  oxide  as,  360 
Ventilation 

mechanical  (See  Mechanical  ventilation) 

negative  pressure,  as  intubation  alternative.  686 

pressure-support,  in  ventilator  weaning,  421 

spontaneous,  281 
Ventilator  circuits 

nitrogen  dioxide  reduction,  281 
Ventilator  dependence 

motor  neuron  disease  in,  case  report,  434 
Vital  capacity 

in  amyotrophic  lateral  sclerosis  (PFT  Nuggets),  1203 

supine  position  and,  443 


Water-electrolyte  balance 

strong  ion  difference,  45 
Weight  loss 

pulmonary  function  following,  in  obesity,  1458 
Wet  lung  disease 

chest  imaging,  1 103 
Work  of  breathing 

endotracheal  tube  resistance,  604 

in  mechanical  ventilation  weaning,  421,  801 
World  Wide  Web 

Website  reviews 

Basic  ECG  interpretation,  1 1 39 
Writing  for  publication 

book  reviews 

Publishing  your  medical  research  paper:  what  they 
don't  teach  in  medical  school,  1496 

X-ray  interpretation.  See  Radiograph  interpretation 


Respiratory  Care  •  December  99  Vol  44  No  12 


152! 


THE  1999  BOUND 
VOLUME  OF 


Respiratory 
Care 

IS  NOW  AVAILABLE 


Volume  44  is  bound  in  a  biue-buckrom  cover  and  may  be  imprinted,  free  of 
chorge,  with  your  name  or  the  name  of  your  orgonization.  Eoch  volume  is 
^40  for  current  AARC  members  and  ^80  for  non-members.  Shipping  is  in- 
cluded for  U.S.  and  Canadian  residents. 

AvDiloble  for  a  limited  hme,  older  bound  volumes  ot  discounted  rotes. 


ORDERS  MUST  BE  PREPAID — INCLUDE  CHECK,  INSTITUTIONAL 
PURCHASE  ORDER,  OR  VALID  CREDIT  CARD  NUMBER. 


n  1999  VOLUME  AT  MO/580 
D  1998  VOLUME  AT  MO/580 
D  1997  VOLUME  AT  540/580 
D  1996  VOLUME  AT  540/580 
n  1995  VOLUME  AT  540/580 
n   CHECK        n   PURCHASE  ORDER 


n  1994  VOLUME  AT  535/575 
n  1993  VOLUME  AT  535/575 
n  1992  VOLUME  AT  530/570 
D  1990  VOLUME  AT  530/570 
n  1989  VOLUME  AT  530/570 

D  VISA        D   MASTERCARD 


CARD  OR  PO' 

EXP. DATE 

SIGNATURE 

AARC  MEMBCR  » 

NAME 

INSTITUTION 

AOORtSS 

CITY 

STATE 

ZIP 

NAME  TO  IMPRINT 

DAEDALUS  ENTERPRISES  INC 
PO  BOX  29686  •  DALLAS  TX  75229  •  FAX  [972]  484  2720 


Support  Your 
ASSOCIATION 


AMERICAN  ASSOCIATION  FOR 
RESPIRATORY  CARE 


Educate  your  patients,  staff,  and  the  public  on 
the  value  of  cardiorespiratory  health  through 
the  books,  manuals,  videos,  posters,  and  even 
T-shirts  available  from  the  AARC.  So  for  RC 
Week  or  year  round,  check  these  pages  for  your 
educational  and  promotional  needs. 

Call  972.243.2272  for  information. 


With  the 


INFO 

SERVICE  CARD 


YOU  CAN  STOP  SEARCHING 

AND  START  BUYING! 

Get  the  facts  on  i|tfie  PRODUCTS 
and  SERVIcKiacivertised 

inpusimBtmiY  ai\id  quickly. 

The  corfiputerized  lnformatiol\Service  Card 

DOES  IT  All 


"i  ^(^  jt\*i§p 


in  your  name  &  adc 
boxes,  ancUra// 


ss,  check  the 
or  fax  it! 


I 


American  Association  for  Respiratory  Care 


JJ. 


Please  read  the  eligibility  requirements  for  each  of  the  classifications  in  the 
right-hand  column,  then  complete  the  applicable  section.  All  information 
requested  below  must  be  provided,  except  where  indicated  as  optional. 
See  other  side  for  more  information  and  fee  schedule.  Please  sign  and  date 
application  on  reverse  side  and  type  or  print  clearly.  Processing  of  applica- 
tion takes  approximately  15  days. 

D  Active 
Associate 

n  Foreign 

n  Physician 

D  Industrial 
n  Special 
n  Student 


Last  Nome  _ 
First  Name 


Social  Security  No. 

Home  Address 

City 


State 


.Zip 


Phone  No. 


Primary  Job  Responsibility  (eheek  one  only) 

I  □  Technical  Director 

n  Assistant  Technical  Director 

D  Pulmonary  Function  Specialist 

D  Instructor/Educator 

n  Supervisor 

D  Staff  Therapist 

n  Staff  Technician 

D  Rehabilitation/Home  Core 

n  Medical  Director 

D  Sales 

D  Student 

D  Other,  specify 


Type  of  Business 

lJ  Hospital 

n  Skilled  Nursing  Facility 

n  DME/HME 

D  Home  Health  Agency 

D   Educational  Institution 

n  Manufacturer  or  supplier 

n  Other,  specify 


Date  of  Birth  (optional)  _ 
J.S,  Citizen?  Yes 


Sex  (optional] 


No 


■iave  you  ever  been  a  member  of  the  AARC? 

so,  when?  From to 


For  office  use  only 


Preferred  mailing  address:    □  Home    □  Business 


FOR  ACTIVE  MEMBER 

An  individual  is  eligible  if  he/she  lives  in  the  U.S.  or  its  territories  or  was  an  Active  Member 
prior  to  moving  outside  its  borders  or  territories,  and  meets  ONE  of  the  following  criteria:  (1 )  is 
legally  credentialed  as  o  respiratory  care  professional  if  employed  in  a  state  that  manaates 
such,  OR  (2)  is  a  graduate  of  on  accredited  educational  program  in  respiratory  core,  OR  [3] 
holds  o  crecienlial  issued  by  the  NBRC.  An  individual  who  is  an  AARC  Active  Member  in  good 
standing  on  December  8,  1 994,  will  continue  as  such  provided  his/her  membership  remains  in 
good  standing. 

PLEASE  USE  THE  ADDRESS  OF  THE  LOCATION  WHERE  YOU  PERFORM  YOUR  JOB,  NOT 
THE  CORPORATE  HEADQUARTERS  IF  IT  IS  LOCATED  ELSEWHERE. 

Place  of  Employment 

Address 

City 


.Zip 


State 

Phone  No.  ( ) 

Medical  Director/Medical  Sponsor 


FOR  ASSOCIATE  OR  SPECIAL  MEMBER 

Individuals  who  hold  a  position  related  to  respirototy  care  but  do  not  meet  the  requirements  of 
Active  Member  shall  be  Associate  Members.  They  hove  all  the  rights  and  benefits  of  the  Asso- 
ciation except  to  hold  office,  vote,  or  serve  as  chair  of  a  standing  committee.  The  follov^ing  sub- 
classes of  Associate  Membership  are  available:  Foreign,  Physician,  and  Industrial  (individuals 
whose  primary  occupation  is  directly  or  indirectly  devoted  to  the  manufacture,  sole,  or  distribu- 
tion of  respiratory  care  eouipment  or  supplies).  Special  Members  ore  those  not  working  in  a 
respiratory  core-related  field. 

PLEASE  USE  THE  ADDRESS  OF  THE  LOCATION  WHERE  YOU  PERFORM  YOUR  JOB,  NOT 
THE  CORPORATE  HEADQUARTERS  IF  IT  IS  LOCATED  ELSEWHERE. 

Place  of  Employment 

Address 

City 

State 


.Zip 


Phone  No. 


FOR  STUDENT  MEMBER 

Individuals  will  be  classified  as  Student  Members  if  they  meet  all  the  requirements  for  Associote 
Membership  and  are  enrolled  in  on  educational  program  in  respiratory  core  accredited  by,  or 
in  the  process  of  seeking  accreditation  from,  on  AARC-recognized  agency. 

SPECIAL  NOTICE  —  Student  Members  do  not  receive  Continuing  Respiratory  Care  Education 
(CRCE)  transcripts.  Upon  completion  of  your  respiratory  care  education,  continuing  education 
credits  may  be  pursued  upon  your  reclassification  to  Active  or  Associate  Member. 

Scfiool/RC  Program 

Address 

City 

State 


.Zip 


Phone  No. 


Length  of  program 

□    1  year 
n  2  years 

Expe€ted  Date  of  Graduation  (REQUIRED 
INFORMATION) 


n  4  years 

n  Other,  specify 


Month 


Year 


American  Association  for  Respiratory  Core  •  1 1030  Abies  Lane  •  Dallas,  TX  75229-4593  •  [972]  243-2272  •  Fox  [972]  4      2720 


American  Association  for  Respiratory  Care 


r^-mji^  1^,  jffBgfkyiMi 


Demographic  Questions 

We  request  that  you  answer  these  questions  in  order  to  help  us 
design  services  and  programs  to  meet  your  needs. 


Check  fhe  Highest  Degree  Earned 

n  High  School 

D  RC  Graduate  Technician 

n  Associate  Degree 

n  Bachelor's  Degree 

n  Master's  Degree 

n  Doctorate  Degree 


Number  et  Years  in  Respiratory  Care 

D  0-2  years  □    11-15  Years 

n  3-5  years  D   1 6  years  or  more 

n  6-10  years 


Job  Status 

D  Full  Time 

D  Part  Time 

Credentials 

n  RRT 

D  CRT 

D  Physician 

D  CRNA 

D  RN 

Salary 

D  Less  than  $10,000 

D  $10,001 -$20,000 

n  $20,001 -$30,000 

D  $30,001 -$40,000 

n  $40,000  or  more 

D  LVN/LPN 

D  CPFT 

D  RPFT 

n  Perinatal/Pediatric 


PLEASE  SIGN 

\  hereby  apply  for  membership  in  the  American  Association  for  Respiratory  Care 
and  hove  enclosed  my  dues.  If  approved  for  membership  in  the  AARC,  I  will  abide 
by  its  bylaws  and  professional  code  of  ethics.  I  authorize  investigation  of  all  state- 
ments contained  herein  and  understand  that  misrepresentations  or  omissions  of 
facts  called  for  is  cause  for  rejection  or  expulsion. 

A  yearly  subscription  to  RESPIRATORY  CARE  journal  and  AARC  Times  magazine 
includes  an  allocation  of  $1  1 .50  from  my  dues  for  each  of  these  publications. 

NOTE:  Contributions  or  gifts  to  the  AARC  are  not  tax  deductible  as  charitable  con- 
tributions for  income  tax  purposes.  However,  they  may  be  tax  deductible  as  ordi- 
nary and  necessary  business  expenses  subject  to  restrictions  imposed  as  a  result  of 
association  lobbying  activities.  The  AARC  estimates  that  the  nondeductible  portion 
of  your  dues  —  the  portion  v/hich  is  allocable  to  lobbying  —  is  26%. 


Signature 
DafB 


Membership  Fees 

Payment  must  accompany  your  application  to  the  AARC.  Fees  are  for  12 
months.  (NOTE:  Renewal  fees  are  $75.00  Active,  Associate-Industrial  or  Associ- 
ate-Physician, or  Special  status;  $90.00  for  Associate-Foreign  status;  and 
$45.00  for  Student  status). 


n  Active 

$  87.50 

D  Associate  (Industrial  or  Physician) 

$  87.50 

D  Associate  (Foreign) 

$102.50 

n  Special 

$  87.50 

D  Student 

$  45.00 

TOTAL 

$ 

Spetialty  Settions 

Established  to  recognize  the  specialty  areas  of  respiratory  care,  these  sections 
publish  a  bi-monthly  newsletter  that  focuses  on  issues  of  specific  concern  to  that 
specialty.  The  sections  also  design  the  specialty  programming  at  the  national 
AARC  meetings. 

n  Adult  Acute  Care  Section 
n   Education  Section 
n  Perinatal-Pediatric  Section 
D  Diagnostics  Section 
n  Continuing  Care- 
Rehabilitation  Section 
n  Management  Section 
D  Transport  Section 
n  Home  Care  Section 
n  Subacute  Care  Section 

TOTAL 

GRAND  TOTAL  =  Membership  Fee 
plus  optional  seetions 


$15.00 

$20.00 

$15.00 

$15.00 

$15.00 

$20.00 

$15.00 

$15.00 

$15.00 

$ 

$ 

D  Total  Amount  Enclosed/Charged      $_ 
n  Please  charge  my  dues  (see  below) 


To  charge  your  dues,  complete  the  following: 
n  MasterCard 
n  Visa 

Card  Number 


Card  Expires /_ 

Signature 


Mail  application  and  appropriate  fees  to: 
£rkcn  Association  for  Respiratory  Core  •  11 030  Abies  Lane  •  Dallas,  TX  75229-4593  •  [972]  243-2272  •  Fax  [972]  484-2720 


1 


Respiratory  Care  •  Open  Forum  2000 


The  American  Association  for  Respiratory  Care  and  its  sci- 
ence journal.  Respiratory  Care,  invite  submission  of  brief 
abstracts  related  to  any  aspect  of  cardiorespiratory  care.  The 
abstracts  will  be  reviewed,  and  selected  authors  will  be  invited 
to  present  posters  at  the  OPEN  FORUM  during  the  AARC  In- 
ternational Respiratory  Congress  in  Cincinnati,  Ohio,  October 
7-10, 2000.  Accepted  abstracts  will  be  published  in  the  Au- 
gust 2000  issue  of  RESPIRATORY  CARE.  Membership  in  the 
AARC  is  not  required  for  participation.  All  accepted  abstracts 
are  automatically  considered  for  ARCF  research  grants. 

SPECIFICATIONS— READ  CAREFULLY! 

An  abstract  may  report  (1)  an  original  study,  (2)  the  eval- 
uation of  a  method,  device  or  protocol,  or  (3)  a  case  or  case 
series.  Topics  may  be  aspects  of  adult  acute  care,  continuing 
care/rehabilitation,  perinatology/pediatrics,  cardiopulmonary 
technology,  or  health  care  delivery.  The  abstract  may  have  been 
presented  previously  at  a  local  or  regional — but  not  nation- 
al— meeting  and  should  not  have  been  published  previously 
in  a  national  journal.  The  abstract  will  be  the  only  evidence 
by  which  the  reviewers  can  decide  whether  the  author  should 
be  invited  to  present  a  poster  at  the  Open  Forum.  Therefore, 
the  abstract  must  provide  all  important  data,  findings,  and  con- 
clusions. Give  specific  information.  Do  not  write  such  gen- 
eral statements  as  "Results  will  be  presented"  or  "Significance 
will  be  discussed." 

ESSENTIAL  CONTENT  ELEMENTS 

Original  study.  Abstract  must  include  ( 1 )  Background:  state- 
ment of  research  problem,  question,  or  hypothesis;  (2)  Method: 
description  of  research  design  and  conduct  in  sufficient  de- 
tail to  permit  judgment  of  validity;  (3)  Results:  statement  of 
research  findings  with  quantitative  data  and  statistical  anal- 
ysis; (4)  Conclusions:  interpretation  of  the  meaning  of  the  re- 
sults. 

Method,  device,  or  protocal  valuation.  Abstract  must  in- 
clude ( 1 )  Background:  identification  of  the  method,  device, 
or  protocol  and  its  intended  function;  (2)  Method:  description 
of  the  evaluation  in  sufficient  detail  to  permit  judgment  of  its 
objectivity  and  validity;  (3)  Results:  findings  of  the  evalua- 
tion; (4)  Experience:  summary  of  the  author's  practical  ex- 
perience or  a  lack  of  experience;  (5)  Conclusions:  interpre- 
tation of  the  evaluation  and  experience.  Cost  comparisons  should 
be  included  where  possible  and  appropriate. 

Case  report.  Abstract  must  report  a  case  that  is  uncommon 
or  of  exceptional  educational  value  and  must  include  ( 1 )  In- 
troduction: relevant  basic  information  important  to  understanding 
the  case.  (2)  Case  Summary:  patient  data  and  response,  de- 
tails of  interventions.  (3)  Discussion:  content  should  reflect 
results  of  literature  review.  The  author(s)  should  have  been 
actively  involved  in  the  case  and  a  case-managing  physician 
must  be  a  co-author  or  must  approve  the  report. 


FORMAT  AND  TYPING  INSTRUCTIONS 

Accepted  abstracts  will  be  photographed  and  reduced  by 
40%;  therefore,  the  size  of  the  original  text  should  be  at  least 
10  points.  A  font  like  Helvetica  or  Times  makes  the  clearest 
reproduction.  The  first  line  of  the  abstract  should  be  the  title 
in  all  capital  letters.  Title  should  explain  content.  Follow  title 
with  names  of  all  authors  (including  credentials),  institution(s), 
and  location;  underline  presenter's  name.  Type  or  electron- 
ically print  the  abstract  single  spaced  in  one  paragraph  on  a 
clean  sheet  of  paper,  using  margins  set  so  that  the  abstract 
will  fit  into  a  box  no  bigger  than  18.8  cm  (7.4")  by  13.9  cm 
(5.5"),  as  shown  on  the  reverse  of  this  page.  Insert  only  one 
letter  space  between  sentences.  Text  submission  on  diskette 
is  allowed  but  must  be  accompanied  by  a  hard  copy.  Data  may 
be  submitted  in  table  form,  and  simple  figures  may  be  included 
provided  they  fit  within  the  space  allotted.  No  figure,  illustration, 
or  table  is  to  be  attached  to  the  abstract  form.  Provide  all  au- 
thor information  requested.  Standard  abbreviations  may  be  em- 
ployed without  explanation;  new  or  infrequently  used  ab- 
breviations should  be  spelled  out  on  first  use.  Any  recurring 
phrase  or  expression  may  be  abbreviated,  if  it  is  fu^t  explained. 
Check  the  abstract  for  ( 1 )  errors  in  spelling,  grammar,  facts, 
and  figures;  (2)  clarity  of  language;  and  (3)  conformance  to 
these  specifications.  An  abstract  not  prepared  as  requested  may 
not  be  reviewed.  Questions  about  abstract  preparation  may  be 
telephoned  to  Linda  Barcus  at  (972)  406-4667. 

Early  Deadline  Allowing  Revision.  Authors  may  choose 
to  submit  abstracts  early.  Abstracts  postmarked  by  February 
29,  2000  will  be  reviewed  and  the  authors  notified  by  letter 
only  to  be  mailed  by  March  3 1 ,  2000.  Rejected  abstracts  will 
be  accompanied  by  a  written  critique  that  should,  in  many  cases, 
enable  authors  to  revise  their  abstracts  and  resubmit  them  by 
the  Final  Deadline  (April  28,  2000). 

Final  Deadline.  The  mandatory  Final  Deadline  is  April  28, 
2000  (postmark).  Authors  will  be  notified  of  acceptance  or  re- 
jection by  letter  only.  These  letters  will  be  mailed  by  July  12, 
2000. 

Mailing  Instructions.  Mail  (Do  not  fax!)  2  clear  copies 
of  the  completed  abstract  form,  diskette  (if  possible),  and  a 
stamped,  self-addressed  postcard  (for  notice  of  receipt)  to: 

2000  Respiratory  Care  Open  Forum 

11030  Abies  Lane 

Dallas  TX  75229-4593 


submit  your  Open  Forum  abstract  electronically 

,    visitwww.rcjoumal.com  , 


Respiratory  Care  Open  Forum  2000  Abstract  Form 


13.9  cm  or  5.5" 


1 .  Title  must  be  in  all 
upper  case  (capital) 
letters,  authors'  full 
names  and  text  in 
upper  and  lower  case. 

2.  Follow  title  with  all 
authors'  names 
including  credentials 
(underline  presenter's 
name),  institution,  and 
location. 

3.  Do  not  justify  (ie, 
leave  a  'ragged'  right 
margin). 

4.  Do  not  use  type  size 
less  than  10  points. 

5.  All  text  and  the  table, 
or  figure,  must  fit  into 
the  rectangle  shown. 
(Use  only  1  clear,  con- 
cise table  or  figure.) 

6.  Submit  2  clean  copies. 

Mail  original  &  1 
photocopy  (along  with 
postage-paid  postcard)  to 

2000  Respiratory 
Cark  Open  Forum 

11030  Abies  Lane 
Dallas  TX  75229-4593 

Early  deadline  is 
February  28,  2000 
(postmark) 

Final  deadline  is 
April  28,  2000 
(postmark) 


Electronic 
Submission  Is  Now 

Available.  Visit 
www.rcjournal.com 

to  find  out  more 


Name  &  Credentials 


Mailing  Address 


Voice  Phone  &  Fax 


Name  &  Credentials 


Mailing  Address 


Voice  Phone  &  Fax 


RE/PIRATORy  CARE 


Manuscript  Preparation  Guide 


General  Information 

RESPIRATORY  CARE  welcomes  original  manuscripts  related  to  the 
science  and  technology  of  respiratory  care  and  prepared  accord- 
ing to  these  Instructions  and  the  Uniform  Requirements  for 
Manuscripts  Submitted  to  Biomedical  Journals  f  Respir  Care  1 997; 
42(6):623-634].  Manuscripts  are  blinded  and  reviewed  by  pro- 
fessionals who  are  experts  in  their  fields.  Authors  are  responsible 
for  all  aspects  of  the  manuscript  and  receive  galleys  to  proofread 
before  publication.  Each  accepted  manuscript  is  copyedited  so  that 
its  message  is  clear  and  it  conforms  to  the  Journal's  style.  Published 
papers  are  copyrighted  by  Daedalus  Inc  and  may  not  be  published 
elsewhere  without  permission. 

Editorial  consultation  is  available  at  any  stage  of  planning  or  writ- 
ing. On  request,  specific  guidance  is  provided  for  all  publication  cat- 
egories. To  receive  these  Instructions  and  related  materials,  write 
to  Respiratory  Care,  600  Ninth  Avenue,  Suite  702,  Seattle  WA 
98104,  call  (206)  223-0558,  or  fax  (206)  223-0563. 

Publication  Categories  &  Structure 

Research  Article:  A  report  of  an  original  investigation  (a  study). 
It  includes  a  Title  Page,  Abstract,  Introduction,  Methods.  Results, 
Discussion,  Conclusions,  Product  Sources,  Acknowledgments,  Ref- 
erences, Tables,  Appendices,  Figures,  and  Figure  Captions. 

Evaluation  of  Device/Method/Technique:  A  description  and  eval- 
uation of  an  old  or  new  device,  method,  technique,  or  modification. 
It  has  a  Title  Page,  Abstract,  Introduction,  Description  of  De- 
vice/Method/Technique, Evaluation  Methods,  Evaluation  Results, 
Discussion.  Conclusions,  Product  Sources,  Acknowledgments,  Ref- 
erences, Tables,  Appendices,  Figures,  and  Figure  Captions.  Com- 
parative cost  data  should  be  included  wherever  possible. 

Case  Report:  A  report  of  a  clinical  case  that  is  uncommon,  or  was 
managed  in  a  new  way,  or  is  exceptionally  instructive.  All  authors 
must  be  associated  with  the  case.  A  case-managing  physician  must 
either  be  an  author  or  furnish  a  letter  approving  the  manuscript.  Its 
components  are  Title  Page,  Abstract,  Introduction,  Case  Summa- 
ry, Discussion,  References,  Tables,  Figures,  and  Figure  Captions. 

Review  Article:  A  comprehensive,  critical  review  of  the  literature 
and  state-of-the-art  summary  of  a  pertinent  topic  that  has  been  the 
subject  of  at  least  40  published  research  articles.  Title  Page,  Out- 
line, Introduction,  Review  of  the  Literature,  Summary.  Acknowl- 
edgments, References.  Tables,  Appendices,  and  Figures  and  Cap- 
tions may  be  included. 

Overview:  A  critical  review  of  a  pertinent  topic  that  has  fewer  than 
40  published  research  articles. 

Update:  A  report  of  subsequent  developments  in  a  topic  that  has 
been  critically  reviewed  in  this  Journal  or  elsewhere. 


Point-of-View  Paper:  A  paper  expressing  personal  but  substanti- 
ated opinions  on  a  pertinent  topic.  Title  Page,  Text,  References,  Tables, 
and  Illustrations  may  be  included. 

Special  Article:  A  pertinent  paper  not  fitting  one  of  the  foregoing 
categories  may  be  acceptable  as  a  Special  Article.  Consult  with  the 
Editor  before  writing  or  submitting  such  a  paper. 

Editorial:  A  paper  drawing  attention  to  a  pertinent  concern;  it  may 
present  an  opposing  opinion,  clarify  a  position,  or  bring  a  problem 
into  focus. 

Letter:  A  signed  communication,  marked  "For  publication," 
about  prior  publications  in  this  Journal  or  about  other  pertinent  top- 
ics. Tables  and  illustrations  may  be  included. 

Blood  Gas  Corner:  A  brief,  instructive  case  report  involving  blood 
gas  values — with  Questions,  Answers,  and  Discussion. 

Drug  Capsule:  A  mini-review  paper  about  a  drug  or  class  of  drugs 
that  includes  discussions  of  pharmacology,  pharmacokinetics, 
and  pharmacotherapy. 

Graphics  Comer:  A  briefcase  report  incorporating  waveforms  for 
monitoring  or  diagnosis — with  (Questions,  Answers,  and  Discussion. 

Kittredge's  Comer:  A  brief  description  of  the  operation  of  respiratory 
care  equipment — with  information  from  manufacturers  and  edito- 
rial comments  and  suggestions. 

PFT  Corner:  Like  Blood  Gas  Comer,  but  involving  pulmonary 
function  tests. 

Cardiorespiratory  Interactions.  A  case  report  demonstrating  the 
interaction  between  the  cardiovascular  and  respiratory  systems.  It 
should  be  a  patient-care  scenario;  however,  the  case — the  central 
theme — is  the  systems  interaction.  CRl  is  characterized  by  figures, 
equations,  and  a  glossary.  See  the  March  1996  Issue  of  RESPIRA- 
TORY Care  for  more  detail. 

Test  Your  Radiologic  Skill:  Like  Blood  Gas  Corner,  but  involv- 
ing pulmon;iry  medicine  radiography  and  including  one  or  more  radio- 
graphs; may  involve  imaging  techniques  other  than  conventional 
chest  radiography. 

Review  of  Book,  Film,  Tape,  or  Software:  A  balanced,  critical 
review  of  a  recent  release. 

Preparing  the  Manuscript 

Print  on  one  side  of  white  bond  paper.  8.5  in.  x  1 1  in.  (216  x  279  mm) 
with  margins  of  at  least  I  in.  (25  mm)  on  all  sides  of  the  page.  Use 
double-spacing  throughout  the  entire  manuscript.  Use  a  standard 
font  (eg.  Times,  Helvetica,  or  Courier)  at  least  1 0  points  in  size,  and 


Respiratory  Care  Manuscript  Preparation  Guide,  Revised  2/98 


Manuscript  Preparation  Guide 


do  not  use  italics  except  for  special  emphasis.  Number  all  pages  in 
upper-right  comers.  Indent  paragraphs  5  spaces.  Do  not  justify.  Do 
not  put  authors'  names,  institutional  affiliations  or  allusions  to 
institutional  affiliations  in  the  text,  or  other  identification  any- 
where except  on  the  title  page.  Repeat  title  only  (no  authors)  on 
the  abstract  page.  Begin  each  of  the  following  on  a  new  page:  Title 
Page,  Abstract,  Text,  Product  Sources  List,  Acknowledgments,  Ref- 
erences, each  Table,  and  each  Appendix.  Use  standard  English  in 
the  first  person  and  active  voice. 

Center  main  section  headings  on  the  page  and  type  them  in  cap- 
ital and  small  letters  (eg,  Introduction,  Methods,  Results,  Discus- 
sion). Begin  subheadings  at  the  left  margin  and  type  them  in  cap- 
ital and  small  letters  (eg.  Patients,  Equipment,  Statistical  Analysis). 

References.  Cite  only  published  works  as  references.  Manuscripts 
accepted  but  not  yet  published  may  be  cited  as  references:  desig- 
nate the  accepting  journal,  followed  by  (in  press),  and  provide  3  copies 
of  the  in-press  article  for  reviewer  inspection.  Cite  references  in  the 
text  with  superscript  numerals.  Assign  numbers  in  the  order  that  ref- 
erences are  first  cited.  On  the  reference  page,  list  the  cited  works 
in  numerical  order.  Follow  the  Journal's  style  for  references.  Abbre- 
viate journal  names  as  in  Index  Medicus.  List  all  authors. 

Article  in  a  journal  carrying  pagination  throughout  volume: 

Rau  JL,  Harwood  RJ.  Comparison  of  nebulizer  delivery  methods 
through  a  neonatal  endotracheal  tube:  a  bench  study.  Respir  Care 
1992;37(11):1233-1240. 

Article  in  a  publication  that  numbers  each  issue  beginning  with 
Page  1: 

Bunch  D.  Establishing  a  national  database  for  home  care.  AARC  Times 

1991  ;15(Mar):6 1,62,64. 

Corporate  author  journal  article: 

American  Association  for  Respiratory  Care.  Criteria  for  establish- 
ing units  for  chronic  ventilator-dependent  patients  in  hospitals.  Respir 
Care  1988;33(1 1);1044-1046. 

Article  in  journal  supplement:  (Journals  differ  in  their  methods  of 
numbering  and  identifying  supplements.  Supply  sufficient  information 
to  promote  retrieval.) 

Reynolds  HY.  Idiopathic  interstitial  pulmonary  fibrosis.  Chest  1986; 

89(3Suppl):l39S-143S. 

Abstract  in  journal:  (Abstracts  citations  are  to  be  avoided.  Those  more 
than  3  years  old  should  not  be  cited.) 

Stevens  DP.  Scavenging  ribavirin  from  an  oxygen  hood  to  reduce  envi- 
ronmental exposure  (abstfact).  Respir  Care  1990;35(11):  1087-1088. 

Editorial  in  journal: 

Enright  P.  Can  we  relax  during  spirometry?  (editorial).  Am  Rev  Respir 
Dis  1993;I48(2):274. 

Editorial  with  no  author  given: 

Negative-pressure  ventilation  for  chronic  obsUTJCtive  pulmonary  dis- 
ease (editorial).  Lancet  1992;340(8833):1440-1441. 

Letter  in  journal: 

Aelony  Y.  Ethnic  norms  for  pulmonary  funcrion  tests  (letter).  Chest 
199 1;99(4):  1051. 


Paper  accepted  but  not  yet  published: 

Hess  D.  New  therapies  for  asthma.  Respir  Care  (year,  in  press). 

Personal  author  book:  (For  any  book,  specific  pages  should  be  cited 
whenever  possible.) 

DeRemee  RA.  Clinical  profiles  of  diffuse  interstitial  pulmonary  dis- 
ease. New  York:  Futura;  1990.  p.  76-85. 

Corporate  author  book: 

American  Medical  Association  Department  of  Dmgs.  AMA  drug  eval- 
uations, 3rd  ed.  Litdeton  CO:  Publishing  Sciences  Group;  1977. 

Chapter  in  book  with  editor(s): 

Pierce  AK.  Acute  respiratory  failure.  In:  Guenter  CA,  Welch  MH,  edi- 
tors. Pulmonary  medicine.  Philadelphia:  JB  Lippincott;  1977:26-42. 

Tables.  Use  consecutively  numbered  tables  to  display  information. 
Start  each  table  on  a  separate  page.  Number  and  title  the  table  and 
give  each  column  a  brief  heading.  Place  explanations  in  footnotes, 
including  all  nonstandard  abbreviations  and  symbols.  Key  the  foot- 
notes with  conventional  designations  (*,  t,  t,  §,  II,  I,  **,  tt)  in  con- 
sistent order,  placing  them  superscript  in  the  table  body.  Do  not  use 
horizontal  or  vertical  rules  or  borders.  Do  not  submit  tables  as  pho- 
tographs, reduced  in  size,  or  on  oversize  paper.  Use  the  same  type- 
face as  in  the  text. 

Illustrations.  Graphs,  line  drawings,  photographs,  and  radiographs 
are  figures.  Use  only  illustrations  that  clarify  and  augment  the  text. 
Number  them  consecutively  as  Fig.  1 ,  Fig.  2,  and  so  forth  accord- 
ing to  the  order  by  which  they  are  mentioned  in  the  text.  Be  sure 
all  figures  are  cited.  If  any  figure  was  previously  published,  include 
copyright  holder's  written  permission  to  reproduce.  Figures  for 
publication  must  be  of  professional  quality.  Data  for  the  original 
graphs  should  be  available  to  the  Editor  upon  request.  If  color  is  essen- 
tial, consult  the  Editor  for  more  information.  In  reports  of  animal 
experiments,  use  schematic  drawings,  not  photographs.  A  letter  of 
consent  must  accompany  any  photograph  of  a  person.  Do  not  place 
titles  and  detailed  explanations  on  figures;  put  this  information  in 
figure  captions.  If  possible,  submit  radiographs  as  prints  and  full- 
size  copies  of  film. 

Drugs.  Identify  precisely  all  drugs  and  chemicals  used,  giving  gener- 
ic names,  doses,  and  routes  of  administration.  If  desired,  brand  names 
may  be  given  in  parentheses  after  generic  names.  Drugs  should  be 
listed  on  the  product-sources  page. 

Commercial  Products.  In  parentheses  in  the  text,  identify  any  com- 
mercial product  (including  model  number  if  applicable)  the  first  time 
it  is  mentioned,  giving  the  manufacturer's  name,  city,  and  state  or 
country.  If  four  or  more  products  are  mentioned,  do  not  list  any  man- 
ufacturers in  the  text;  instead,  list  them  on  a  Product  Sources  page 
at  the  end  of  the  text,  before  the  References.  Provide  model  num- 
bers when  available  and  manufacturer's  suggested  price,  if  the  study 
has  cost  implications. 

Ethics.  When  reporting  experiments  on  human  subjects,  indicate 
that  procedures  were  conducted  in  accordance  with  the  ethical  stan- 
dards of  the  World  Medical  Association  Declaration  of  Helsinki 
[Respir  Care  1997;42(6):635-636]  or  of  the  institution's  committee 


RESPIRATORY  CARE  Manuscript  Preparation  Guide,  Revised  2/98 


Manuscript  Preparation  Guide 


on  human  experimentation.  State  that  informed  consent  was 
obtained.  Do  not  use  patient's  names,  initials,  or  hospital  numbers 
in  text  or  illustrations.  When  reporting  experiments  on  animals,  indi- 
cate that  the  institution's  policy,  a  national  guideline,  or  a  law  on 
the  care  and  use  of  laboratory  animals  was  followed. 

Statistics.  Identify  the  statistical  tests  used  in  analyzing  the  data, 
and  give  the  prospectively  determined  level  of  significance  in  the 
Methods  section.  Report  actual  p  values  in  Results.  Cite  only  text- 
book and  published  article  references  to  support  choices  of  tests.  Iden- 
tify any  general-use  or  commercial  computer  programs  used,  nam- 
ing manufacturers  and  their  locations.  These  should  be  listed  on  the 
product-sources  page. 

Units  of  Measurement.  Express  measurements  of  length,  height, 
weight,  and  volume  in  metric  units  appropriately  abbreviated;  tem- 
peratures in  degrees  Celsius;  and  blood  pressures  in  millimeters  of 
mercury  (mm  Hg).  Report  hematologic  and  clinical-chemistry  mea- 
surements in  conventional  metric  and  in  SI  (Systeme  Internationale) 
units.  Show  gas  pressures  (including  blood  gas  tensions)  in  torr. 
List  SI  equivalent  values,  when  possible,  in  brackets  following  non- 
SI  values— for  example,  "PEEP,  10  cm  H2O  [0.98 1  kPa]."  For  con- 
version to  SI,  see  RESPIRATORY  CARE  1988;33(10):861-873  (Oct 
1988),  1989;34(2):145  (Feb  1989),  and  1997;42(6):639-640  (June 
1997). 

Conflict  of  Interest  Authors  are  asked  to  disclose  any  liaison  or  finan- 
cial arrangement  they  have  with  a  manufacturer  or  distributor  whose 
product  is  part  of  the  submitted  manuscript  or  with  the  manufacturer 
or  distributor  of  a  competing  product.  (Such  arrangements  do  not 
disqualify  a  paper  from  consideration  and  are  not  disclosed  to  review- 
ers.) A  statement  to  this  effect  is  included  on  the  cover-letter  page. 
(Reviewers  are  screened  for  possible  conflict  of  interest.) 

Abbreviations  and  Symbols.  Use  standard  abbreviations  and  sym- 
bols. Avoid  creating  new  abbreviations.  Avoid  all  abbreviations 
in  the  title  and  unusual  abbreviations  in  the  abstract.  Use  an  abbre- 
viation only  if  the  term  occurs  several  times  in  the  paper.  Write  out 
the  full  term  the  first  time  it  appears,  followed  by  the  abbreviation 
in  parentheses.  Thereafter,  employ  the  abbreviation  alone.  Never 
use  an  abbreviation  without  defining  it.  Standard  units  of  mea- 
surement can  be  abbreviated  without  explanation  (eg,  10  L/min, 
15  torr,  2.3  kPa). 

Please  use  the  following  forms:  cm  H2O  (not  cmH20),  f  (not  bpm), 
L  (not  1),  LVmin  (not  LPM,  l/min,  or  1pm),  mL  (not  ml),  mm  Hg  (not 
mmHg),  pH  (not  Ph  or  PH),  p  >  0.001  (not  p>0.001),  s  (not  sec), 
SpO:  (pulse-oximetry  saturation).  See  RESPIRATORY  CARE: 
Standard  Abbreviations  and  Symbols  [Respir  Care  1997;42(6):637- 
642]. 

Submitting  the  Manuscript 

Mail  three  copies  [  1  copy  with  author(s)  name(s),  affiliation(s),  2 
copies  without  name(s)  and  affiliation(s)  for  reviewers]  of  the  manu- 
script, figures,  and  1  diskette,  and  the  Cover  Letter  &  Checklist  to 
RESPIRATORY  CARE,  600  Ninth  Avenue,  Suite  702,  Seattle  WA 
98104.  Do  not  fax  manuscripts.  Protect  figures  with  cardboard.  Keep 
a  copy  of  the  manuscript  and  figures.  Receipt  of  your  manuscript 


will  be  acknowledged. 

Computer  Diskettes.  Authors  are  encouraged  to  submit  electron- 
ic versions  of  manuscripts  as  well  as  printed  copies  (3.5  in.  diskettes 
in  Macintosh  or  IBM-DOS  format).  Label  each  diskette  with  date; 
author's  name;  name  and  version  of  word-processing  program  used; 
and  filename(s).  Software  used  to  produce  graphics  and  tables  should 
be  similarly  identified.  Do  not  write  on  diskette  labels  except  with 
felt-tipped  pen.  If  revision  of  a  manuscript  is  required  as  a  condi- 
tion of  acceptance  for  publication,  we  ask  that  an  electronic  version 
of  revision  be  supplied  to  facilitate  copyediting  and  production. 

Prior  and  Duplicate  Publication.  Work  that  has  been  published 
or  accepted  elsewhere  should  not  be  submitted.  In  special  instances, 
the  Editor  may  consider  such  material,  provided  that  permission  to 
publish  is  given  by  the  author  and  original  publisher.  Please  con- 
sult the  Editor  before  submitting  such  work. 

Authorship.  All  persons  listed  as  authors  should  have  participat- 
ed in  the  reported  work  and  in  the  shaping  of  the  manuscript;  all  must 
have  proofread  the  submitted  manuscript;  and  all  should  be  able  to 
publicly  discuss  and  defend  the  paper's  content.  A  paper  with  cor- 
porate authorship  must  specify  the  key  persons  responsible  for  the 
article.  Authorship  is  not  justified  solely  on  the  basis  of  solicitation 
of  funding,  collection  or  analysis  of  data,  provision  of  advice,  or  sim- 
ilar services.  Persons  who  provide  such  ancillary  services  exclusively 
may  be  recognized  in  an  Acknowledgments  section. 

Permissions.  The  manuscript  must  be  accompanied  by  copies  of 
permissions  to  reproduce  previously  published  material  (figures  or 
tables);  to  use  illustrations  of,  or  report  sensitive  personal  information 
about,  identifiable  persons;  and  to  name  persons  in  the  Acknowl- 
edgments section. 

Reviewers.  Please  supply  the  names,  credentials,  affiliations,  address- 
es, and  phone/fax  numbers  of  three  professionals  whom  you  con- 
sider expert  on  the  topic  of  your  paper.  Your  manuscript  may  be  sent 
to  one  or  more  of  them  for  blind  peer  review. 


Editorial  Office: 

RESPIRATORY  CARE 

600  Ninth  Avenue,  Suite  702 

Seattle  WA  98104 

(206)  223-0558  (voice) 

(206)  223-0563  (fax) 

e-mail:  rcjournal@aarc.org 

kreilkamp(s' aarc.org 


Respiratory  Care  Manuscript  Preparation  Guide,  Revised  2/98 


COVER  LETTER  &  CHECKLIST 

A  copy  of  this  completed  form  must  accompany  all  manuscripts  submitted  for  publication. 


Title  of  Paper: 


Publication  Category: 


Corresponding  Author: . 
Mailing  Address: 


Reprints:     □  Yes    □  No 


_Phone: 


FAX: 


E-mail  Address: 


"We,  the  undersigned,  have  all  participated  in  the  work  reported,  proofread  the  accompanying  manuscript,  and  approve  its  sub- 
mission for  publication."  Please  print  and  include  credentials,  title,  institution,  academic  appointments,  city  and  state.  If  more 
than  4  authors,  please  use  another  copy  of  this  form.* 


'First  Author: 


'Second  Author: 


*Third  Author: 


Author  Signature/Date. 


Author  Signature/Date_ 


Author  Signature/Date, 


'Fourth  Author: 


Author  Signature/Date, 


Has  this  research  been  presented  in  any  public  forum?       □  Yes    □  No 
If  yes,  where,  when  and  by  whom? 


Has  this  research  received  any  awards?         □  Yes    □  No 
If  yes,  please  describe. 


Has  this  research  received  any  grants  or  other  support,  financial  or  material?      □  Yes    □  No 
If  yes,  please  describe. 


Do  any  of  the  authors  of  this  manuscript  have  a  financial  interest  in  (or  a  commercial  or  consulting  relationship  to)  any  of  the 
products  or  manufacturers  mentioned  in  this  paper  or  any  competing  products  or  manufacturers?        □  Yes    □  No 


If  yes,  please  describe. 


□  Have  you  enclosed  a  copy  of  the  manuscript  on  diskette? 

□  Is  double-spacing  used  throughout  entire  manuscript? 

□  Are  all  pages  numbered  in  upper-right  corners? 

□  Are  all  references,  figures,  and  tables  cited  in  the  text? 

□  Has  the  accuracy  of  the  references  been  checked,  and  are  they  correctly  formatted? 

□  Have  SI  values  been  provided? 

□  Has  all  arithmetic  been  checked? 

□  Have  generic  names  of  drugs  been  provided? 

□  Have  necessary  written  permissions  been  provided? 

□  Have  authors'  names  been  omitted  from  text  and  figure  labels? 

□  Have  copies  of  'in  press'  references  been  provided? 

□  Has  the  manuscript  been  proofread  by  all  the  authors? 

□  Have  the  manufacturers  and  their  locations  been  provided  for  all  devices  and  equipment  used? 


Respiratory  Care  Manuscript  Preparation  Guide,  Revised  2/98 


MEE^JfccH 


For  VOLUNTARY  reporting 

by  health  professionals  of  adverse 

events  and  product  problems 


FOA  Use  Only  (Resp  Care) 


THE    IDA    MEDICAL    PRODUCTS    REPORTING    PROGRAM 


A.  Patient  information 


1    Patient  identifier 


In  confidence 


2.  Age  at  time 
of  event: 

or  


Date 
of  birth: 


3  Sex 

I    I  female 
I     I  male 


Page 


4.  Weiglit 


of 


Triage  unit 
sequence  # 


-lbs 
kgs 


B.  Adverse  event  or  product  problem 


1,  LH  Adverse  event      and/or  |     |  Product  problem  (e.g..  defects/malfunctions) 


2    Outcomes  attributed  to  adverse  event      . — . 

(check  all  that  apply)  l_l  disability 

I    I  congenital  anomaly 

'I  \_\  required  intervention  to  prevent 

permanent  impairment/damage 


Q  death 


I    I  life-threatening 

I     I  hospitalization  -  initial  or  prolonged       LJ  o'her: 


3  Date  of 
event 

■      lay  yr) 


4  Date  of 
this  report 


5    Describe  event  or  problem 


6    Relevant  tests/laboratory  data,  including  dates 


7   Other  relevant  history,  including  preexisting  medical  conditions  (eg,  allergies, 
race,  pregnancy,  smoking  and  alcohol  use,  hepatic/renal  dysfunction,  etc.) 


Mall  to:     MEdWaTCI^I  or  FAX  to: 

5600  Fishers  Lane  1 -800-FDA-01 78 

Rockville,  MD  20852-9787 


C.  Suspect  medication(s) 


1 .  Name  (give  labeled  strength  &  mfr/labeler,  if  known) 

#1 


#2 


2    Dose,  frequency  &  route  used 


#1 


#2 


3.  Therapy  dates  (if  unknown,  give  duration) 

Irom/to  (or  best  eslimate) 
#1 


#2 


4.  Diagnosis  for  use  (indication) 

#1 


#2 


6-  Lot  #  (if  known) 

#1 


#2 


7.  Exp.  date  (if  known) 
#1 

#2 


9.  NDC  #  (for  product  problems  only) 


5    Event  abated  after  use 
stopped  or  dose  reduced 

#1  Dyes  Dno   D^g^fy"'' 


#2  Dyes  D  no    Dgg^Py"'' 


8    Event  reappeared  after 
reintroduction 

*1  Dyes  Dno   Dgg^Py"'' 


#2  Dyes  D  no   DS"'' 


10    Concomitant  medical  products  and  therapy  dates  (exclude  treatment  of  event) 


D.  Suspect  medical  device 


1    Brand  name 


2    Type  of  device 


3    Manufacturer  name  &  address 


6. 

model  #  _ 

catalog  # 

serial  # 

lot  * 

other  # 


4    Operator  of  device 

I    I  health  professional 
I    I  lay  user/patient 
n  other: 


5    Expiration  date 

(mo/day/yr| 


7    If  Implanted,  give  date 

(mo/day/yr) 


8.    If  explanted,  give  date 

(mo/day/yr) 


9    Device  available  for  evaluation?                (Do  not  send  to  FDA) 
I     I    yes  LJ  h°  LJ  returned  to  manufacturer  on 


frrro/riay/yr) 


10.  Concomitant  medical  products  and  therapy  dates  (exclude  treatment  of  event) 


E.    Reporter  (see  confidentiality  section  on  bacl<) 


1 .     Name  &  address 


phone  # 


2    Health  professional? 

□  yes       □    no 


3     Occupation 


5.     If  you  do  NOT  want  your  identity  disclosed  to 
the  manufacturer,  place  an  "  X  "  in  this  box.      Q 


4    Also  reported  to 

I     I      manufacturer 
I     I      user  facility 
I     I      distributor 


FDA  Form  3500  1/96) 


Submission  of  a  report  does  not  constitute  an  admission  that  medical  personnel  or  the  product  caused  or  contributed  to  th*-  event. 


ADVICE  ABOUT  VOLUNTARY  REPORTING 


Report  experiences  with: 

•  medications  (drugs  or  biologies) 

•  medical  devices  (including  in-vitro  diagnostics) 

•  special  nutritional  products  (dietary 
supplements,  medical  foods,  infant  formulas) 

•  other  products  regulated  by  FDA 

Report  SERIOUS  adverse  events.  An  event 
is  serious  when  the  patient  outcome  is: 

•  death 

•  life-threatening  (real  risk  of  dying) 

•  hospitalization  (initial  or  prolonged) 

•  disability  (significant,  persistent  or  permanent) 

•  congenital  anomaly 

•  required  intervention  to  prevent  permanent 
impairment  or  damage 

Report  even  if: 

•  you're  not  certain  the  product  caused  the 
event 

•  you  don't  have  all  the  details 

Report  product  problems  -  quality,  performance 
or  safety  concerns  such  as: 

•  suspected  contamination 

•  questionable  stability  '' 

•  defective  components 

•  poor  packaging  or  labeling 

•  therapeutic  failures 


How  to  report: 

•  just  fill  in  the  sections  that  apply  to  your  report 

•  use  section  C  for  all  products  except 
medical  devices 

•  attach  additional  blank  pages  if  needed 

•  use  a  separate  form  for  each  patient 

•  report  either  to  FDA  or  the  manufacturer 
(or  both) 


Important  numbers: 

•  1-800-FDA-0178 

•  1-800-FDA-7737 

•  1-800-FDA-1088 


•  1-800-822-7967 


to  FAX  report 

to  report  by  modem 

to  report  by  phone  or  for 

more  information 

for  a  VAERS  form 

for  vaccines 


If  your  report  involves  a  serious  adverse  event 
with  a  device  and  it  occurred  in  a  facility  outside  a  doc- 
tor's office,  that  facility  may  be  legally  required  to  report  to 
FDA  and/or  the  manufacturer.   Please  notify  the  person  in 
that  facility  who  would  handle  such  reporting. 

Confidentiality:  The  patient's  identity  is  held  in  strict 
confidence  by  FDA  and  protected  to  the  fullest  extent  of 
the  law.  The  reporter's  identity,  including  the  identity  of  a 
self-reporter,  may  be  shared  with  the  manufacturer  unless 
requested  otherwise.  However,  FDA  will  not  disclose  the 
reporter's  identity  in  response  to  a  request  from  the 
public,  pursuant  to  the  Freedom  of  Information  Act. 


The  public  reporting  burden  for  this  collection  of  information 
has  been  estimated  to  average  30  minutes  per  response, 
including  the  time  for  reviewing  instructions,  searching  exist- 
ing data  sources,  gathering  and  maintaining  the  data  needed, 
and  completing  and  reviewing  the  collection  of  information. 
Send  comments  regarding  this  burden  estimate  or  any  other 
aspect  of  this  collection  of  information,  including  suggestions 
for  reducing  this  burden  to: 


DHHS  Reports  Clearance  Office 
Paperworl<  Reduction  Project  (0910-0291) 
Hubert  H.  Humphrey  Building.  Room  531-H 
200  Independence  Avenue.  S.W. 
Washington,  DC  20201 


"An  agency  may  not  conduct  or  sponsor, 
and  a  person  is  not  required  to  respond  to. 
a  collection  of  information  unless  it  displays 
a  currently  valid  0MB  control  number." 


Please  do  NOT 
return  this  form 
to  either  of  these 
addresses. 


U.S.  DEPARTMENT  OF  HEALTH  AND  HUMAN  SERVICES 
Public  Health  Service  •  Food  and  Drug  Administration 


FDA  Form  3soo-back       PleasG  UsG  AdcJress  Provided  Below  -  Just  Fold  In  Thirds,  Tape  and  Mall 


Department  of 

Health  and  Human  Services 

Public  Health  Sen/ice 

Food  and  Drug  Administration 

Rockville,  MD  20857 

Official  Business 

Penalty  for  Private  Use  $300 


NO  POSTAGE 

NECESSARY 

IF  MAILED 

IN  THE 

UNITED  STATES 

OR  APO/FPO 


BUSINESS  REPLY  MAIL 

FIRST  CLASS  MAIL    PERMIT  NO.  946    ROCKVILLE,  MD 


POSTAGE  WILL  BE  PAID  BY  FOOD  AND  DRUG  ADMINISTRATION 


mec^J^Xtch 


The  FDA  Medical  Products  Reporting  Program 
Food  and  Drug  Administration 
5600  Fishers  Lane 
Rockville,  MD  20852-9787 


|,,l,lll...l.ilMliii.ilill>liilmll.il.lii.lMl.ll 


News  releases  about  new  products  and  services  will  be  considered  for  publication  in  this  section. 

There  is  no  charge  for  these  listings.  Send  descriptive  release  and  glossy  black  and  white  photographs 

to  RESPIRATORY  CARE,  New  Products  &  Services  Dept,  1 1030  Abies  Lane,  Dallas  TX  75229-4593. 

The  Reader  Service  Card  can  be  found  at  the  back  of  the  Journal. 


New  Products 
&  Services 


Aerosol  Valved  Holding  Chamber. 

Monaghan  Medical  Corporation  an- 
nounces it  has  received  Food  &  Drug 
Administration  clearance  to  market  its 
new  AeroChamber  PIustm  product  line. 
The  company  describes  the  devices  as 
high  performance  aerosol  valved  hold- 
ing chambers  (VHC).  According  to 
Monaghan,  the  AeroChamber  Plus 
VHC  is  a  significant  advancement  in  me- 
tered-dose-inhaler  aerosol  delivery  for 
COPD  and  asthma  patients.  The  company 
says  a  key  feature  of  the  new  devices  is  a 
"flowdynamic"  system  that  increases  the 
fine  particle  dose  of  MDIs  and  the  style 
for  children  (includes  a  mask)  features  a 
sturdier  design,  lower  inhalation  rate,  less 
dead  space,  and  an  improved  facial  seal 
on  the  mask.  For  more  information  from 
Monaghan  Medical,  circle  number  169  on 
the  reader  service  card  in  this  issue,  or 
send  your  request  electronically  via 
"Advertisers  Online"  at  http;//www. 
aarc.org/buyers_guide/ 


Equipment  Maintenance  Program.  The 

Services  and  Support  division  of 
Mallinckrodt  Inc's  Respiratory  Group  has 
introduced  a  program  they  say  will  help 
owners  and  operators  of  the  company's 
respiratory  equipment  specify  factory- 


built  parts  and  factory-authorized  service 
for  routine  preventive  maintenance  and 
inspection  services.  Mallinckrodt  says  the 
program  consists  of  two  gold-foil  stickers 
denoting  either  Mallinckrodt  Genuine 
Parts  or  Genuine  Service.  Company  press 
materials  say  the  stickers  designate  that 
replacement  parts  were  factory  made  and 
allow  Mallinckrodt  Customer  Support 
Engineers  or  factory  technicians  to  log 
product  services  performed  along  with 
the  date  of  service.  For  more  information 
from  Mallinckrodt,  circle  number  170  on 
the  reader  service  card  in  this  issue,  or 
send  your  request  electronically  via 
"Advertisers  Online"  at  http://www.aarc. 
org/buyers_guide/ 


raised  seven-inch  side  bolsters  and  Model 
2  with  a  gatch  relief  system  that  allows 
the  mattress  to  move  with  the  bed  frame. 
For  more  information  from  EHOB,  circle 
number  1 7 1  on  the  reader  service  card  in 
this  issue,  or  send  your  request  electroni- 
cally via  "Advertisers  Online"  at  http:// 
www.aarc.org/buyers_guide/ 


Mattress  Replacement  Systems.  EHOB 
Inc  introduces  its  Waffle®  Mattress 
Replacement  Systems,  Models  1  and  2. 
EHOB  describes  the  mattress  design  as 
air  over  foam  and  says  the  combination 
provides  protection  against  pressure  ul- 
cers. The  company  says  the  design  pro- 
vides tissue-unloading  static  air  directly 
under  the  patient  which  they  say  allows 
maximum  body-to-surface  contact. 
EHOB  says  the  mattresses  are  designed 
for  long-term  care  facilities,  Model  1  with 


Nebulizer.  Allied  Healthcare  Products  Inc 
has  introduced  its  new  Schuco  3000  nebu- 
lizer compressor.  The  company  describes 
the  unit  as  compact,  weighing  only  3.8 
pounds,  but  rugged  and  constructed  of 
damage-resistant  plastic.  Allied  says  the 
S3000  offers  recessed  tubing,  built-in  han- 
dle and  cord  storage,  and  a  filtration  system 
that  can  be  cleaned  and  reused.  And  ac- 
cording to  a  company  spokesperson,  the 
unit  operates  quietly  at  58dBA  and  pro- 
vides a  liter  flow  of  9  LPM  at  the  cup  with 
maximum  pressure  rating  of  35  PSL. 
Allied  says  each  S3000  comes  with  a  main- 
tenance-free compressor,  nebulizer,  tubing, 
mouthpiece,  and  tee.  For  more  information 
from  Allied  Healthcare  Products,  circle 
number  172  on  the  reader  service  card  in 
this  issue,  or  send  your  request  electroni- 
cally via  "Advertisers  Online"  at  http:// 
www.aarc.org/buyers_guide/ 


RESPIRATORY  CARE  •  DECEMBER  1999  VOL  44  NO  12 


153? 


Not-for-profit  organizations  are  offered  a  free  advertisement  of  up  to  eight  lines  to  appear,  on  a  space-available 

basis,  in  Calendar  of  Events  in  RESPIRATORY  CARE.  Ads  for  other  meetings  are  priced  at  $5.50  per  line  and  require 

an  insertion  order.  Deadline  is  the  20th  of  the  month  two  months  preceding  the  month  in  which  you  wish  the  ad  to  run. 

Submit  copy  and  insertion  orders  to  Calendar  of  Events,  RESPIRATORY  CARE,  1 1030  Abies  Lane,  Dallas  TX  75229-4593. 


Calendar 
of  Events 


AARC  &  AFFILIATES 

December  13-16 — Las  Vegas, 

Nevada 

The  AARC's  45th  International 
Respiratory  Congress  is  scheduled 
for  Dec.  13-16  (Monday  through 
Thursday)  at  the  Las  Vegas 
Convention  Center.  Sessions 
appealing  to  all  levels  of  health 
care  providers  will  be  offered,  with 
CRCE  credit  available.  Exhibits  by 
international  manufacturers  of 
cardiopulmonary  equipment  will 
be  featured.  See  the  AARC  web 
site  for  additional  information: 
www.aarc.org. 

January  21, 2000 — Bloomington, 
Minnesota 

The  Minnesota  Society  for 
Respiratory  Care  host  their 
Frostbite  Forum  —  "Light  a  Fire" 
—  at  the  Doubletree  Inn.  Five 
CRCEs  have  been  requested. 
Contact:  For  more  information, 
contact  Laurie  Tomaszewski  at 
(651)  232-1922,  Carolyn  Dunow 
at  dunowc@fhpcare.com,  or 
Carl  Mottram  at  mottram. 
carI@mayo.edu. 

March  15-17,  imi—Lake  Tahoe, 
Nevada 

The  Greater  Bay  Area  Chapter  of 
the  California  Society  for 
Respiratory  Care  host  their  2 1  st 
annual  conference  at  Caesars 
Lake  Tahoe.  "Tahoe  2000"  will 
offer  1 2  hours  of  continuing 
education  credit. 
Contact:  For  more  information, 
call  (925)  866-6643  or  access 
their  web  site  at  www.csrc.org. 


May  19, 2000— Brainerd 
Minnesota 

The  Minnesota  Society  for 
Respiratory  Care  host  their  Spring 
Fling  —  "Rev  It  Up"  at  the 
Breezy  Point  Resort.  Five  CRCEs 
will  be  requested. 
Contact:  For  more  information, 
contact  Laurie  Tomaszewski  at 
(651)  232-1922,  Carolyn  Dunow 
at  dunowc@fhpcare.com,  or 
Carl  Mottram  at 
mottram.carl  @  mayo.edu. 

Other  Meetings 

February  27-March  2 — Keystone 
Resorts,  Colorado 

The  16th  Annual  Children's 
National  Medical  Center 
Symposium  on  ECMO  and 
Advanced  Therapies  for 
Respiratory  Failure  will  be  held  at 
Keystone  Resorts.  Topics  include 
new  uses  for  ECMO, 
hyperthermia  for  cancer  therapy, 
hypothermia  for  neuroprotection, 
and  extracorporeal  CPR. 
Contact:  Dr.  Billie  Lou  Short  at 
(202)  884-50 1 8  or  bshort@ 
cnmc.org. 

March  27-30, 2000— Clearwater 
Beach,  Florida 

All  Children's  Hospital  will  host 
a  neonatal/pediatric  transport 
conference,  "Leading  the  Way  — 
Staying  Patient  Focused,"  at  the 
Hilton  Clearwater  Beach  Resort. 
Continuing  education  hours 
available  for  RNs  and  RTs. 
Contact:  Connie  Spadaccino  at 
(800)  456-4543,  ext.  4240,  or  fax 
(727)  892-4399. 


April  1-7,  2000— Miami,  Florida 
Miami  Children's  Hospital  and  the 
Ventilation  Assisted  Children's 
Center  (VACC)  are  hosting  their 
annual  camp  for  ventilation- 
assisted  children  and  their  families. 
The  campsite  is  A.D.  Barnes  Park, 
a  62-acre  park  located  two  miles 
from  Miami  Children's  Hospital. 
Facilities  include  an  air- 
conditioned  lodge,  two  air- 
conditioned  bunkhouses,  and 
wheelchair-accessible  swimming 
pool,  playground,  and  nature  trail. 
The  VACC  Camp  treats  families 
with  children  dependent  on 
oxygen,  a  tracheostomy,  ventilator, 
CPAP,  or  bi-level  PAP  to  a  week 
of  fun  and  adventure  in  the 
company  of  their  peers. 
Contact:  If  you  know  of  eligible, 
interested  families,  have  them 
contact  Camp  Director  Dr.  Moises 
Simpeer  or  Bela  Floretin  at  (305) 
662-8380,  ext.  4610,  or  (305)  662- 
8222.  Applications  will  be 
accepted  through  Jan.  15,  2000. 

May  19-21, 2000— Atlanta,  Georgia 

Children's  Healthcare  of  Atlanta- 
Egleston  will  sponsor  "Moving 
ECMO  into  the  New  Millennium" 
—  SEECMO  2000,  the  10th 
Annual  Southeastern  ECMO 
Conference,  at  the  Grand  Hyatt 
Buckhead.  Presentations  will 
cover  adult  ECMO,  ECMO  flow 
direction,  CVVH  techniques,  and 
hands-on  water  drills. 
Contact:  Micheal  Heard,  RN,  at 
(404)  3 15-2593  or  micheal. 
heard@choa.org. 


1534 


Respiratory  Care  •  December  1999  Vol  44  No  12 


Notices 


Notices  ot  compcliiions,  scholarships,  tellowships.  examination  dates,  new  educaiioiial  progrunis. 

and  the  hke  wiW  be  Hsted  here  Iree  ot  charge.  Items  lor  the  Notices  section  must  leach  the  Journal  60  days 

betore  the  desired  month  ot  pubhcation  (January  I  tor  the  March  issue.  February  I  tor  the  April  issue,  etc).  Include  all 

pertinent  inlormalion  and  mail  notices  to  RtSPIRA  lOkY  CARb  Notices  Dept,  1 IU3U  Abies  Lane,  Dallas  IX  75229-4593. 


Sc^tduUct  Pto^fe4.dO'%'4'  ^o-undd  2000 

Pulmonary  Rehabilitation:  What  You  Need  to  Know —  Julien  M  Roy 
BA  RRT;  Host,  Richard  Branson  BA  RRT~Video  March  7;  Audio  April  4 

Pediatric  Asthma  in  the  ER— Tim  Myers  BS  RR  I";  Host.  Richard  Bran- 
son BA  RRT— Video  March  28;  Audio  April  18 

Drugs,  Medications  and  Delivery  Devices  of  Importance  in  Respiratory 

Care— Jim  Fink  MS  RRT:  Host,  David  Pierson  MD— Video  April  25; 
Audio  May  16 

Cost  Effective  Respiratory  Care:  You've  Got  to  Change — Kevin  Shrake 
MA  RRT  FACHE;  Host,  Sam  P  Giordano  MBA  RRT— Video  23;Audio 
June  20 

Pediatric  Ventilation:  Kids  Are  Different — Mark  Hculitt  MD;  Host, 
Richard  Branson  BA  RRT — Video  25;  Audio  August  15 

What  Matters  in  Respiratory  Monitoring:  What  Goes  and  What 

Stays— Dean  Hess  PhD  RRT  FAARC;  Host,  Richard  Branson  BA  RR T— 
Video  August  22;  Audio  September  26 

Managing  Asthma:  An  Update — Fatti  Joyner  RRT  COM;  Host,  Mari 
Jones  MSN  RN  RRT— Video  September  19;  Audio  October  17 

Routine  Pulmonary  Function  Testing:  Doing  it  Right — Carl  D  Motlram 
RRT  RPFT;  Host,  David  Pierson  MD— Video  November  7;  Audio 
December  5 


fel  Helpful  UJeb|Sjtes 


American  Association  for  Respiratory  Care 

http://www.aarc.org 

—  Current  job  listings 

—  American  Respiratory  Care  Foundation 
fellowships,  grants,  &  awards 

—  Clinical  Practice  Guidelines 

National  Board  for  Respiratory  Care 

http://www.nbrc.org 

Respiratory  Care  online 

http://www.rcjournal.com 

—  1 998  Subject  and  Author  Indexes 

—  Contact  the  editorial  staff 

Astlima  iVianagement 
Model  System 

http://www.nhlbi.nih.gov 

Keys  to  Professional  Excellence 

http://www.aarc.org/keys/ 


The  National  Board  for  Respiratory  Care — 2000  Examination  Dates  and  Fees 


Examination 


CRT 


Applications  Accepted/ 
Testing  Available 

Dec  1,  1999 
Jan  10,2000 


Examination  Fees 


$190  (new  applicant) 
$150(reapplicant) 


Perinatal/Pediatric 


CPR 


Dec  1,  1999 
Jan  10.2000 

Jan  1 .  2000 
Feb  1,2000 


$250  (new  applicant) 
$220(reapplicant) 

$200  (new  applicant) 
$170  (reapplicani) 


RPFT 


Jan  1,2000 
Feb  1,2000 


$250  (new  applicant) 
$170(reapplicant) 


RRT 

(Written  &  CSE) 


Feb  1,2000 
Apr  1,2000 


$190  (new  -  written  only) 
$200  (new  -  CSE  only) 
$390  (new  -  both) 


For  information  about  other  services  or  fees,  write  to  the  National  Board  for  Respiratory  Care. 
83 10  Nieman  Road.  Lenexa  K.S  66214,  or  call  (913)  599-4200,  FAX  (913)  541-OI56,or  e-mail:  nbrc-info(a> iibrc.org 


Respiratory  Care  •  December  1999  vol  44  No  12 


1535 


Authors 
in  This  Issue 


Aboussouan,  Loutfi  S   1491 

Afari,  Niloofar    1452 

Bamhart,  Scott    1452 

Blonshine,  Susan    1458 

Buchwald,  Dedra  S     1452 

Cairo,  J  M 1494 

Caras,  William  E    1465 

Carella,  Michael  J     1458 

Chatbum,  Robert  L 1496 

Dillard,  Thomas    1465 

Donner,  Claudio  F    1495 

Eckert,  Brenton 1493 

Foss,  Scott  A 1474 

Gera,  C  Mohan     1458 

Gossain,  Ved  V    1458 

Gudjonsdottir,  Marta    1495 

Helms,  Michael    1447 


Hyde,  Keith    1494 

Keppel,  Jean  W    1474 

Laskowski,  Daniel    1493 

Maclntyre,  Neil  R     1447 

Maunder,  Richard  J    1494 

McCarthy,  Kevin    1486,  1493 

Mehta,  Atul  C     1489 

Pierson,  David  J   1496 

Reasor,  Tammy    1465 

Ropp,  Brad 1458 

Sahn,  Steven  A     1447 

Seshadri,  Niranjan    1489 

Schmaling,  Karen  B    1452 

Schmidt,  Gregory   1447 

Stoller,  James  K    1486,  1493 

Winter,  Michael  G    1465 

Wunderink,  Richard    1447 


Advertisers 
in  This  Issue 


To  advertise  in  RESPIRATORY  CARE,  contact  Tim  Goldsbury,  20  Tradewinds  Circle,  Tequesta  FL  33469 
at  (561)  745-6793,  Fax  (561)  745-6795,  e-mail:  goldsbury@aarc.org,  for  rates  and  media  kits.  For  recruitment/ 
classified  advertising  contact  Beth  Binkley,  Marketing  Assistant  for  RESPIRATORY  CARE,  at  (972)  243-2272, 
Fax  (972)  484-6010.  Dale  Grimths  is  the  Marketing  Director  for  RESPIRATORY  CARE. 


Amethyst  Research 1433 

Circle  Info  Card  No.  1 1 1  SEE  AD 

Blake  Medical,  Inc 1445 

Circle  Info  Card  No.  1 2 1  Call  (8(X))  989-4553 

DEY    Cover  2 

Circle  Info  Card  No.  1 33  Call  (800)  527-4278 

DHD Cover  4 

Circle  Info  Card  No.  106  Call  (800)  847-8000 

Drager,  Inc 1437 

Circle  Info  Card  No.  123  Call  (800)  437-2437 

Hans  Rudolph,  Inc 1419 

Circle  Info  Card  No.  120  Call  (800)  456-6695 

Hospitalhub.com 1417 

Circle  Info  Card  No.  105  Call  (888)  562-4357 

Hudson  RCl 1427 

Circle  Info  Card  No.  108  Call  (800)  848-3766 

Kaiser  Permanente 1443 

Circle  Info  Card  No.  1 1 5  Call  (800)  33 1  -3976 

Mallinckrodt,  Inc Cover  3 

Circle  Info  Card  No.  1 25  Call  (800)  635-5267 

COPYRIGHT  INFORMATION.  RESPIRATORY  CARE  is  copyrighted  by 
Daedalus  Enterprises  Inc.  Reproduction  in  whole  or  in  part  without  the  express 
written  pennission  of  Daedalus  Enterprises  Inc  is  prohibited.  Permission  to 
photocopy  a  single  article  in  this  Journal  for  noncommercial  purposes  of 
scientific  or  educational  advancement  is  granted.  Permission  for  multiple 
photocopies  and  copies  for  commercial  purposes  must  be  requested  in  writ- 
ing, via  e-mail  (rcjournal@aarc.org),  or  telephone  and  approved  by  RESPI- 
RATORY Care.  Anyone  may,  without  permission,  quote  up  to  500  words  of 
material  in  this  journal  provided  the  quotation  is  for  noncommercial  use  and 
RESPIRATORY  CARE  is  credited.  Longer  quotation  requires  written  ap- 
proval by  the  author  and  publisher.  Single  reprints  are  available  only  from  the 
authors.  Reprints  for  commercial  use  may  be  purchased  from  Daedalus  En- 
terprises Inc.  For  more  information  and  prices  call  (972)  243-2272. 

DISCLAIMER.  The  opinions  expressed  in  any  article  or  editorial  are  those 
of  the  author  and  do  not  necessarily  reflect  the  views  of  the  Editors,  the 
American  Association  for  Respiratory  Care  (AARC),  or  Daedalus  Enter- 
prises Inc.  Neither  are  the  Editors,  the  AARC,  or  the  Publisher  responsible 
for  the  consequences  of  the  clinical  applications  or  use  of  any  methods  or  de- 
vices described  in  any  article  or  advertisement. 

SUBSCRIPTION  Rates.  Individual  subscription  rates  are  $75  per  year 
(12  issues),  $145  for  2  years,  and  $215  for  3  years  in  the  US  and  Puerto 
Rico.  Rates  are  S90  per  year,  $  1 75  for  2  years,  and  $260  for  3  years  in  all  other 
countries  (add  $94  per  year  for  air  mail).  Single  copies  when  available  cost 
S7;  add  $9  for  air  mail  postage  to  overseas  countries.  Checks  should  be 


Masimo 1410 

Circle  Info  Card  No.  140  Call  (877)  4-MASIMO 

Maxtec 1425 

Circle  Info  Card  No.  1 29  Call  (800)  748-5355 

Monaghan  Medical 1421 

Circle  Info  Card  No.  1 3 1  Call  (800)  833-9653 

Monaghan  Medical 1439 

Circle  Info  Card  No.  1 27  Call  (800)  833-9653 

Novametrix 1414 

Circle  Info  Card  No.  126  Call  (800)  243-3444 

Praxair 1412 

Circle  Info  Card  No.  109  Call  (800)  299-7977 

Rush-Presbyterian 1441 

Circle  Info  Card  No.  103  SEE  AD 

Sims-Portex  Inc 1435 

Circle  Info  Card  No.  1 30  Call  (800)  258-536 1 

Westmed  Inc 1423 

Circle  Info  Card  No.  104  Call  (800)  724-2328 


made  payable  to  RESPIRATORY  CARE  and  sent  to  the  subscription  office  at 
1 1030  Abies  Lane,  Dallas  TX  75229-4593,  or  call  (972)  243-2272. 

SUBSCRIPTION  RATES  FOR  ASSOCIATIONS.  Basic  annual  subscrip- 
tions are  offered  to  members  of  associations  according  to  their  member- 
ship enrollment:  101-500  members  =  $13.50/year;  501-1,500  =  S13/year; 
1,500-10,000  =  $12.50/year;  more  than  10,000  =  $1 1.50/year.  Individual 
subscriptions  ar  available  at  these  rates:  $75/year  (12  issues  in  the  United  States 
or  Puerto  Rico;  $90/year  in  other  countries.  For  information,  contact  Ray 
Masferrer  at  (972)  243-2272. 

CHANGE  OF  ADDRESS.  Notify  the  AARC  at  (972)  243-2272  as  soon  as  pos- 
sible of  any  change  in  address.  Note  the  subscription  number  (from  the 
mailing  label)  and  your  name,  old  address,  and  new  address.  Allow  6 
weeks  for  the  change.  To  avoid  charges  for  replacement  copies  of  missed  is- 
sues, requests  must  be  made  within  60  days  in  the  US  and  90  days  in  other 
countries. 

MANUSCRIPTS.  The  Journal  publishes  clinical  studies,  method/device 
evaluations,  reviews,  and  other  materials  related  to  cardiopulmonary  med- 
icine and  research.  Manuscripts  may  be  submitted  to  the  Editorial  Office,  RES- 
PIRATORY CARE,  600  Ninth  Avenue,  Suite  702,  Seattle  WA  98104.  In- 
structions for  authors  are  printed  in  every  issue.  An  expanded  version  of 
the  Instructions  is  available  from  the  editorial  office. 


Copyright  ©  1999,  by  Daedalus  Enterprises  Inc. 


1536 


RESPIRATORY  CARE  •  DECEMBER  1999  VOL  44  NO  12 


Respiratory  Care 
Subscription  Form 

U^  SuiMcriptlans   Subicriptiam  Outtkle  U^ 


1  YR 
(12isiu«) 

ZYRS 
(24  Issues) 

3YRS 
(J6bsues) 


D»7S 

D»145 

a»215 


D»90 

n'175 

n'260 


Respihatory  Care  is  the  most  highly 
regarded  peer-reviewed  scientific 
publication  for  the  Clinician 
participating  in  the  evaluation 
arid  care  of  patients  with 
cardiopulmonary  problems. 
Please  print;  incomplete  forms 
wilt  not  be  processed.  For  faster 
service,  fax  to  (972)484-2720 

Enclosed  Is  a  check 
In  the  amount  of 


PON'T 


Chargetomy: 

n  Mastercard 
D  Visa 
O  Bill  Me 


Stgrtature 


Credit  Card  Number 


I  our  song 


Facility  Name 


City 


Tetephonc 


Zip  Code  Country 

RE/PIRA[rORy  CARE 


Product 
information 

For  AAftC  memberihip  inlormatJOfi,  cirtlc  10 

101    102  103   104   105  106 

119    120    121    122    123  124 

337   138  139   140   141  142 

155    156   157    158    159  160 

m  174  175   176  177  178 

191    192    193    194    195  196 


To  receive  information  on  the  products 
and  services  mentioned  in  this  issue, 
circle  the  corresponding  category 
number  or  individual  manufacturer's 
number.  Fill  in  your  name  and  address 
and  mail  this  postage-paid  card. 
Information  will  be  sent  directly  to  you 
from  the  manufacturer.  Please  print; 
incomplete  forms  will  not  be 
processed.  For  faster  service,  fax  to 
(609)786-4415 

i    Fot  tosPHwio*'  Ca»e  subscription  intonnition,  circle  102. 

107  108  109  110  111  112  113  114    115  116 

125  126  127  128  129  130  131  132    133  134 

143  144  145  146  147  148  149  150   151  152 

161  162  163  164  165  166  167  168    169  170 

179  180  181  182  183  184  185  186  187  188 

197    198    199   200 
ncaM  drdc  no  man  thwi  IS  Ittnn. 


Narm 

Title 

Facility  Name 

Address 

City 

State 

Zip  Code 

Country 

m 


117  118 
135  136 
153  154 
171  172 
189  190 


1    TYP£  Of  INSTTTUnON 

6   □  Diagnostics/ 

OR  PRACTICE 

Pulmonary  Function 

1    D  Hospital 

7   D  Management 

2   n  Skilled  Nursing 

8  n  Home  Care 

Facility 

9  D  Rehabilitation 

3  D  Subacute  Care  Facility 

10  D  Education 

4   n  Home  Care  Practice 

5   D  School 

IV      POSITION 

6   n  Distributor 

A  n  Department  Head 

B  n  Chief  Therapist 

II   MPARTMENTT 

C  D  Supervisor 

A  D  Respiratory  Care 

D  D  Staff  Therapist/ 

B   D  Cardiopulmonary 

Technician 

C  n  Subacute  Care 

E    D  Medical  Director 

D  D  Home  Care 

F    a  Educator/Instructor 

C  D  Sales 

HI  SPECIALTY 

H  D  Other  (please  specify) 

1    D  Clinician 

2   D  Perinatal/  Pediatrics 

3   D  Critical  Care 

V  AREVOOANAARC 

4   D  Research 

MEMBER? 

5   D  Subacute  Care 

1    D  Yes    2    D  No 

led  Signal  Processing  and 
iging  motion  conditions.* 

Je  know  that  reality  by  heart. 
t*  XL,  the  N-395  cuts  through 
les.  Accurate  readings,  fewer 
music  to  your  ears.  To  learn 
r — Oximetry  You  Can  Trust. 


ne  N-395  produces  a  20%  improvement  in 


Telephone 


DFrDIDATODU    rADC 


Authors 
in  This  Issue 

Aboussouan,  Loutfi  S   

Afari,  Niloofar    

Bamhart,  Scott   

Blonshine,  Susan    

Buchwald,  Dedra  S     

Cairo,  J  M 

Caras,  William  E    

Carella,  Michael  J     

Chatbum,  Robert  L 

Dillard,  Thomas    

Donner,  Claudio  F    

Eckert,  Brenton 

Foss,  Scott  A 

Gera,  C  Mohan  .  .  . 
Gossain,  Ved  V  ... 
Gudjonsdottir,  Marta 
Helms,  Michael    .  .  . 

Adverti! 
in  This  Is 

Amethyst  Research  . 

Circle  Info  Card  No.  1 1 

Blake  Medical,  Inc. .  . 

Circle  Info  Card  No.  12 

DEY    

Circle  Info  Card  No.  13 

DHD 

Circle  Info  Card  No.  10 

Drager,  Inc 

Circle  Info  Card  No.  12 

Hans  Rudolph,  Inc.  .  . 

Circle  Info  Card  No.  12 

Hospitalhub.com  .... 

Circle  Info  Card  No.  10 

Hudson  RCI 

Circle  Info  Card  No.  10 

Kaiser  Permanente.  .  . 

Circle  Info  Card  No.  1 1 

Mallinckrodt,  Inc. .  .  . 

Circle  Info  Card  No.  12 

COPYRIGHT  Inform, 

Daedalus  Enterprises  Inc. 
written  permission  of  Da 
photocopy  a  single  artic 
scientific  or  educational 
photocopies  and  copies  f 
ing,  via  e-mail  (rcjoumal 
RATORY  Care.  Anyone 
material  in  this  journal  pr 
Respiratory  Care  is 
proval  by  the  author  and  p 
authors.  Reprints  for  con- 
terprises  Inc.  For  more  in 

Disclaimer.  The  opin 
of  the  author  and  do  noi 
American  Association  ft 
prises  Inc.  Neither  are  th 
for  the  consequences  of  tf 
vices  described  in  any  ar 

SUBSCRIPTION  RATE! 

(12  issues),  $145  for  2  > 
Rico.  Rates  are  $90  per  ye 
countries  (add  $94  per  ye 
$7;  add  $9  for  air  mail 


.1491  Hyde,  Keith    1494 

.1452  Keppel,  Jean  W    1474 

.1452  Laskowski,  Daniel    1493 

.1458  Maclntyre,  Neil  R     1447 

.1452  Maunder,  Richard  J    1494 

.1494  McCarthy,  Kevin    1486,  1493 

.1465  Mehta,  Atul  C     1489 

.1458  Pierson,  David  J   1496 

.1496  Reasor,  Tammy    1465 

.1465  Ropp,  Brad  1458 

.1495  Sahn,  Steven  A     1447 

.1493  Seshadri,  Niranjan    1489 

.1474  Schmaling,  Karen  B 1452 


BUSINESS  REPLY  MAIL 

FIRST-CLASS  MAIL  PERMIT  NO.  2480  Dallas.TX 


NO  POSTAGE 

NECESSARY 

IF  MAILED 

IN  THE 

UNITED  STATES 


POSTAGE  WILL  BE  PAID  BY  ADDRESSEE 

AARC  Subscriptions 

ATTN:  Beth  Binkley 
PO  BOX  29686 
Dallas  TX  75229-9691 


II. ,.1,1.1., .1.1, .1.11. 1. .1.1.. .11. .1.1 nil... I 


BUSINESS  REPLY  MAIL 

FIRST-CLASS  MAIL  PERMIT  NO.  881  Riverton,  NJ 


NO  POSTAGE 

NECESSARY 

IF  MAILED 

IN  THE 

UNITED  STATES 


POSTAGE  WILL  BE  PAID  BY  ADDRESSEE 


AARC  Publications 

PO  BOX  11605 
Riverton  NJ  08076-7205 


1536 


..,l„l,ll...l..,l,ll..l...l..l.lll....l.l..l.lil 


:^s*B.t*>^; 


"'M. 


"">'^IT^.. 


Oil 


w. 


hey,  they're  playing  our  song 


The  new  Nellcor*  N-395  Pulse  Oximeter  with  Oxismart*  XL  Advanced  Signal  Processing  and 
SatSeconds'"  Revolutionary  Alarm  Management  reads  through  challenging  motion  conditions.* 

It's  a  familiar  tune — patient  movement,  low  perfusion,  low  signal  conditions.  We  know  that  reality  by  heart. 
After  all,  it's  an  environment  where  the  N-395  really  performs.  With  Oxismart*  XL,  the  N-395  cuts  through 
non-specific  noise  to  find  the  pulse  and  track  true  Sp02  and  pulse  rate  values.  Accurate  readings,  fewer 
nuisance  alarms.  The  Nellcor  N-395.  In  today's  clinical  environment,  it'll  be  music  to  your  ears.  To  learn 
more,  contact  your  Mallinckrodt  representative  or  call  1.800.635.5267.  Nellcor— Oximetry  You  Can  Trust. 


/\AvA^ 


N-J95  Pulse  Oximeter 

With  Oxismart  XL  and  SatSeconds 


Q 


ALLINCKRODT 


Circle  125  on  product  Info  card 
Visit  Booth  605  In  Las  Vegas 

"Challenging  motion"  is  of  a  nature  and  of  sufficient  magnitude  to  cause  the  N- 3000  to  be  in  pulse  search  at  least  40%  of  the  time.  Under  "challenging  motion"  conditions,  the  N-395  produces  a  20%  improvement  in 
motion  performance  compared  to  the  N-3000.  Motion  performance  claims  verified  for  adult  and  neonatal  patients  using  D-25  and  N-25  sensors. 


One. 


For  all. 


'If 


1 


Positive  Expiratory  Pressure  Therapy  System 


Patient-administered 
secretion  clearance 
and  reversal  of 
atelectasis. 


iiultaneous  aerosol 
d  1  ug  delivery  with 
nebuHzer  while 
performing  therapy 
for  secretion  clearance 
and  atelectasis. 


Simultaneous  aerosol 
drug  delivery  with 
MDT  spacer  while 
performing  therapy 
for  secretion  clearance 
and  atelectasis. 


The  proven  choice  for  secretion  clearance  and  reversal  of  atelectasis.' 


Today,  more  patients  than  ever  can  benefit  from  TheraPEP, 
the  first  system  designed  specifically  for  positive  expiratory 
pressure  therapy.  Now  indicated  for  use  with  simultaneous 
aerosol  drug  delivery,  TheraPEP  can  help  virtually  any 
patient  with  secretory  problems  mobilize  secretions  easily, 
conveniently  and  cost-effectively. 

Unlike  CPT,  PEP  therapy  can  be  self-administered  in  any 
setting,  helping  patients  maintain  an  effective  continuum  of 
care  outside  the  hospital.  TheraPEP  may  reduce  the  need  for 
postural  drainage  and  percussion,  and  can  be  performed  in 
less  than  half  the  time  of  a  conventional  CPT  session.^  This 
offers  significant  time  savings  for  both  patients  and  clinicians. 

1  Mcllwaine,  P.M.,  Wong,  L.T.,  Peacock,  D.,  Davidson,  G.F.  "Long-term 
comparative  trial  of  conventional  postural  drainage  and  percussion  versus 
positive  expiratory  pressure  physiotherapy  in  the  treatment  of  cystic  fibrosis." 
The  journal  of  Pediatrics,  Octob>er  1997. 

7.  Protocol  of  the  Month,  University  of  Pittsburgh  Medical  Center,  Department  of 
^^espiratory  Care.  AARC  Times,  May  1997. 


TheraPEP  is  even  more  efficient  when  used  with  a  nebulizer 
or  MDI  spacer.  The  patient  can  receive  aerosolized  medication, 
and  perform  therapy  for  secretion  clearance  and  atelectasis, 
in  the  time  of  one  treatment.  PEP  therapy  may  also  optimize 
delivery  of  bronchodilators  in  patients  receiving  bronchial 
hygiene  therapy.*  No  other  secretion  clearance  device  offers 
you  a  better  combination  of  therapy,  flexibility  and  efficiency. 
For  more  information,  call  DHD  Healthcare  toll-free  today: 


1-800-847-8000. 


O 


DHD 

Healthcare 

Innovations  for  respiratory  care 


3  Mahlmeister  MJ,  Fink  JB,  Hoffman  GL,  Fifer  LF,  "Positive-expiratory-pressure 
mask  therapy:  Theoretical  and  Practical  Considerations  and  a  Review  of  the 
Literature",  Respiratory  Care,  1991;  36:1218-1230. 

4  "AARC  Clinical  Practice  Guideline:  'Use  of  Positive  Airway  Pressure  Adjuncts 
to  Bronchial  Hygiene  Therapy',"  Rcspirafory  Care,  1993;  38:516-521. 


125  Rasbach  Street  Canastota,  NY  13032  USA  • 

TheraPEP  is  a  registered  trademark  of  DHD  Healthcare  Corporation. 


(315)  697-2221 


FAX:  (315)  697-5191    •  www.dhd.com 

®  1999  DHD  Healthcare  Corporation 


Circle  106  on  product  info  card