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

MAY 2001

VOLUME 46

NUMBER 5

ISSN 00201324RECACP

A MONTHLY SCIENCE JOURNAL
46TH YEAR— ESTABLISHED 1956

2001 Open Forum

Call for Abstracts

Early Deadline May 31

Final Deadline July 17

ORIGINAL CONTRIBUTIONS

Effect of Inner Cannula Removal on Work of
Breathing Imposed by Tracheostomy Tubes

Electrical Stimulation for Swallowing Disorders
Caused by Stroke

SPECIAL ARTICLES

Physicians Working with Respiratory Therapists to
Optimally Meet Respiratory Home Care Needs

GUIDELINES. RECOMMENDATIONS,
& STATEMENTS

AARC Clinical Practice Guidelines: 2001 Revisions &
Updates

Blood Gas Analysis and Hemoximetry

Body Plethysmography

Exercise Testing for Evaluation of Hypoxemia
and/or Desaturation

Methacholine Challenge Testing

Static Lung Volumes

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PDPs in your facility and an overview of PDPs and operational costs.

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NEW - Pediatric Metered Dose Inhaler Protocol (Ages 512)
NEW - Simple Weaning Protocol for Pediatrics

NEW - Introduction Contains an Overview of PDPs

and Operational Costs
Oxygen
Oximetry

Prophylaxis for Pulmonary Complications (IS)
Secretion Management (CPT)
Secretion Management for Artificial Airways
Percussionaire
Autogenic Drainage (AD)
Positive Expiratory Pressure (PEP)
Flutter Valve
ThAIRapy Vest
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Small Volume Nebulizer (SVN)

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Acute Maximum Dosage

Intermittent Positive Pressure Breathing (IPPB)

Thoracoscopy

Extubation

Post-Op Laparotomy

Prophylaxis Protocol Addendum For Rib
Fractures/Chest Trauma

Metered Dose Inhaler for Ventilated Patients

Secretion Management for Ventilated Patients

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Volume Reduction Lung Surgery Protocol (VRLS)

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MAY 2001 / VOLUME 46 / NUMBER 5

FOR INFORMATION.
CONTACT:

AARC Membership
or Other AARC Services

AiiieiiLdii Asbucialion tor Respira-

torv Care

11030 Abies Ln

Daiias TX 75229-4593

(972) 243-2272 • Fax (972) 484-2720

http://www.aarc.org

Therapist Registration or
Technician Certification

National Board for Respiratory

Care

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LenexaKS 66214

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

htlp'/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

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dation

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Dallas TX 75229-4593
(972) 243-2272 • Fax (972) 484-2720

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Director of Govt Affairs

Jill Eicher

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Alexandria VA 22314

(703) 548-8538 Fax (703) 548-8499

eicher@aarc.org

Director of State Govt Affairs
Cheryl West IVIHA
8630 Braeswood Ft. #2
Colorado Springs. CO 80920
(719) 535-9970 west@aarc.org

RE/PIRATORy
C&RE

RESPIRATORY CARE (ISSN 0020-1324, USPS 0489-
IVO) is published tnonlhly by Daedalus Enterprises Inc. at
1 10.10 Abies I jne. DjIIjs TX 75229-4593. for the Amer-
ican Association tor Respiratory Care. One volume is
published per year beginning each January. Subscription
rales are S75 per year in the US: S90 in all other countries
(for airmail, add S94).

The conienis of the Journal arc indexed in Index
MedicusMEDLWE. Hospital and Health Administration
Index, Cumulative Index to Nursing and Allied Health
Lilerdturc, EMBASE/Excrpla Medica. and RNdex Li-
brary Edition. Abridged versions of RESPIRATORY
Care are also published in Italian. French, and Japanese,
with fwrmission from Daedalus Enterprises 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 Unc. Dallas TX 75229-4593.

©^rinted on acid-free paper.

Printed in the United States of America

ORIGINAL CONTRIBUTIONS

lilTcct 1)1' Inner Cannula Removal on iIk- V\ ork n\ Bivaihini;
Imposed hy Tracheostomy Tubes: A Bench Study
In i<m\ i'muiii. iimoih\ II t>ii'l Hull. Cyiuli Gcfifiiluiiner, Selli Izenberg,
iiiitl Panduruiift Kulkarni— Mobile, Alabama

Electrical Stunulation for Swallowing Disorders Caused by Stroke

In Many L Freed — Cleveland, Ohiii.

Leonard Freed — Honolulu. Hawaii,

Robert L Clialbiirn ami .Michael Christian—Cleveland. Ohio

460

466

SPECIAL ARTICLES

Partnering for Optimal Respiratory Home Care: Physicians Working

with Respiratory Therapists to Optimally Meet Respiratory Home Care Needs

h\ Circf; Spnilt—Kirksville. Missimri. and Thomas I. Petty — Denver. Colorado

475

LETTERS

Lung Collapse During Low Tidal Volume Ventilation in Acute

Respiratory Distress Syndrome

by Jeffrey M Huynes — Nashua, New Hampshire

response by Richard H Kallel — San Francisco. California

BOOKS, FILMS, TAPES, & SOFTWARE

Irwin and Rippe's Intensive Care Medicine. 4th ed (2 vol)
(Irwin RS. Cerra FB. Rippe JM, editors)

reviewed by Benjamin D Medoff— Boston. Massachusetts

Procedures and Techniques in Intensive Care Medicine, 2nd cd
(Irwin RS. Rippe .IM. Cerra FB. Curley FJ. Heard SO. editors)
reviewed by Geiniic N Giacoppe— Tacoma. Washini;ton

Handbook of Pediatric Intensive Care, 3rd ed (Rogers MC,
Helfaer MA, editors)

reviewed by Heidi J Dalton — Washinalon DC

Drugs in Anaesthetic and Intensive Care Practice. 8th ed (Vickers MD,
Morgan M. Spencer PSJ. Read MS)

reviewed hy Rick .Sai-Chiien Wu — Taichuni;. Taiwan

The Haemodynamic Effects of Nitric Oxide (Mathie RT,
CJriffith TM. editors)

reviewed h\ Ronald G Pearl — Stanford. California

Thoracic Anaesthesia: Principles and Practice (Ghosh S. Latimer RD)
reviewed by Lisa M Weavind — Houston, Te.xas

CORRECTIONS

489

491

492

493

494
495

Corrected Location of Author

in the letter ".Aerosols and the Profession of Respiratory Care: Leading the
Way Out of the Foi;" iRespir Care 200l:46(3):275-276)

496

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ALSO
IN THIS ISSUE

CONTINUED

A Monthly Science Journal
Established in 1956

The Official Journal of the

American Association for

Respiratory Care

GUIDELINES. RECOMMENDATIONS, & STATEMENTS

AARC ('liniL-al Practice Guidelines

Blood Gas Analysis and Hemoximetry: 200! Revision & Update

Bods Plolhysmography: 2001 Rc\ision& Update

Exercise Testing for Evaluation of Hvpoxeniia and/or Desaturation:
2001 Revision & Update

Methacholine Challenge Testing: 2001 Revision & Update

Static Lung Volumes: 2001 Re\ision & Update

47th International
Respiratory Congress

San Antonio, TX
December 1-4, 2001

497
498
506

514
523
531

Learn More About
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Outlines techniques and theories, including pressure-limited ventilation, reduced peck
pressure, permissive hypercapnia, weaning and imposed work of breathing, and the
next generation of ventilators. Featuring Neil R, Maclntyre, MD, FAARC, and Richard
D. Branson, BA, RRT, FAARC. 90-min. videotape.
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Managing the Mechanically Ventilated Patient: Chest Tubes, Aerosols,

Endotracheal Tubes

Teaches how endotracheal tubes impose work and create infection risk, the effi-
cacy of various systems, the indications, positioning issues, and drainage issues
for chest tubes. Featuring Neil R. Maclntyre, MD, FAARC, and David J. Pierson,
MD, FAARC. 90-min. videotape.
Item VC71 $49.95 ($99.00 Nonmembers)

Waveform Analysis and Interpretation

Discusses the clinical applications of the primary waveforms, the general kinds of
information they provide, and how to use them to adjust the patient-ventilator
interface. Featuring Jon O. Nilsestuen, PhD, RRT, FAARC, and Richard D. Bran-
son, BA, RRT, FAARC. 90-min. videotape.
Item VC72 $49.95 ($99.00 Nonmembers)

Prevention and Management of Ventilator-Induced Lung Injury

Describes our current concepts of the pathophysiology of ventilator-induced lung
injury. It also covers how to identify patients at risk of barotrauma and the approach
to management of bronchopleural fistula in the ventilated patient. Featuring David J.
Pierson, MD, FAARC, and Richard D. Branson, BA, RRT FAARC. 90-min. videotape.
Item VC52 $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,
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Ventilators and Their Management

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Richard D. Branson, BA, RRT, FAARC, 90-min. videotape.
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Noninvasive Mechanical Ventilation: Its Role in Acute and Chronic
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Describes the modalities currently available in noninvasive ventilation. Results of stud-
ies on acute and chronic respiratory failure ore reviewed, and acceptable indica-
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EDITORIAL OFFICE

EDITOR \H CHIEF

A Monthly Science Journal
Established in 1956

The Ofticial Journal of the

American Association for

Respiratory Care

David J F^icrson MD FAARC

Hiirhoniiw Mrdital Cciilcr
I 'niveisiiy of Witshinglon
St'atilc, Wushiimliiii

ASSOCIATE EDITORS

Richard D Branson RRT FAARC
Univfrsity of Cituinnaii
Cincinnati. Ohio

Charles G Durbin Jr MD I AARC

UnivtTsity of Virf^inia
Charlotte sville. Virginia

EDITORIAL BOARD

Dean R Hess PhD RRT FAARC

Mii\\atlni.\t'tl.^ Gt'twral Hitspihti
tianard Vnivt'nity
Hosiim. Massachusetts

Neil R Maclnlyre MD FAARC
Duke University
Durham North Carolina

James K Sloller MD

Thi- Cleveland Clinic Foundation

Cleveland, Ohio

Alexander B Adams MPH RRT
FAARC

Regions Hospital
St l\uil. Minnesota

Thomas A Barnes HdD RRT
FAARC"

\ortlieustern Lniversit\
Boston, Massachusetts

Joshua O Benditt MD

University of Washini;li>n
Seattle. Washington

Michael J Bishop MD

University of Washini^fon
Seattle. Washington

Lluis L Blanch MD PhD

Hospital de Sahadell
Siihadell, Spain

Bartolome R Celli MD
Tufts University
Boston. .Massachusetts

Robert L Chatburn RRT
FAARC

University Hospitals of Cleveland
Ca.se Western Re.ser\-e Universiiv
Cleveland, Ohio

Patrick J Dunne MEd RRT
FAARC

Health Care Productions
h'ullerton. California

James B Fink MS RRT FAARC

Hines VA Hospital
Loyola University
Chicai^o. Illinois

John E Heffner MD

Medical Universitv of South Carolina
Charleston. South Carolina

SECTION EDITORS

Mark J Heulitt MD FAARC

University of Arkansas
Little Rock Arkansas

Leonard D Hudson MD

University of Washington
Seattle. Washington

Robert M Kacmarek PhD RRT

FAARC

.Massachu.iells General Hospital

Har\ard University

Boston. Massachusetts

Richard H Kallet MS RRT

San Francisco Ciciicral Hospital
University of California San FrancLsco
San Francisco. California

Lucv Kester MBA RRT
FAARC

The Cleveland Clinic Foundation
Cleveland, Ohio

Max Kirmse MD

University of Eriangen-Niimherg
Eriangen. Germany

Toshihiko Koga MD

Koga Hospital
Kurutne. Japan

Mann H KoUef MD
Washington University
St Liniis. Missouri

Shelley C Mishoe PhD RRT

FAARC

Medical College of Georgia

Augusta. Georgia

Marcy F Petrini PhD

University of Mis\i\sippi
Jackson. Mississippi

Joseph L Rau PhD RRT FAARC

Georgia State University
Atlanta. Georgia

Catherine SH Sassoon MD

University of California Irvine
Long Beach. California

John W Shigeoka MD

Veterans Administration Medical Center
Salt Lake Cits. Utah

Martin J Tobin MD
Loyola University
Chicago, Illinois

Jeffrey J Ward MEd RRT

Mayo Medical School
Rochester, Minnesota

Robert L Wilkins PhD RRT
FAARC

Lonia Linda University
Loina Linda. California

Constantine A Manthous

Bridgeport Hospital
Bridgeport, Connecticut

John J Marini MD

University of Minnesota
St Paul, Minnesota

MD STATISTICAL CONSULTANT
Gordon D Rubenfeld MD

University of Washington
Seattle, Washington

Hugh S Malhewson MD
Joseph L Rau PhD RRT FAARC
Drug Capsule

Jon Nilsestucn PhD RRT FAARC
Ken Hargelt RRT
Graphics Comer

Richard D Branson RRT FAARC
Robert S Campbell RRT FAARC
Kittredge 's Corner

Charles G Irvin Phl5

Gregg L Ruppcl Mid RRT RPIT FAARC

PFT Corner

Steven B Nelson MS RRT
RC Web Sites

Patricio Ann Doorley MS RRT
Charles G Durt)in Jr MD FAARC
Test Your Radiologic Skill

Abstracts

Siminiarics of Pertinent Artieles in Other Journals

Editorials, Commentaries, and Reviews To Note

Aspiration Pneumonitis and Aspiration Pneumonia — M;irik PE. N Engl J Med 2001.344(91:
(if).S-67 1 .

Volume of Air in a Lethal Venous Air Embolism — Tnung TJ. Rossberg MI, Hutchins GM.
Anesthesiology 200 1 ;94( 2 ):360-36 1 .

Asthma Control: Where Do We Fail? (editorial)— Kips JC. Pauwels RA. Eur Respir J 2000;
I6(.'i):797-7y8.

Inhaled Nitric Oxide in Adults with the Acute Respiratory Distress Syndrome — Markewit/
BA. Michael JR. Respir Mod 20()();94( I I ); 1023-1028.

Lung-Protective Ventilation in .Acute Respiratory Distress Syndrome: Protection by Re-
duced Lung Stress or by Therapeutic Hypercapnia? (editorial) — Hickliiig KG. Am J Respir
Crit Care Med 2O00;l62(6):2O2l-2022.

Legal .-Vspects of Withholding and Withdrawing Life Support from Critically III Patients in
the United States and Providing Palliative Care to Them — Luce JM. Alpers A. Am J Respir
Crit Care Med 200O-,162(6):2029-2032.

Proceedings of the .\TS Workshop on Refractory .Asthma: Current I'nderstanding. Rec-
ommendations, and Unanswered Questions. .American Thoracic Society. Am J Respir Crit
Care Med 2000;I62(6):234I-235I.

End-Tidal CO,: Physiology in Pursuit of Clinical Applications (editorial) — Levine RL. In-
tensive Care Med 2000;26( 1 1 ): 1595-1597.

Lung-Protective Mechanical Ventilation Strategies in ARDS — Lee WL. Detsky .AS. Stewart
TE. Intensive Care Med 2000;26(S|:1 151-1 155.

Interventional Pulnionology— Seijo LM. Sterman DH. N Engl J Med 2001 ;344( IO):740-749.

Flow Limitation and Dynamic Hyperinflation During Exerci.sc in
COPI) Patients After Single Lung Transplantation — Murciano D. Fer-
relll A. Boczkowski J. Sleiman C. Fournier M, Milic-Emili J. Chest 2000
Nov:ll8(5):l248-l254.

.STUDY OBJECTIVE: Using the negative expiratory pressure (NEP)
method, we have previously shown that patients receiving single lung
transplantation (SLT) forCOPD do not exhibit expiratory tlow limitation
and have little dyspnea at rest. In the present study, we as.sessed whether
SLT patients exhibit How limitation, overall hypennnation. and dyspnea
during exercise. METHODS: Expiratory How limitation assessed by the
NEP method and Inspiratory capacity maneuvers used lo determine end-
expiratory lung volume (EELV) and end-inspiratory lung volume (EILV)
were perfonned al rest and during symptoni-limiled incremental cycle
exercise in eight SLT patients. RESULTS: At the time of the study, the
mean {± SD) FEV,, FVC. functional residual capacity, and total lung
capacity (TLCl amounted to .55 ± 14%. 67 ± 12%. 137 ± 16%. and
1 10 ± 1 1% of predicted, respectively. At rest, all patients did not expe-
rience expiratory How limitation and were without dyspnea. At peak
exercise, the maximal mechanical power output and maximal oxygen

consumption amounted to 72 ± 20% and 65 ± 8% of predicted, respec-
tively, with a maximal dyspnea Borg score of 6 ± 3. All but one patient
exhibited flow limitation and dynamic hyperinnation; the EELV and
EILV amounted to 74 ± 5%- and 95 ± 9% TLC. respectively. The patient
who did not exhibit tlow limitation during exercise had the lowest dys-
pnea score. CONCLUSION: Most SLT patients for COPD exhibit expi-
ratory tlow limitation and dynamic hyperinllation during exercise, whereas
maximal d\spnca is variable.

Pulmonary Complications Following Lung Resection: A Compre-
hensive Analysis of Incidence and Possible Risk Factors — Steph.in F.
Boucheseiche S. Hollande J. Flahaull A. ChelTi A. Ba/elly B. Bonnet F.
Chest 2000 Nov;l I8(5):I263-I270.

STUDY OBJECTIVES: To assess the incidence and clinical implications
of postoperative pulmonary complications (PPCs) after lung resection,
and to identify possible associated risk factors. DESIGN: Retrospective
study. SEITING: An 885-bed teaching hospital. PATIENTS AND
METHODS: We reviewed all patients undergoing lung resection during
a 3-year period. The following information was recorded: preoperative

432

Respiratory Care; • Ma-i 2001 Vol 46 No 5

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The Provocholine^challenge provides for a
sensitive and generally accurate diagnosis of
bronchial hyperactivity. ,

WARNING: Because of the potential for severe
bronchoconstriction, the Provocholine challenge
should not be performed on any patient with
clinically apparent asthma, wheezing, very low base
line pulmonary test or receiving a beta-adrenergic ^
blocking agent. Administration of Provocholine to
patients with any condition that could be adversely
affected by a cholinergic agent should be undertaken
only if benefit outweighs the potential risks.

qryj^n adjacentpage)

Provochflline ijFavailable

y
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At'i'C ACIC (Cyprus) Limited
PO Box 530"'0, 3300 Limassol Cyprus
Tel: ++357-S-S78696 or ++3>--s-57882i
Fax: ++357-5-563980
e-mail: acic@spidcrnet.com.cy

> Registered trademark o( mcthapharm inc.

PROVOCHOLINE*

(rnethachollnB chloride)

FOR INHALATION

NOT FOB INJECTION

BEFORE PRESCRIBING. PLEASE CONSULT COMPLETE
PRESCRIBING INFORMATION

PROVOCHOLINE (methachollne ctilorlde powder tor
Inhalation) Is a bronchoconstrlctor agent lor diagnostic
purposes only and should not be used as a therapeutic
agent PROVOCHOLINE inhalation challenge should be
pedormed only under the supervision of a physician
trained in and thoroughly familiar with all aspects of the
technique of metfiachollne challenge, al contraindications,
warnings and precautions, and the management of
respiratory distress Emergency equipment and medication
should be immediately available to treat acute respiratory
distress PROVOCHOLINE should be administered only by
Inhalation Severe btorchoconstnctlon and reduction In
respiratory (unction can result Irom the administration of
PROVOCHOLINE Patients with severe hyperreactivity ol
the airways can experience bronchoconslriction at a
dosage as low as 025 mg/mL (0 125 cumulative units)
If severe broncho-constriction occurs. It should be
reversed Immediately by the administration of a rapid-
acting Inhaled bronchodllator agent (beta agonist)
Because o( the potential for severe bronchoconstrlctlon.
PROVOCHOLINE challenge should not be pertormed In
any patient with clinically apparent asthma, wheezing or
very low baseline pulmonary function tests (e g , FEVl
less than 1 to 1 5 liter or less than 70% ol the predicted
values) Please consult standard nomograms for
predicted values.

wrtti baseline value after Inhalaflon of control NaCI solution.
Calculate and record target value before PROVXHOLINE
challenge ts started

Dilutiortt: {Note Do not Inhale powder Do not handle this
matenal If you have asthma or hay fever) Make all dilutions
with 9% NaO injection containing 4% phenol (pH 7 0) using
sterile empty USP Type 1 boroslHcate glass vials After adding
NaCl solution, shake eac^ vial to obtain a dear solution

INDICATIONS AND USAGL Diagnosis of bronchial airway
hyperreactivity In subjects who do not have clinically
apparent asthma

CONTRAINDICATIONS: PROVOCHOLINE Is contraindicatfid in
patients with known hypersensitivity to this drug or other
par^sympattwmimebc agents. Repeated administration by
Inhalation other than on the day that a patient undergoes
challenge with Increasing doses Is central ndica ted Inhalation
challenge should not be performed In patients receiving any
beta adrenergic blocking agent (see WARNING)
WARNING: General: Administration to patients with epilepsy,
cardiovascular disease accompanied by bradycardia,
vagotonia, peptic ulcer disease, thyroid disease, urinary tract
obstruction or other condition that could be adversely affected
by a cholinergic agent only if benefit outweighs potential risks
tnformation tor Patiente: Instruct patients regarding symptoms
that may oaur as a result of the test and to manage. Women
should Inform physician if pregnant {or date of last menses or
date/result ol last pregnancy test)
C a nanogenesia, Mtbgenesb, knpainnent of Ferttty: There have
been no studies v^th methachollne chloride that pemitl an
evaluation ol its carcinogenic or mutagenic potential or Its effect on
fertility

Pregnancy: Methachollne chloride should be given to a
pregnant woman only if dearly needed IN FEMALES OF
CHILDBEARING POTENTIAL. PROVOCHOLINE INHAUTION
CHALLENGE SHOULD BE PERFORMED EITHER WTTMIN TIN DAYS
FOLLOWING THE ONSET OF MENSES OR WITHIN 2 WEEKS OF A
NEGATIVE PREGNANa THST

Nursing Mothers: Do not administer during nursing since It Is
unknown whether Inhaled methachollne chloride is excreted in
breast milk.

Pediatric Use: Safety and efficacy have not been established
in children <5 years

ADVERSE REACTIONS: Adverse reactions associated with 153
inhaled methachollne chloride challenges Include one
occurrence each of headache, throat irritaton. lightheadedness
and itching Administer only by Inhalation Oral or Injected
methachollne chionde is reported to be associated with nausea
and vomiting, substernal pain or pressure, hypotensjon. tainting
and trar«ient complete heart block (See OVERDOSAGE)
OVERDOSAGE: Administer only by inhalation Overdosage with
oral or injected methachollne chloride can result in a syncopal
react)on. wnth cardiac arrest and loss of consaousness Senous
toxic reactions should be treated wrtti 0.5 mg to 1 mg of atropine
sulfate, administered IM or IV

DOSAGE AND ADMINISTRATION: Belore challenge, perform
baseline pulmonary function tests Subject must have an FEVl
ol al least 70% ol the predicted value Target level fa positive
challenge Is 20% reduction In the FEVl compared

Dilution Sequence

vuto
(CooMn)

Utfllpl* PiDmtI I«t«ng
3 Mab PnOVOCHOUNQ

Bngla Pa«Mrt toaUng

RSmoATU

Md 4 mL NaO Inlodton'
to wti ol two ?0 rrl vUb
o( PROVDCMOUt*

Add 4 ITU. 4aa Injection-
to i 20 ml vUt ol
PflOVOCHOUNE (Vial *J

(lOmij'iTtJ

flBmoveSmLlrorivlilAI,
bmsts/ to tnotlw irtiJ tnd
add 4 S ml NiQ lri4*cton'

Hamwi I (it bom vUl A.
kandai to inollw vlai and
Udl S ml Naa miectton-

RMKove 1 rm. rrom vtti U,
imstti to inoitief Mai and
add 9 irt. fiiO in(9c1ion*

Ramova I m tram vtai A.
lran$l«r b anGtiwi vUl and

idd 9 ml N*a ln(ecUon-

(0 !5 moW_l

Ramova t irL tan vtal C,
hantiM to anothai MU and
mU 9 ml NaQ Inladlon*

Ramovi 1 nt bom vbi C.
kinsfar to anomer utai and
add g m Naa infecDon*

Remow 1 wL Irom vtal 0.
ttanHai to tnollw «lal and
add 9 niL KaO ln( action'

Ramova l wL Irom vUl 0,
trmstsi to tnoirw viaJ and
add S mL NaQ Injection-

Prepan nn iSy o( chjlefuje

nw ifecixF - 9% soduTi cNortde infectori antai>*^

Store dilutions A through D for not more than 2 weeks at 2* to
8* C (refrigerated) (Freezing does not affect stability) Prepare
Vial E on day of challenge Use a sterile bacterial- retentive
filter (porosity 0.22 mm) to transfer solution from each vial
(al least 2 ml) to nebulUer. Procedure: Pedonn challenge by
giving subject ascending serial corKcntrations ol PROVOOIOUNE.
At each concentration, administer five breaths by a nebulizer
that permits Intermittent delivery time ol 0.6 seconds by a
dosimeter At each of live Inhalations of a serial
concentration, the subject begins at lunctlonal residual
capacity and slowly and completely Inhales the dose
delivered Within 5 minutes. FEVl values are determined.
The procedure ends either when there Is ^ 20% reduction
In FEVl compared with baseline NaCI solution value (i e . a
positive response) or If 186 86 total cumulative units has
been administered (see table below) and the FEVl has
been reduced by 14% or less (I e . a negative response) If
there Is a reduction ol 15% to 19% In the FEVl compared
with baseline, either the challenge may be repeated at that
concentration or a higher concentration may be given as
long as dosage administered does not exceed cumulative
units > 188.68 The lollowlng Is a suggested schedule lor
administration.

025 mo/mL

0125

HKSEmH
l|i|Mgj|fl

0125

25 mfl/mt

125

1 375

2 5 mg/mL

125

13 38

10 mg/mL

' 63 88

25 mj/mL

125

188 88

An inhaled beta-dgonist may be administered after challenge
to expedite return of FEVl to baseline and to relieve discomfort
of subject Most patients revert to normal pulmonary function
within 5 minutes following bronchodllators or within 30 to 45
minutes without any bronchodilator

fJl'ethaph^rm inc.

131 Clarence Street

Brantford, Ontario N3T 2V6 Canada

Tel: (519) 751-3602, 1-800-287-7686

Fax: (519) 751-9149

e-mail: sales@metliapharm.C()m

Web Site: www.methapharm.com

2001

I Respiratory
I Care
Open Forum

The AARC and its
science journal,
Respiratory Care, invite
submission of brief
abstracts related to any
aspect of cardio-
respiratory care. The
abstracts will be
reviewed, and selected
authors will be invited to
present posters at the
Open Forum during the
AARC International
Respiratory Congress in
San Antonio, TX,
Dec. 1 -4. Accepted
abstracts will be
published in the October
2001 issue of
Respiratory Care and are
automatically considered
for ARCF research
grants. Membership in
the AARC is not required
for participation.

Specifications available at
www.rcjournal.com, or
call Linda Barcus at
(972)243-2272. M

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assessment (including pulmonary function tests), clinical parameters, and
intraoperative and postoperative events. Pulmonary complications were
noted according to a precise definition. The risk of PPCs associated w ith
selected factors was evaluated using multiple logistic regression analysis
to estimate odds ratios (ORs) and '■)5''r confidence intervals (CIs). RE-
SULTS: Two hundred sixty-six patients were studied (87 after pneumo-
nectomy. 142 after lobectomy, and 37 after wedge resection). Sixty-eight
patients (25%) experienced PPCs, and 20 patients (7.5%) died during the
30 days following the surgical procedure. An American Society of An-
esthesiology (ASA) score > 3 (OR, 2.11: 95% CI, 1.07 to 4.16; p <
0.02), an operating lime > SO min (OR. 2.()X; 95"/;- CI. 1.09 to 3.97; p <
0.02). and the need lor postiiperalive mechanical ventilation > 48 min
(OR. 1.96; 9.S';f CI. 1.02 to 3.75; p < 0.04) were independent factors
associated with the development of PPCs, which was, in turn, associated
with an increased morlality rate and the length of ICU or surgical ward
stay. CONCLUSIONS: Our results confirm the relevance of the ASA
score in a selected population and stress the importance of the length of
the surgiciil procedure and the need for postoperative mechanical venti-
lation in the development of PPCs. In addition, preoperative pulmonary
function tests do not appear to contribute to the idciUificatioii ol high-risk
patients.

I he Appropriate .Setting of Noninvasive Pressure Supporl N'enlila-
tion in .Stable COI'I) Patients — Vitacca M, Nava S. Conlalomeri M,
Bianchi L. Porta R. Clini t. Ambrosino N. Chest 2(XH) Nov; 1 1 8(5): 1286-
1 293.

.STUDY OBJECTIVE: To evaluate the short-term physiologic effects of
two settings of nasal pressure-support ventilation (NPSV) in stable COPD
patients with chronic hypercapnia. DESIGN: Randomized controlled phys-
iologic study. Sirn'ING: Lung function units and outp;iticnl clinic of two

affiliated pulmonary rehabilitation centers. PATIENTS: Twenty-three pa-
tients receiving domiciliary nocturnal NPSV for a mean ( ± SD) duration
of 31 i 20 months. METHODS: Evaluation of arterial blood gases.
breathing pattern, respiratory muscles, and dynamic intrinsic positive
end-expiratory pressure (PEEP, jy„) during both unassisted and assisted
ventilation. Two settings of NPSV were randomly applied for 30 min
each: (I) usual setting (U), the setting of NPSV actually used by the
individual patient at home; and (2) physiologic setting (PHY), the level
of inspiratory pressure support (IPS) and external positive end-expiratory
pressure (PEEPe) tailored U) patient according to invasive evaluation of
respiratory muscular function and mechanics. RESULTS: All patients
tolerated NPSV well throughout the procedure. Mean U was IPS, 16 ±
3 cm H,0 and PEEPe, 3.6 ± 1.4 cm H,0; mean PHY was IPS. 15 ± 3
cm H,0 and PEEPe, 3.1 ± 1.6 cm H,0. NPSV was able to significantly
(p < 0.01 ) improve arterial blood gases independent of the setting ap-
plied. When compared with spontaneous breathing, both settings induced
a significant increase in minute ventilation (p < 0.01 ). Both settings were
able to reduce the diaphragmatic pressure-time product, but the reduction
was significantly greater with PHY (by 64%; p < 0.01) than with U
(56%^; p < 0.05). Eleven of 23 patients (48%) with U and 7 of 23 patients
(30%) with PHY showed ineffective efforts (IE); the prevalence of IE
(20 ± 39% vs 6 ± 11% of their respiratory rate with U and PHY.
respectively) was statistically dilferent (p < 0.05). CONCLUSION: In
COPD patients with chronic hypercapnia. NPSV is effective in improv-
ing arterial blood gases and in unloading inspiratory muscles independent
of whether it is set on the basis of patient comfort and improvement in
arterial blood gases or tailored to a patient's respiratory muscle effort and
mechanics. However, setting of inspiratory assistance and PEEPe by the
invasive evaluation of lung mechanics and respiratory muscle function
may result in reduction in ineffective inspiratory efforts. These short-
term results must be confirmed in the long-term clinical setting.

Respiratory Care • May 2001 Voi 46 No ."^

435

Abstracts

The Spirometric EfTicacy of Once-Daily Dosinu with Tiotropium in
Stahle COPD: A 13-wtek Multicenter Trial— C'asahuii R. Briggs DD
Ji. Doiioluic- JI-, Serbs C\\. Mcnjogc SS, Witck TJ Jr. Chest 2000 Nov;
1 18(5); 1244-302.

STL'D'l' OBJECriVR: Tci cuniparc the bronehiiclilator clficaey and safety
of tiotropium anJ placebo. DESIGN: A .^-nionlh. randoinl/ed. double-
blind, placebo-controlled, multicenter trial. SE'ITING: Outpatient. PA-
TIENTS; Four hundred seventy patients with stable COPD (mean FEV , =
38.6% predicted). INTERVENTIONS; Tiotropium 18 ng (N = 279) or
placebo (N = 191) given once daily via a lactose-based diy-powder
inhaler device. MEASUREMENTS AND RESULTS; Spirometry was
evaluated on days 1. 8. 50. and 92, Data were expressed as the mean
trough lie. before morning dose; 2.^ to 24 h after previous dose) and
average response observed in the .3 h after the ilose was received. Tiotro-
pium produced significant improvement in trough FEV, and FVC. av-
eraging I29( greater than baseline on day 8; these improvements were
maintained on days 50 and 92. The average postdose FEV, was \69c
greater than baseline on day 1 and 20% greater than ba.seline on day 92;
FVC was 17% greater than baseline on day 1 and 19% greater than
baseline on day 92. Tiotropium was significantly more effective than
placebo in both trough and average FEV, and FVC response (p < 0.001 ).
These spirometric effects were corroborated by significant improvements
in daih morning and evening peak expiratory How rate, as well as a
reduction in -as-needed" albuterol use. Symptoms of wheezing and short-
ness of breath were significantly less in patients receiving tiotropium. and
the physician global assessment nt)ted overall improvements with those
treated with tiotropium relative to placebo. The most common reported
adverse event after tiotropium was dry mouth (9.3% vs 1 .6% relative to
placebo; p < 0.05). CONCLUSIONS; These data demonstrate that tiotro-
pium is a safe and effective once-daily anticholinergic bronchodilator and
should prove useful as Urst-line maintenance therapy in COPD.

Appropriateness ofDomiciliary Oxygen Delivery— GuyattGH.McKim

DA, Au.stin P. Bryan R. Norgren J, Weaver B, Goldstein RS. Chest 20(X)
Nov;118(5);1303-1308.

OBJECTIVE; Almost every country in the developed world has a do-
miciliary oxygen program. Whether recipients meet program criteria has
not been rigorously studied. DESIGN; Cross-sectional survey. PARTIC-
IPANTS; Two hundred thirty-seven patients receiving domiciliary oxy-
gen in the Ontario Ministry of Health Home Oxygen Program (HOP).
METHODS; A respiratory therapist visited the patients' homes and ad-
ministered questionnaires, obtained resting arterial blood gas measure-
ments, and conducted a standardized home exercise test while monitoring
oxygen saturation using an oximeter. Measures of outcoine; We evalu-
ated the extent to which patients met HOP criteria that are based on the
inclusion criteria of randomized trials showing the life-prolonging effects
of domiciliary oxygen. We also assessed the extent to which the patients'
oxygen prescription was consistent with the results of rest and exercise
testing. RESULTS; Ninety-six of 237 participants (40.5%; 95% confi-
dence interval. 34.3 to 46.8) did not meet criteria for home oxygen.
Patients aged £ 70 years were more likely to meet criteria (71 of 105
patients; 67.9%) than those > 70 years old (70 of 132 patients; 53.0%).
The proportion of patients meeting criteria was similar whether the re-
ferring physician was a specialist (71 of 1 12 patients: 62.5%) or a pri-
mary-care physician (69 of 123 patients; 56.1%). A very important health
benefit from oxygen was identified among 82% of those who met criteria
and ii>iV< of those who did not. Patients received higher fiow rates than
our criteria suggested were appropriate. Agreement between the inde-
pendently assessed oxygen prescription at rest and the patients' report ol
oxygen use was extremely poor (chance-corrected agreement k. 0.17), as
was agreement concerning optimal exercise fiow rates (k. 0.26). CON-
CLUSIONS; Current procedures for administration and reimbursement
of home oxygen result in a large proportion of recipients not meeting

criteria, as well as the prescription of excessive oxygen flow rates. These
results are likely to apply to many juri,sdictions and suggest a large
potential loi nioie efficient resource allocation.

Asthmatic .Suhjecis .Symptomaticallj Wiirsi- at Work: Prevalence
and Characterization Among a General .Asthma Clinic Population —

Tarlo SM. Leung K. Broder I. Silverman F, Holness DL. Chest 2000
Nov:118(5);1309-1314.

STUDY OBJECTIVES; To assess the prevalence of a historical occu-
pational component to asthma in an adult asthma clinic and to compare
characteristics of asthmatic subjects with and without work-attributed
symptoms. DESIGN; A retrospective review of data obtained from a
physician-administered questionnaire, answers to which were obtained at
the initial patient visit of asthmatic subjects, and which included specific
questions regarding the relationship of work to symptotns. Chart review
data were used to supplement information on workplace exposures and
investigations. SETTING; A university-based secondary- and tertiary-
refeiTal asthma clinic. Patients; Seven hundred thirty-one adult asthmatic
subjects who were referred for assessment and management of asthma.
INTERVENTIONS; Statistical analyses of asthmatic subjects with and
without work-attributed symptoms and a determination, from chart re-
view, of the likelih<iod of causes for symptomatic worsening of asthma at
work. MEASUREMENTS AND RESULTS; Sixty percent of the patients
(435) had adult onset of asthma, among whom 310 patients (71%) were
employed at the time of their visit. Fifty-one patients reported their
asthma to be worse at work (ie, 16% of adult-onset working asthmatic
subjects). Sixteen of these patients (31%) had likely or possible sensi-
tizer-induced occupational asthma (OA). and 499; likely had aggravation
of underlying asthma. The other 20% of patients had possible OA or
aggravation of underlying asthma at work. CONCLUSIONS; Adult-on-
set asthmatic subjects commonly report a worsening of asthma at work,
more commonly on the basis of likely aggravation of underiying asthma
than on the basis of likely or possible OA.

Effects of Weight Loss on Peak Flow \ ariability. Airways Obstruc-
tion, and Lung \ olunies in Obese Patients with .Asthma — Hakala K.
Stenius-Aamiala B. Sovijarvi A. Chest 2000 Nov;l 18(5):I315-1321.

STUDY OBJECTIVES; To clarify the pathophysiologic features of the
relation between asthma and obesity, we measured the effects of weight
reduction on peak expiratory How (PEF) variability and airways obstruc-
tion, compared to simultaneous changes in lung volumes and ventilatory
mechanics in obese patients with stable asthma. METHODS; Fourteen
obese asthma patients ( 1 1 women and 3 men; aged 25 to 62 years) were
studied before and after a very -low -calorie-diet period of 8 weeks. PEF
variability was determined as diumal and day-to-day variations. FEV,
and maximal expiratory flow values were measured with a flow-volume
spirometer. Lung volumes, airways resistance (R^^). and specific airways
conductance were measured using a constant-volume body plethysmo-
uraph. Minute ventilation was monitored in patients in supine and stand-
ing positions. RESULTS; As patients decreased their bodv mass index
(SD) from 37.2 (3.7) to 32.1(4.2) kg/m" (p < 0.001 ). diurnal PEF vari-
ation declined from 5.5% (2.4) to 4.5% (1.5) (p = 0.01 ). and day-to-day
variation declined from 5.3% (2.6) to 3.1% (1.3) (p < 0.005). The mean
morning PEF. FEV,. and FVC increased after weight loss (p = 0.001.
p < 0.005. and p < 0.05. respectively). Flow rate at the middle part of
FVC (reF,,.,,) increased even when related to lung volumes (FEF,,.,,/
FVC: p < 0.05). Functional residual capacity and expiratory reserve
volume were significantlv higher after weight loss (p < 0.05 and p <
().()()5. respectively). A significant reduction in R,„ was found (p <
0.01 ). Resting minute ventilation decreased after weight loss (p = 0.01 ).
CONCLUSION; Weight loss reduces airwav s obstniction as well as PEF
variability in obese patients with asthma. The results suggest that obese

4.Vl

Rrsi'iRATORY Care • MAt 2001 Vol 46 No 5

AnSIKAt'lS

paliciils boncni lioiii \vcii;ht loss hy improvfi.1 piilmoiuny nK-i.lianii.s ami
a boiler conlrol ol airways nh'-lruclion

Inspinitorv KHorl Si'iisiiliiiii In Aildcil KisisliM' l.iiailiiin in Taliiiils
«itli ObslriiiiiM' Slt-ip \pni-a Tun Y. Hiila \V. Okabc S. Kiknchi Y.
Kurosawa H. lahaia M. Shirato K CIk-sI 2IM«) NomI ISlSlil.VU-l.V^S.

STUDY OBJIXI l\i;S: Repealed episodes ol upper-airway occlusion
are itie [iiain eharaclensties olpatlenls w itii olislrueli\e sleep apnea (OS A)
during sleep. It has been reported ihat an iinpainnenl in the sensation ol
deleclion and a depression of ventilatory compensation to added load
could be observed in such patients. In this study, we examined patients
with OSA to evaluate the inspiratory ctTorl sensation (lES). ventilation.
and mouth occlusion pressures during added resistive loading while awake
and to determine whether they can be reversed by nasal continuous
positive airway pressure (CPAP) treatment. DHSIGN: A hospital-based
case-control study. Sb'ITlNG: A sleep laboratory of a medical unit in
Japan. SUBJliC IS: Seventeen patients with moderate to severe OSA and
10 control subjects were included in this study. Mr..-\SLIRF;MF.NTS: .Ml
patients with OSA had undergone standard nocturnal polysomnography.
Patients with OSA and control subjects were evaluated lor lES measured
by a modified Borg score, ventilation, and mouth occlusion pressure
during control and inspiratory resistive loaded breathing. These tests
were repeated in all patients with OSA after 2 weeks of nasal CPAP
treatment. RESULTS; lES to inspiratory resistive loading was lower in
patients with OS.A than in control subjects. There were no differences in
ventilation and mouth occlusion pressure between patients and control
subjects during loaded breathing. After 2 weeks of nasal CPAP, the
decreased lES was increased in patients with OSA. CONCLUSION: In
patients with OSA. the decreased lES to inspiratory resistive loaded
breathing is reversible with nasal CPAP. This could be one additional
benefit of nasal CPAP in the treatment of OSA.

Prevention of Pulmonary Morbidity for Patients witli Neuromuscu-
lar Disease— Tzeng AC, Bach JR. Chest 2()()() Nov;l 18(.'5):LW()-l.^'«i.

STUDY OBJECTIVE: To evaluate the effects of a respiratory muscle aid
protocol on hospitalization rates for respiratory complications of neuro-
muscular disease, DESIGN: A retrospective cohort study. METHODS: A
home protocol was developed in which oxyhemoglobin desaturation was
prevented or reversed by the use of noninvasive intermittent positive-
pressure ventilation and manually and mechanically assisted coughing as
needed. The patients who had more than one episode of respiratory
failure before having access to the protocol were considered to have had
preprotocol periods (group 1). Other patients were given access to the
protocol when their assisted peak cough flows decreased to < 270 L/min
before any episodes of respiratory distress (group 2). The number of
hospitalizations and days hospitalized were compared longitudinally for
preprotocol and protocol access periods (group 1). In addition, avoided
hospitalizations were identified as "episodes" of need for continuous
ventilatory support and desaturations reversed by assisted coughing that
were managed at home. Data were segregated by access to protocol and
by extent of baseline ventilator use. RESULTS: Of the 47 group 1 pa-
tients with preprotocol periods who have subsequently had episodes, 10
had episodes before requiring ongoing ventilator use. They had 1.06 <
0.84 preprotocol hospitalizations per year per patient and 20.76 ± .■?6.0I
hospitalization days per year per patient over 3,42 ± 3,36 years per
patient vs 0.03 ± 0, 1 1 hospitalizations per year per patient and 0,06 ±
0,20 hospitalization days per year per patient with protocol use over
1.94 i 0.74 years per patient. Of these 47 group 1 patients, 33 eventually
required part-time ventilatory aid and, using the protocol as needed, had
0.08 ± 0.17 hospitalizations per year per patient and 1.43 ± 3.71 hos-
pitalization days per year per patient over 3.91 ; 3.50 years per patient,
as opposed to 1.40 i l.% h<ispitalizations per year per patient and
20,14 ± 41.15 hospitalization days per year per patient preprotocol and

preventilator use over 5. 89 ± 6.89 years per patient. Twelve patients in
group I eventually required continuous noninvasive ventilation and, us-
ing the protocol as needed, had 0.07 ;t 0.14 hospitalizations per year per
patient and 0.39 1 0.73 hospitalization days per year per patient over
5.35 ± 5.10 years per patient by comparison with 0.97 r 0.74 hospital-
izations per year per patient and 10.39 ± 8.66 hospilalizalion days per
year per patient over 2.18 ± 1.9! years per patient preproUKol and
preventilator use. For the 94 patients overall when having access to the
protocol. 1.02 i 0.99 hospitalizations per year per patient were avoided
by 14 patients before requiring ongoing ventilator use over 4.82 i 1.61
years. 0.99 i 1.12 hospitalizations per year per patient were avoided by
73 part-time ventilator users over 3.21 _ 3.15 years, and 0.80 i 0.85
hospitalizations per year per patient were avoided by 31 full-time ven-
tilator users over 4.78 ± 4.88 years. All preprotocol and protocol rate
comparisons were statistically significant at p < 0.004. CONCLUSION:
Patients have significantly fewer hospitalizations per year and days per
year when using the protocol as needed than without the protocol. The
use of inspiratory and expiratory aids can significantly decrease hospi-
talization rates for respiratory complications of neuromuscular disease.

Dittirent Response to Doublinuand lourfold Dose Increases in Metha-
chuline I'roMication Itsts in Healthy Subjects — Sundhlad BM. Malm-
berg P, Larsson K, Chest 2000 Nov;l 18(5):1371-L377.

RATIONALE: In a moditicil mclhacholinc provocation test that was
used to study changes in airway responsiveness to occupational irritants
or sensitizers in healthy subjects, two protocols were used: a long pro-
tocol (doubling methacholinc concentrations between dose steps) or a
short protocol (fourfold increases in concentration). This modified metha-
choline provocation allows measurements of the provocative dose caus-
ing 209^ decrease in FEV, (PD,,,) in a high proponion of a normal
population. METHODS: The distribution of PD^o was investigated in
healthy nonatopic men without history of allergy or asthma .symptoms
using the long protocol (n = 101) or the short protocol (n = 309). In
addition, 30 healthy subjects underwent methacholinc provocation tests
using both protocols. RESULTS: PD,„ was defined in 79'7f of subjects
w ith the long protocol and in 48'} of subjects with the short protocol. The
provocative concentration of methacholinc causing a 2()'< decline in
FEV, (PC,„1 and PD,„ were significantly lower using the long protocol:
long-protocol PC,,, (median 125th to 75th percentilel), 19.9 mg/mL (3.9
to > 32 mg/mL) compared with short-protocol PCjn. > 32 mg/niL (8,7
to >32 mg/mL; p < 0.0001); long-protocol PD,o. 4.2 mg (1.6 to 20 mg)
compared with short-protocol PD,„. > 13.7 (2.6 to > 13.7 mg; p =
0.006). The differences in PD,,, using short and long protocols were
confirmed in a randomized trial of 30 healthy subjects tested with both
protocols. CONCLUSION: Using doubling concentrations. PC,,, and PD,,,
could be defined in a higher proportion of healthy subjects than a pro-
tocol using fourfold dose increases. Furthermore, the doubling protocol
results in a PD,,, estimate that is less than half the value obtained when
using a protocol with fourfold concentrations between dose steps. The
difference remains, whether the methacholinc effect is regarded as cu-
mulative or noncumulative. The explanation for the difference between
the protocols is unclear.

Routine Pulse Oximetry Durini; Melhacholine Challenges Is Unnec-
essary for Safety -Cockci oil DW. lliiisl IS. Marciniuk DD. C.'llon 1)J.
Laframhoisc K1-. Nagpal AK. Skomro RP. Chest 2000 No\;l IS(5):1378-
1381.

BACKGROUND: Methacholine-induccd bronchoconstriction is associ-
ated with significant hypoxemia, which can be assessed noninvasively by
transcutaneous oxygen tension and pulse oximetry. OBJECTIVES: To
assess the value of the monitoring of finger pulse oximetry during routine
methacholinc challenges in a clinical pulmonaiy function laboratory with
regard to both safety and the possibility that a significant fall in oxygen

Respiratory Carf • May 2001 Vol 46 No 5

437

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17th Annual Phil Kittredge Memorial Lecture

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Abstracts

saluralion as iiicaMirL-tl hy pulse oximclry (S|„,,) mijihl he a useful sur-
rogate lor delerTiiining the response to melhacholiiie. Mli IHODS: Two
hundred eonseeutive patients undergoing diagnostie niethaeholine chal-
lenges in the pulmonary function laboratory of a tertiary-care, university-
based referral hospital were studied. Methacholinc challenges were per-
formed by the standardized 2-niin tidal breathing technique, and the
Af-'liV, was calculated from the lowest postsaline solution inhalation to
the lowest poslmelhacholinc inhalation value. S,,,,. was measured imme-
diately prior to each spirogram, and the AS,,,,, was measured from the
lowest postsaline solution inhalation value to the lowest postmethacho-
linc inhalation value. We examined the data lor safety (ie. any S^o,
value < 90). Based on previous reports, we used a ASpo, of a 3 as
significant and looked at the sensitivity, specificity, and positive and
negative predictive values for ASpo, s 3 vis-a-vis a fall in FEV , of a
\5<7c. RESULTS: There were 1 19 nonresponders (AFEV ,. < 15%) and
81 responders. The baseline FEV , percent predicted was slightly but
significantly lower in the re.sponders (responders | ± SD|, 91.6 ± IS')^;
nonresponders. 96.4 ± \4<7c: p < ().05l. AS^,,, was 3.1 ± 1.6 in the
responders and 1.6 ± 1.8 in the nonresponders (p < 0.001 ). There was
a single recording in one patient of S^o, < 90 (88). A AS|,„, a 3 had a
sensitivity of 68%. a specificity of 73%, a positive predictive value of
63%, and negative predictive value of 77% for a fall in FEV , a 15%.
CONCLUSIONS: Pulse oximetry is not routinely useful for safety mon-
itoring during methacholine challenge. ASp,,, is not helpful in predicting
a positive spirometric response to methacholine. However, the negative
predictive value is adequate to allow the ASp,,, to be used as an adjunct
in assessing a negative result of a methacholine test in patients w ho have
difficult) perfonning spirometi^.

.\ Mcta-Analysis of Prospective Trials Comparinj; Percutaneous and
Surgical Tracheostomy in Critically III Patients — Freeman BD. Isa-
bella K. Lin N, Buchman TG. Chest 2000 Nov;l I8(5):14I2-I418.

STUDY OBJECTIVES: Tracheostomy is one of the most commonly
performed procedures in the patient receiving long-temi mechanical ven-
tilation. While percutaneous dilational tracheostomy (PDT) is becoming
increasingly utilized as an alternative to conventional surgical tracheos-
tomy, most literature evaluating these two techniques is neither prospec-
tive nor controlled. We perforined a meta-analysis of available prospec-
tive controlled studies comparing PDT and surgical tracheostomy in
critically ill patients to more fully undersl-and the relative benefits and
risks of these two procedures in this population. DESIGN: Meta-analysis
using Manlel-Haenszel fixed effect model. INTERVENTIONS: We per-
fomied searches of MEDLINE. Current Contents. Best Evidence. Co-
chrane, and HealthSTAR databases from 1985 to present to identify
prospective controlled studies comparing PDT and surgical tracheostomy
in critically ill patients. After establishing clinical and statistical homo-
geneity (Q: statistic), studies were analyzed by a Mantcl-Haenszel fi.\ed
effect model. For each clinical end point examined. PDT and surgical
tracheostomy were compared by calculating either absolute differences
or odds ratios (ORs) with 95%j confidence intervals (CIs) for continuous
or discrete variables, respectively. Measurements and results: We pooled
data from five studies (236 patients) satisfying our search criteria to
analyze eight clinical end points. Operative time was shorter for PDT
than surgical tracheostomy: absolute difference with 95% CI. 9. 84 min
(7.83 to 10.85 min). There was no difference comparing PDT and sur-
gical tracheostomy with respect to overall operative complication rates:
OR with 95% CI. 0.732 (0.05 to 9.37). However, relative to surgical
tracheostomy, PDT was associated with less perioperative bleeding (OR
with 95% CI, 0.14 [0.02 to 0.39]), a lower overall postoperative com-
plication rate (OR with 95% CI. 0.14 |0.()7 to 0.29]). as well as a lower
postoperative incidence of bleeding (OR with 95% CI. 0.39 [0.17 to
0.881), and stomal infection (OR with 95% CI, 0,02 [0.01 to 0.07]). No
difference was identified in days intubated prior to tracheostomy (abso-
lute difference with 95% CI. 0.16 days ]- 0.9 to 1.22 days]), overall

procedure-related complications (OR with 95% CI. 0.73 |().()6 to 9.37]).
or death (OR with 95% CI. 0.63 10.18 to 2.20]) comparing these two
techniques. CONCLUSIONS: Despite its popularity, there are currently
only a limited number of small studies prospectively evaluating PDT and
surgical tracheostomy. Our meta-analysis of these studies suggests po-
tential advantages of PDT relative to surgical tracheostomy, including
ease of performance, and lower incidence of peristoinal bleeding and
postoperative infection. If confimied by additional, adequately powered
prospective trials, these findings support PDT as the procedure of choice
for the establishment of elective tracheostomy in the appropriately se-
lected critically II! patient.

End-of-l.il'e tare in the U'l : Ireatnients Provided when Life Sup-
port Was or Was Not Withdrawn—Hall Rl. Rocker GM. Chest 2000
Nov;ll8(5):l424-I430.

STUDY OBJECTIVE: To compare and contrast use of technology, phar-
macology, and physician variability in end-of-life care of ICU patients
dying with or without active life support. DESIGN: Retrospective cohort
study. SETTING: Two medical-surgical tertiary-care ICUs in a Canadian
regional referral leaching hospital. P.ARTICIPANTS: One hundred sev-
enty-four patients who died between July I. 1996. and June 30. 1997.
INTERVENTION: Data abstraction from medical records. RESULTS:
Patients in whom life support was withheld or withdrawn (138 of 174,
79%) were older (65 ± 16 years vs 55 ± 18 years; p < 0.05 [mean ±
SD]). Once the decision to withdraw life support was made, death oc-
curred in 4.3 h (2.1 to 6.5 h; mean 195'/, confidence interval]). Patients
who had active life support treatment until death received more support
measures including inotropic agents (36 of 36 vs 21 of 138; p < 0.05).
dialysis (4 of 36 vs 2 of 1 38; p < 0.05). and mechanical ventilation at the
time of death (36of 36vs81 of 138; p< 0.05). Physician differences (>
10-foId) were detected for prescribed do.ses of morphine and sedative
agents whether or not life support was withheld or withdrawn. The me-
dian cumulative dose of morphine prescribed during the final 1 2 h was
larger (fivefold) in patients undergoing withdrawal of life support. No
documented discussion of life support withdrawal was noted in one case.
In the remaining patients, the 10 staff physicians were documented to be
involved in 77% (range. 54 to 94% ) of the end-of-life discussions. CON-
CLUSIONS: Differences were evident in technologic and pharmacologic
support and in physician prescribing habits in patients for whom life
support was or was not withheld or withdrawn. Substantial variability
was noted in physician documentation of physician-family interactions
surrounding the withdrawal of life support.

Managing Life-Threatening Hemoptysis: Has .\nything Really
Changed? Haponik EF. Fein A. Chin R. Chest 200(_) No\;l IS(5l:l43l-
14_^5.

.STUDY OBJECTIVES: To delineate currcnl chest clinicians' approaches
to the management of patients with life-threatening hemoptysis. DE-
SIGN; Survey during a computer-assisted interactive continuing medical
education presentation. SETTING: The 1998 American College of Chest
Physicians (ACCP) Annual Scientific Assembly. PARTICIPANTS: Chest
clinicians attending the respiratory emergency symposium. RESULTS:
Most clinicians (86%) had cared for patients with life-threatening he-
moptysis, and 28% had cared for patients with fatal events during the
previous year. Those clinicians favored management in the ICU setting
(95%) with early endotracheal intubation (85"^; I. and they tended to use
a large-bore, single-lumen endotracheal tube (57%). The majority (64%)
favored the early performance of diagnostic bronchoscopy dunng the
first 24 h. Most clinicians (79%) used the Hexible instrument, a higher
frequency than respondents at a similar symposium on hemoptysis at the
1988 ACCP meeting (48%: p < O.WWl). Most current clinicians (77%)
had experience w ith endobronchial measures to control bleeding, but few
( 14% ) found them to be consistently worthwhile. Chest CT scanning was

440

Rlspiratorv Care • May 2001 Vol 46 No 5

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Abstracts

ol'lcn helpful in diagnosis (55%). In iheir nianagcmcnt of bleeding, half
of these clinicians favored the use of interventional angiography, even in
operable patients, which is a substantial change from 1988 when 2'i'^/c had
favored this approach Ip < O.IKK)!). CONCLUSIONS: During the past
decade, life-threatening hemoptysis has remained an important problem.
Flexible bronchoscopy and interventional angiography have become in-
creasingly established, more widely accepted approaches lo patient care.

A Morphologic Study of l.onj;- lerm Ketcniion of Kluorocarbun Af-
ter Liquid Ventilation— Hood CI. Modell JH. Chest 2000 Nov;l 18(5):
1436-1440.

STUDY OBJECTIVES: To determine how long perlluorinated hydro-
carbons remain in the lung after they are used for lung ventilation in
dogs, and to determine if residual perfluorinated hydrocarbons cause
structural alteration or an inllatnmatory reaction of the lung. DESIGN:
Adult dogs were anesthetized and received \enlilation with oxygenated
pertluorinaled hydrocarbon liquid. Morphologic studies of tissue from
the lungs of these dogs were performed at intervals of a few minutes to
10 years after reconversion lo breathing gas. SETTING: University Col-
lege of Medicine. PARTICIPANTS: Adult mongrel and beagle dogs.
INTERVENTIONS: Anesthetized adult dogs breathed oxygenated liquid
tluorocarbons for 1 h and then were reconverted to breathing air. Three
lluorocarbons. FX-80 (C«F,„0; .3M Company; St. Paul. MN). Caroxin-D
(C„|F,,0,; P-ID; Allied Chemical Company; Morristown. NJl. and Car-
oxin-F (C„F2„0; P-12F; .Mlied Chemical Company), were used. Mor-
phologic studies of the lungs of these animals were performed immedi-
ately after restoration of air breathing and at intervals for up to 10 years.
Not all animals were studied at each time interval. MEASUREMENTS
AND RESULTS: A transient, acute inflammatory reaction was followed
by a massive influx of macrophages, which were at first intra-alveolar
and later interstitial, especially around ves.sels and bronchioles. Fluoro-
carbons remained in the lung in diininishing amounts for at least 5 years,
as evidenced by persistent vacuolated macrophages in the alveoli, inter-
stitiuni. and hilar lymph nodes; lluorocarbon was also detected in these
tissues by chemical assays. In no case was there fibrosis or any other
structural alteration associated with the residual fiuorocarbon. which sug-
gests that it was inert. At 10 years, no evidence of residual fiuorocarbon
was seen morphologically.

Nasal Continuous Positive Airway Pressure Devices Do Not Maintain
the .Set Pressure Dynamically when Tested I'nder Simulated Clinical

Conditions— Bacon JP. Farncy R.I. Jensen RL. \\ alkcr JM. Cloward TV.
Chest 2000 Nov;l 18(5): 144 1-1449.

STUDY OBJECTIVES: Nasal continuous positive airway pressure
(CPAP) is standard therapy for obstructive sleep apnea syndrome. The
effective nasal mask pressure may be adversely affected by factors that
increase system resistance (eg, long tubing and/or water condensation)
and by dynamic variables (breathing frequency [f] and tidal volume
(V^^l). The present study was conducted in order to assess the perfor-
mance of CPAP machines throughout a range of simulated clinical con-
ditions. DESIGN: Four currently used CPAP machines were tested at
settings of 5. 10. 15. and 20 cm H,0 using a pulmonary waveform
generator to produce V,s of 0.4. 0.8. and 1.2 L at frequencies of 10. 20.
and .10 breaths/min. Machines were tested under five conditions: 6-foot
and 12-foot tubing, with and without an in-line humidifier, and 12-foot
tubing with humidifier and water condensation. MEASUREMENTS:
Maximum and minimum mask pressure measurements were obtained
during five respiratory cycles for each dynamic variable under each of the
five conditions and CPAP settings (180 experiments on each of four
CPAP models). RESULTS: Using typical clinical parameters (V,, 0.4 L
and 0.8 L; f. 10 breaths/min and 20 breaths/min; and CPAP. 5 to 15 cm
H,0). mask pressure consislentK varied above and below the set point
when additional tubing and/or a huinidifier were added to the system (0.7

to 2.9 cm H,0 below and 0.5 to 1.0 cm H,0 above the set pressure).
Water condensation caused large pressure deviations (inspiratory pres-
sure ranged from 3.5 to 5.6 cm H,0 below set pressure, and expiratory
pressure ranged from 0.7 to 3.5 cin H,0 above set pressure). CONCLU-
SIONS: Therapy and compliance could be adversely affected because
some CPAP machines in current use do not maintain constant continuous
mask pressure when tested using simulated conditions, especially when
water condenses ni llic Uihing.

Work of Hriathip); During; .Spontaneous \ entilation in \nestheti/ed
Children: A Comparative Study .\niong the Face .Mask, LaryiiKcal
Mask Airway and Kndotracheal Tube — Keidan I. Fine GF. Kagawa T.
Schneck FX. Motoyama EK. Ancsth Analg 2000 Dec;91(6):l381-1388.

Work of breathing (WOB) increases during general anesthesia in adults,
but such information has been limited in pediatric patients. We studied
WOB in 24 healthy children imcan age 2 ± 1.9 yrs). during elective
urogenital surgery under 1 minimum alveolar anesthetic concentration
halothanc-nitrous oxide anesthesia with a caudal block while breathing
spontaneously. WOB was measured with an esophageal balloon, minia-
ture fiowmeter. and a computerized (Bicore) system. In each patient.
WOB was computed under four conditions: a mask without oral airway
(-AW). a mask with oral airway ( -i- AW), a laryngeal mask airway (LMA).
and an endotracheal tube (ETT). With each apparatus WOB was studied
both with continuous positive airway pressure (CPAP) (5-6 cm H,Ol and
without CPAP (or zero end-expiratory pressure |ZEEP|). Under ZEEP.
WOB (g. cm/kg) among the four apparatus were (mean ± SEM): mask
(-AW) (64 i 19.2) > mask (-FAW) (44 ± 17.2). LMA (42 ± 15.6) >
ETT (25.4 ± 12.4) (p < 0.05). WOB with CPAP significantly (p < 0.05)
decreased from WOB with ZEEP in three groups (mask |-AW]. mask
[-t-AW]. and LMA). but not in the ETT group. Tidal volume (both ZEEP
and CPAP) and end-tidal P^o, (with CPAP only) were significantly (p <
0.05) decreased only in the ETT group, whereas no significant difference
was found in respiratory rate or minute volume among the four airway
apparatus groups, either with or without CPAP. The reduction in WOB.
when breathing through ETT was primarily attributable to decreases in
tidal volume and \olume work. The finding that WOB decreases with
CPAP in all groups except for the ETT group suggests that the decrease
is a result of improved patency of the upper airway rather than of in-
creases in functional residual capacity and lung compliance. Implica-
tions: We studied work of breathing (WOB) measured with four airway
devices, with and without application of continuous positive airway pres-
sure (CPAP). Laryngeal mask airway and mask w ith oral airway decrea.se
WOB compared with mask alone. CP.^P decreases WOB with all devices
except the endotracheal tube. Increased WOB appears mostly because of
soft tissue upper airvwiy obstruction.

Auditory Steady-State Response and Bispectral Index for .\ssessing
Level of Consciousness During Propofol Sedation and Hypnosis —

Bonhomme V, Plourde G. Meuret P. Fiset P, Backman SB. Anesth Analg
2000Dec;91(6):1.198-l4()3.

We assessed the effect of propofol on the auditory steady-state response
(ASSR). bispectral (BlSl index, and le\el of consciousness in two ex-
periments. In Experiment 1. propofol was infused in 1 1 subjects to obtain
effect-site concentrations of 1. 2. 3. and 4 jig/mL. The .ASSR and BIS
index were recorded during baseline and at each concentration. The
ASSR was evoked by monaural stimuli. Propofol caused a concentration-
dependent decrease of the ASSR and BIS index values (r = 0.76 and
0.93. respectively; p < 0.0001). The prediction probability for loss of
consciousness was 0.89. 0.96. and 0.94 for ASSR. BIS. and anerial blood
concentration of propofol, respectively. In Experiment 2, we compared
the effects of binaural versus monaural stimulus delivery on the .ASSR m
six subjects during awake baseline and propofol-induced unconscious-
ness. During baseline, the ASSR amplitude with binaural stimulation

442

Respiratory Care • May 2001 Vol 46 No 5

ABSTRACrS

(0.47 ± I .< mV. mean • SO) was signitlcanliy (p < 0.(X)2) larger than
with monaural slimulalion (0.35 ± 0.11 /iVi. Diirinj; uncon^ci^)usncss.
ihc ampliliuli- was 0.(W * ().(W fiV wllh monaural anil 0.06 + 0. 04 >xV
ullh binaural slimulalion iN.S). The prediction probahilily Tor loss of
consciousness was »? (0.04 SH) lor monaural and l.(K) (()(K) SE) for
binaural deliver). We conclude llial (he A.SSR and BI.S index arc allen-
uuled in a concentratiun-dependeni manner by prupolul and provide a
useful measure of lis sedative and hypnotic effect. BIS was easier to u.sc
and slightly more sensitive. The ASSR should be recorded with binaural
stimulation. The A.SSR and BIS index are both useful for assessing the
level of consciousness during sedation and hypnosis with propofol. How-
ever, the BIS index was simpler to use and provided a nuire sensitive
measure of sedation Implications: We have compared tvMi methods for
predicting whether the amount of propofol given to a human subject is
sufficient to cause unconsciousness, defined as failure to respond to a
simple V erbal command. The two methods studied are the auditory steady-
state response, which measures the electrical response of the brain to
sound, and the bispectral index, which is a number derived from the
electroencephalogram. The results showed that both methods are very
good predictors of the level of consciousness; however, bispectral was
easier to use.

.Vspiration in Transtracheal Oxygen Insulllatinn with Different In-
surflalion Flow Kates During Cardiopulmonary Resuscitation in
Dogs — Jaw an li. Cheung HK. Chong ZK. Poon YY. Cheng YF. Chen
HS, et al. Anesih Analg 2(X)0 Dec:91{6):l43l-I435.

We investigated whether transtracheal insufflation of oxygen with dif-
ferent insuftlation fiow rates protects against aspiration of gastric con-
tents during cardiopulmonary resuscitation (CPR). Its ventilation and
oxygenation effects were also evaluated. Cardiac arrest was induced in
anesthetized and paralyzed 1 8 mongrel dogs. Chest compression using an
automatic thumper was performed while the dogs randomly received no
mechanical ventilation (Group I. n = 6) or were transtracheally insuf-
flated with 4 L/min oxygen (Group II, n = 6) or 10 L/min oxygen (Group
III. n = 6). Blood samples were drawn every 5 min for 20 min for blood
gas analysis, the mouths of the dogs were then filled with 70 mL mixed
barium, and 10 min after chest compression, chest radiographs were
taken to evaluate the incidence of pulmonary aspiration. Results showed
that pulmonary aspiration occurred in all dogs of Group 1 and three of the
six dogs in Group 11. whereas dogs in Group 111 were free from pulmo-
nary aspiration. Both transtracheal oxygen insuffiation groups maintained
oxygen saturation significantly better than Group I. but mild hypercapnia
was observed in all groups after 20 min of CPR. We conclude that
transtracheal oxygen insufflation, but not chest compression alone, was
able to maintain oxygenation for 20 min during CPR in dogs with cardiac
arrest. Mild hypercapnia was noted in all groups. Chest compression
alone caused pulmonary aspiration, whereas insufflation of 10 L 0,/min
provided better protection against pulmonary aspiration than thai of 4 L
0,/min. Implications: In case of difficult airway during cardiopulmonary
resuscitation, insertion of an l.V. catheter through the trachea is easy, and
insufflation of 10 L/min of oxygen through the needle can not only
maintain the oxygenation but also prevent aspiration.

Respiratory Efficacy of Subglottic l.oH-Frc(|uency, Subglottic (iim-
hinid-Kre(|uencv. and Siipraglottic ('ombined-Frequcncy .let \ enti-
latinn During Microlarviigeal Surgery Bacher A. l.ang 1. Weber J.
Aloy A. Ancslh Analg 2000 13ec:yi((i): l.S()ft-l.S12.

We tested the respiratory efficacy of different jet ventilation techniques
(subglottic low-frequency versus subglottic combined-frequency and sub-
glottic combined-frequency versus supraglottic combined frequency) in
patients undergoing microlaryngeal surgery. The R,co, ^"J 'he quotient
of arterial oxygen tension (P,„,) over Fm, were incasured. After anes-
thetic induction (propofol. rcmifentanil. vecuronium), an endotracheal

Mon-Jel catheter (Xomcd. Jaek.sonvillc. FL) for subglottic jet ventilation
and a laryngoscope for supraglottic jet ventilation (Carl Reiner G.m.h.H.,
Vienna. Austria) were inserted. In Group I (n = IS), subglottic low-
frequency (I.S breaths/min). combined-frequency (WK) and 15 breaths/
min). and low-frequency jet ventilation was subsequently performed (15
min each). In Group 2 (n = 19). the sequence was supraglottic. subglot-
tic, and supraglottic combined-frequency jet ventilation. The driving pres-
sures were initially adjusted to achieve normocapnia and were not changed
during the entire study period. The F,,,, was measured end<ilracheally.
The Wilcoxon's signed rank lest was applied. In Group I. P,,,,,, •"!''
P„<,,/F|,,, improved significantly after switching from subglottic low-
frequency to subglottic combined-frequency jel ventilation (P^,,),. from
46.6 ± X.3 lo 42. 1 ± 8.1 mm Hg; P,o,/F|„,. from 31 1 ± 144 to 361 ±
141 mm Hg; p <0.05). In Group 2. P,,-,,, increased and P^o,/F|<>, de-
creased significantly after switching from supraglottic to subglottic com-
bined-frequency jet ventilation (P,,co,- ff""! 39.4 ± 7.1 to 45.9 ± 7.5 mm
Hg; P„<),/F|„,, from 415 ± 114 to 351 ± 129 mm Hg; p <0.05). We
conclude that subglottic combined-frequency jet ventilation is less effec-
tive than supraglottic combined-frequency ventilation, but more effective
than subglottic low-frequency jel ventilation. Implications: The combi-
nation of high and low respiratory frequencies (6(K) and 15 brealhs/min)
improves pulmonary gas exchange during subglottic jet ventilation via an
endotracheal catheter. However, subglottic combined-frequency jet ven-
tilation is less effective than supraglottic combined-frequency jet venti-
lation via a jet ventilation laryngoscope.

The KfTects of the Reverse Trendelenburg Position on Respiratory
Mechanics and Blood (Jases in Morbidly Obese Patients During Bari-
atric Surgery — Pcrilli V. Sollazzi L. Bozza P. .Viodesti C. Chierichini A.
Tacchino KM. Ranien R. Anesth Analg 2()(K) Dec;91(6):1520-I525.

Anesthesia adversely affects respiratory function, particularly in mor-
bidly obese patients. Although many studies have been performed to
determine the optimal ventilatory settings in these patients, this question
has not been answered. The aim of this study was to evaluate the effect
of reverse Trendelenburg position (RTP) on gas exchange and respiratory
mechanics in 15 obese patients undergoing biliopancrealic diversion. A
standardized anesthetic regimen was used and patients were examined at
standard limes: 1 ) after tracheal intubation. 2) after laparotomy. 3) after
positioning of subccstal retractors. 4) with retractors in RTP. The mea-
surements of respiratory mechanics were repealed for a wide range of
tidal volumes by using the technique of rapid occlusion during constant
flow infiation. We noted a wide alveolar-arterial oxygen difference
[P(A-a)0,] in all patients, panicularly during Phase 3. When the patients
were placed in RTP. P(A-a)0, showed a significant improvement and a
return toward baseline values. As for mechanics, total respiratory system
compliance was significantly higher in RTP than in the other pha.ses. In
conclusion, our data suggest that RTP is an appropriate intraoperative
posture for obese subjects because it causes n)inimal arterial blood pres-
sure changes and improves oxygenation. Implications: The aim of the
study was to assess whether the reverse Trendelenburg position could
improve pulmonary gas exchange in obese patients undergoing abdom-
inal surgical procedures. Our work may have a clinical value because few
studies deal with this issue

Characlerizaliiin of a Microprocessor-Contnillid liibiilar Multiple
Metered Dose Inhaler Aerosol (ienerator for Inhalation Ixposures
of Pharmaceuticals — Rothenberg SJ. Barnctt JF. Dearlove Gh. Parker
RM. Hall 1)J. Bradv JT. et al. J Aerosol Med 2(KK);1.1(3):I.57-I68.

A microprocessor-controlled tubular multiple metered dose inhaler ( MDI i
aerosol generator was constructed for the delivery of pharmaceutical
aerosols to inhalation chambers. The MDIs were mounted in four cas-
settes containing one to four MDIs on a stepped end plate. The MDIs in
each cassette were pneumatically activated al intervals that were con-

Respiratory Care • May 2001 Vol 46 No 5

44."^

Ahstracts

trolled by the microprocessor. The cassettes permitted easy replacement
of each set of MDIs with a fresh set of MDIs whenever necessary.
Aerosol concentration was controlled by varying the number of active
MDIs in each cassette and the frci|uency of activations per minute of each
row. Aerosol from the MDK tlowed along the lonj; axis of the tube,
which provided a path length sufficient to diminish impaction los.ses.
Using a light-scattering device to monitor the aerosol concentration, the
pulsatile output from the .MDIs in the cassclles was demonstrated to be
adequately damped out provided that the dilution/mi.\ing/aging chamber
exceeded 3 ft in length. The tube diameter selected was the minimum
compatible with mounting the required number of MDIs so that the linear
velocity of the aerosol was adequate to efficiently transport the aerosol
out of the dilution chamber. Aerosol concentration and panicle si/c data
v^ere recorded for a nose-only rodent exposure chamber. Reproducible
aerosol concentrations ranging from 0.0.'^ to 0.6 nig/L were generated.
Particle sizes ranged from 2- to .Vmum mass median aerodynamic di-
ameter. Thus, the aerosol generated was within Ihe size range suitable for
inhal.ilion exposures.

simulation, and the errors were assessed. An iterative method was used
to correct for the partial volume effect, and its effectiveness in imprm ing
errors was evaluated. The errors were compared with those of planar
imaging. The precision of measurements was significantly better for
.SPECT than planar imaging (2.8 vs 6..17< for total lung activity. 6 vs 20%
for PI. and 3 vs fi'i for relative PI I. The method of correcting for the
intluence of the partial volume effect signillcanlly improved the accuracy
of PI evaluation without affecting precision. SPECT is capable of accu-
rate and precise measurements of aerosol distribution in the lung, which
are improved compared with those measured by conventional planar
imaging. A technique for correcting the SPECT data for Ihe influence of
the partial volume effect has been described. Simulation is demonstrated
as a valuable method of technique evaluation and comparison.

Respiratory -Related Quality of I. Ho: Relatiiin to Pulmonary Func-
tion, lunclional Kxereist (.'apacity. and .Sputum Kiophysieal Prop-
erties — Piquctle CA. Clarkson L. Okaniolo K. Kmi JS. Ruhni BK. J
Aerosol Med 2O0O;l3(3):263-272.

\n In\esti}:alion of the Solubility of Various Compounds in the Hy-
dronuoroalkane Propellanis and Possible Model Liquid Propellants —

Dickinson PA. .Seville PC. McHale H. Perkins NC. laylor G, J Aerosol
Med 2(K)0; 1 3(3): 179-1X6.

The aims of this study were to investigate descriptive parameters that
may predict the solubility of compounds in the hydiolluoroalkane (HFA)
propellanis and to identify a model HFA propcUant that is liquid at room
temperature and atmospheric pressure. The solubility of 32 and 20 com-
pounds chosen to give a wide range of physicocheinical properties in
HFA- 134a and HFA-227. respectively, was measured. The Fedors solu-
bility parameter and a computed log octanol water partition coefficient
(CLOGP) were compared with the compounds' solubility in the HFA
propellants. A total of 19 and \5 solutes had finite solubilities for HF.'\-
134a and HFA-227. respectively, although the remaining .solutes were
miscible in all proportions. There was no apparent relation between sol-
ubility in HF.A and the Fedors solubility parameter. This was not im-
proved by considering the hydrogen-bonding potential of the compounds.
When log solubility versus CLOGP was plotted, there was a linear re-
lation for 16 and 12 of the compounds exhibiting a finite solubility in the
HFA propellants, although four solutes (phenols) were displaced to the
left of the linear relation. The remaining 3 compounds had much lower
solubilities than was predicted from their CLOGPs. possibly as a conse-
quence of their crysiallinity (high melting point-.). Of the putative model
propellants investigated (i.e.. perfiuorohexane (PFH). IH-perfiuorohex-
anc I IH-PFH). and 2,2,2-lrifiuoroethanoll, IH-PFH was the most prom-
ising, with a linear relation between solubility in IH-PFH and solubility
in HFA propellant being observed. The solubilities in IH-PFH were
approximately 1 1 and 26% of those in HFA-I34a and HFA-227.

Evaluation of the .Accuracy and Precision of Lung Aerosol Depo.si-
tlon Measurements from .Single-Photon F.niission Computed Tomog-
raphy I sing Simulation — I loming .IS. Sauicl \ . Conu.i\ Jll. Ilolgalc
ST. Bailey AG, Marloncii TB. .1 .Aerosol Med 20(10; 13(3): 1X7- 198.

Single-photon emission computed tomography (SPECT) imaging is be-
ing increasingly used to assess inhaled aerosol deposition. This study
uses simulation to evaluate the errors involved in such measurements and
to compare them with those from conventional planar imaging. SPECT
images of known theoretical distributions of radioaerosol in the lung have
been simulated using lung models derived from magnetic resonance stud-
ies in human subjects. Total lung activity was evaluated from the siinu-
lated images. A spherical transform of the lung distributions was per-
formed, and the absolute penetration index (PI) and a relative value
expressed as a fraction of that in a simulated ventilation image were
calculated. All parameters were compared with the true value used in the

One of the difficulties in assessing mucoactive therapy is selecting clin-
ical outcome variables that reflect the impact of clearing airway secre-
tions on quality of life (QOL). Petty and colleagues developed a ques-
tionnaire designed to evaluate the clinical impact of mucoactive therapy
in patients with chronic bronchitis (CB). We evaluated this questionnaire
in a multicentcr study of a mucolytic medication used in patients « ith CB
and hypothesized that spirometry, exercise capacity, and spuluni clear-
ability changes would correlate with QOL changes. This was a multi-
center trial in 159 patients with stable CB (III completed the 16- week
study). Spirometry, plethysmography, the 6-minute walk test (6MWT),
and Petty score as a measure of QOL were assessed at each visit. Sputum
was collected at each visit. Cough transportability was measured in a
cough machine, and mucociliary transportability was measured on the
frog palate. Cohesivity was measured in a filancemeter. interfacial ten-
sion by de Nouy ring, and wettability by contact angle analysis. Within
the entire data set of 694 evaluations, there was no correlation between
pulmonary function and QOL. There was an inverse correlation with
di.stance covered in a 6MWT (R- = 0.041, p < 0,0001). Sputum CTR
was directly correlated with QOL (R- = 0.027, p < 0.0001). Change
from baseline (mean of first three visits) was computed and compared the
change in the mean of values at the 8- and 12-week visits (n = 108 sets
of data pairs). This was analyzed as a percentage of change for contin-
uous measurements, and as QOL is normative, we calculated the absolute
change in QOL. There was no relation between QOL and 6MWT changes.
There was an inverse relation between change in forced expiratory vol-
ume in 1 .second and QOL (R- = 0.092, p = 0.0021 1 as well as between
forced vital capacity and QOL (R- = 0.05. p = 0,024), There was a direct
relation between CTR and QOL (R- = 0,039, p = 0,048), The relation
between QOL and 6-minute walk distance was expected but weak. The
consistent relation between CTR and QOL (suggesting that improved
CTR of sputum is associated with decreased QOL) is difficult to explain.
A change in forced expiratory viilume in I second and forced vital
capacity did correlate with a change in QOL. There is a need for a good
QOL tool to evaluate mucus clearance dev ices or medications. The Petty
questionnaire was designed specifically for this task, but the effect on
sputum properties by current mucoactive agents may be too small to elicit
a significant change in the Petty score.

Measuring Lung Function in Infancy — Lucas JS. Foreman CT. Clough
JB. Respir Med 2()()() Jul;94(7):641-647.

.Mthough the earliest reliable lung function tests in infants were per-
formed as long as 40 years ago. there has only recently been a growth in
this area, as simpler methods and better equipment and IT resources have
been developed. Exciting information is accumulating about the nonnal
physiology and pathology of the infant lung. Many basic questions are

444

Respiratory Care • May 2001 Vol 46 No 5

An Innovative Television Special

Worldwide Focus on

COPD:

^;r

Coming Up For Air cordis an umbrella term used to describe major lung

diseases where airflow Is reduced Including emphysema

and chronic bronchitis. The result Is lots of coughing, shortness of breath, chest tightness
and Increased mucus production. And in severe cases, less oxygen and more carbon
dioxide. Smoking Is the culprit for 90 percent of all cases of COPD.

Nearly half of the people diagnosed with COPD get short of breath while doing such
mundane things as washing, dressing or doing light housework. A third get breathless just
having a conversation or sitting or lying down.

The symptoms of COPD are globally under-recognized and sufferers of this condition tend to
underestimate the severity of their symptoms. Do you have the symptoms''

COPD: Coming Up For Air, co-hosted by Stephen L. Rennard, IVI.D., Larson Professor of
Medicine at the University of Nebraska fvledical Center and James F. Donahue, M.D.,
Professor of Medicine at the University of North Carolina raises awareness of this under-
reported illness.

WehMD

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Abstracts

slill unanswered ;hkI llic ;il'iilil\ In porlorrn iIk'm' le^l^ renuins Liinluiod
to ;i lew speciali/eil ceiUies. I'd co-ordiriate the developnienl iil ILIT and
establish standardi/atlon in a number iil areas incUidini: measuremenl
eondilions, eiiuipnient speeilleatinns. melhodoUigy proloeols and data
analysis, inlernatinnal eollaboration is neeessary between the teams work-
ing in this field (Table 5). Collaborative groups arc currently addressing
these issues and are also developing recommendations regarding the
design of randomized clinical trials, multi-centre studies and research
agendas. Infant lung function testing remains primarily a research tool.
Our aim should be not only to refine and develop the techniques of
physiological measurement but to apply ILFT to the objective study of
respiratory illness in infants in the clinical setting so as to aid in the
prevention and ireatnienl of these common, debilitating and costly dis-
eases.

CumpariMiii of High and Low Dose of (he Inhaled Sleriiid, Uudvs-
onide. .^s an Initial Treatment in Newly Delected .Asthma — Tuki-
ainen H. Tai\ainen A. Majander R, Poussa T. .Svahn T, Puoli|oki H.
Terho EO. Respir Med 2000 Jul;y4(7):678-683.

The importance of early initiation of inhaled steroids even in mild asthma
has been documented in several studies. It is not. however, clear whether
the treatment should be started w ith a high or a low dose of the inhaled
steroid. We have compared the effects of high and low dose inhaled
steroid, budesonide. in patients with newly detected asthma. We studied
101 adult patients with newly detected bronchial asthma who were with-
out inhaled steroid or any regular pharmacological treatment for their
asthma. The patients were randomly allocated to two treatment groups:
one to receive SOO niicrog inhaled budesonide per day and the other to
receive 200 microg inhaled budesonide per day. The drugs were given
with a Turbuhaler dry powder inhaler. During the .'5-month treatment
period, no significant differences between the treatment groups were
noted in morning or evening PEF values, in spironietric parameters, in
asthmatic symptoms or in the use of rescue /3,-agonists. The decrease in
bronchial hyperresponsiveness was, however, more marked in the high
dose budesonide group, reaching a borderline significance (p = 0. 10 high
vs. low dose budesonide). In addition, in serum markers of asthmatic
innammation significant differences were shown between the treatment
groups. The decrease in the number of blood eosinophils during the
treatment was more marked in the high dose budesonide group (p = 0.02;
high \s. low dose budesonide). In serum ECP no change was observed In
the low dose budesonide group, but a marked decrease in the high-dose
budesonide group (p = 0.00S; high vs. low dose budesonide). The change
was even more marked with regard to serum EPX (p= 0.005: high vs. low
dose budesonide). Our results support the view that the treatment of
newly detected asthma should be started with a high dose of inhaled
steroid. The low dose may not be enough to suppress asthmatic Innam-
mation despite good clinical primary response.

were gl\cn alcohol to drink, ihe i|uanm\ based upon body weight. .Mter
a gap of at least 20 min. subjects were asked to pro\ ide evidential breath
samples in accordance with the test procedure built Into the I. Ion lnto\l-
ly/er 60()0UK. The results showed that two asthmatic subjects, four with
COPD and three with restrictive lung disease failed to provide evidential
breath samples even after four attempts. Despite the device requiring a
minimum sample volume of 1.2 L. eight of the nine subjects who failed
had a forced vital capacity (FVC) of more than 1 .5 L. Seven of these nine
subjects had a forced expiratory volume in 1 sec (FEV,) of less than 1.0
L. In conclusion, this study has shown that some subjects with lung
diseases may have difficulty in providing evidential breath samples using
the Lion lnUi\lly/cr 6000 UK.

Maviinal InspiratorN Mouth Pressures (I'IM.W) in Healthy Sub-
jects: What Is the Lower Limit of Normal? Hauimann H. Hefele S,
Scholtcn K. Huber RM. Respir Med 2(K)0 Jul;y4(7):689-6y3.

BACKGROUND: Maximal inspiratory mouth pressures are suitable for
non-invasive evaluation of respiratory muscle function. Different studies
on PIMAX give predicted normal values and their relation to anthropo-
metric data. Due to a large inter-subject variation of PIMAX. predicted
values. howe\er. maximal inspiralory mouth pressures are not suitable to
define the Individual expected normal PIMAX. What is the lower limit of
the normal range? METHODS: PIM.AX has been prospectively measured
in a representative sample of 504 healthy volunteers (248 males and 256
females) between 18 and 82 years of age with normal lung function. Age.
height, weight, body mass index (BMI) and smoking status were re-
corded and Incorporated stepwise in a multiple regression analysis to
determine prediction equations. Lower limits of the normal range were
defined as the fifth percentile of the residuals derixed from the regression
model. RESULTS: Mean values of PIMAX were 9.95 kPa for men and
7.43 kPa for women. Significant correlations were found with height,
weight. BMI. FEV,. PEF and FVC (p<0.0l). The strongest correlation
appeared with sex and age (p<0.0OI ). Smoking status and smoked pack-
years were not independent predictors of inspiratory pressures. Lower
limits of normal were 59'7( for women and 609t for men of the predicted
PIMAX. CONCLUSIONS: In the Interpretation of maximal inspiratory
mouth pressures, normal values should represent the lower limit of the
noniial range derived from the regression model in order to avoid false
pathological results. Prediction equations as well as lower limits of nor-
mal resulting from a study cohort of healthy 18-82-year-olds are given
and are recommended to be used by pulmonary function laboratories In
young and old patients.

Airway Obstruction and Chronic Exertional Dyspnoea in Patients
with Persistent Bronchial Asthma — Fllippelll M. Pacini F. Romagnoli
1, Rosi E. Otlanclh R. Duranli R. Scano G. Respir Med 2000 Jul;y4(7):
694-701.

.\ Study to Investigate the .Vbility of Subjects with I'hronic Lung
Diseases tii Provide Evidential Breath Samples Using the Lion In-
loxilj/er (i(tO(l Uk Breath Alcohol lesting Device- Iluncybournc D,
Moore AJ, Buttertleld AK, Azzan L. Respir Med 2000 Jul;94(7):684-
688.

The Lion Inloximeter .3000 has been used for evidential breath testing in
the U.K. for some years. Some individuals with lung diseases have dif-
ficulty In providing evidential breath samples using the device. This
study describes an investigation that we have carried out on a newer
inslnimenl-the Lion Inloxilyzer 60(X)UK-which is now in use in the
U.K. The study was designed to investigate the ability of subjects with a
variety of lung diseases to provide evidential breath samples using this
device. The 40 adult subjects investigated comprized 10 normal controls.
10 with asthma. 10 with chronic obstructive pulmonary disease (COPD)
and 10 with restrictive lung disease. After baseline spirometry, subjects

In patients with COPD. fiow hniltatlon (FL) predicts chronic exertional
dyspnoea (CED) better than routine spirometry. Whether, and to what
extent, FL and CED are overlapping quantities in chronic asthma has not
yet been defined. Forty consecutive clinically stable asthmatic patients
without smoking history or cardiopulmonary disorders, were studied. In
each subject respiratory function, including static and dynamic pulmo-
nary volumes, was evaluated; maximal (MEFV) and partial iPEFV) ex-
piratory Y-V curves and isovolumic partial to maximal flow ratio (M/P).
FL was assessed in a seated patient by comparing tidal and PEFV curves:
FL was detected when tidal Hows were superimposed or exceeded those
obtalncil during PEFV curves, and was expressed as a percentage of the
expired control tidal volume (V,) affected by flow limitation i.FL9c V, ).
Dyspnoea was assessed by both MRC scale and Baseline Dyspnoea
Index (BDl) focal score. Half of the patients were found to have FL. They
were older, more dyspnoeic and more obstructed (p<0.03 - p<0.000005)
than the non-FI. group. FEV,. vital capacity ( VC). age. body mass index.

446

Respiratory Care • May 2001 Vol 46 No 5

Sd^Ccf cteaclCme Tftacf 31 , 2001
7 mat deaciUtte ^uCcf 17 , 2001

FL and M/P ratio were all related to dyspnoea scores. FL was signifi-
cantly related to FEV, (r = - 0.59). Multiple regression analysis showed
that FEV, (p = 0.00.'!. r^= IS-J'J and p = 0.004. r^= 20.3'7r) and age
(p = 0.0(X)6. r- = 26.8?^ and p = 0.016, r = 11%) independentU
predicted a part of the variance of MRC (p = 0.0001. r = 42.17r) and
BDI (p = 0.0008. r^ = 31.3%), respectively. With dyspnoea scale being
the gold standard, diagnostic accuracy (sensitivity and specificity) by
ROC (receiver operating characteristics) analysis was similar for FEV,
and FL. The results indicate that FL may be present in this subset of
asthmatics. CED may not he easily explained by abnormalities of routine
spirometry or FL. the largest part of the CED variance remained unex-
plained. Thus, routine spirometry . FL and CED in patients with bronchial
asthma are only partially overlapping quantities which need to be as-
sessed separately.

Inhaled Nubuli/id Xdrinalinc Improves l.ung Function in Infants
with .Acute Bronchiolitis -Lodrup Carlsen KC. Carlsen KH. Rcspir
Med 2000 Jul;94(7):709-714.

P2-agon'sls ha\e questionable symptomatic effect in infants with acute
bronchiolitis, whereas inhaled, nebuli/cd racemic adrenaline, commonly
used in Norway, appears (clinically) lo be effective. Limited lung func-
tion observations during acute bronchiolitis exists, and less for assessing
possible effects inhaled adrenaline. In this preliminary study, tidal llow-
volume loops were measured in 16 infants with acute bronchiolitis and
seven healthy controls (mean age 7.9 and 4.4 months, respectively), with
repeated measurements \5 min after inhaled nebulized racemic adrena-
line (4 mg diluted in 2 mL saline) in nine bronchiolitis patients. The ratio
of time to reach peak tidal expiratory flow to total expiratory time(tPTEF/
tE) was significantly reduced in children with acute bronchiolitis (mean.
95% CI) (0.08. 0.05-0.10) compared to controls (0.31. 0.18-0.43). with
significant improvement after inhaled racemic adrenaline 0.19 (0.13-

0.25). parallel with significant clinical improvement. Lung function
(tPTEF/tE) was reduced in infants uith acute bronchiolitis and improved
significantly after inhaled racemic adrenaline. Inhaled racemic adrenaline
IS potcniialh an important alteniative for treating infants with acute
bronchiolitis.

Effectiveness of a Clinical Pathway for Inpatient .\sthina Manage-
ment—Johnson KB. Blaisdcll CJ. Walker .A. Eggleston i'. Pedialncs
2000 Nov;106(5):1006-1012.

BACKGROUND: Clinical pathways for asthma are tools that have the
potential to improve compliance with nationally recognized management
guidelines, hut their effect on patient outcomes has not been documented.
OBJECTIVES: To determine the effect of an asthma clinical pathway on
patients' length of stay, use of nebulized beta-agonist therapy while
hospitalized, and use of acute care clinics for 2 weeks after discharge.
DESIGN/METHODS: The study was a randomized, controlled trial. Pa-
tients between the ages of 2 and 18 years admitted with an asthma
exacerbation and not under the care of an asthma specialist were eligible
for the study. Patients were randomized either lo a conventional ward
(control group) or to a ward using the clinical pathway (intervention
group). For 2 weeks after discharge, we collected data to determine
whether patients visited a health care provider for worsening asthma.
RE.SULT.S: One hundred ten patients (Ib'/i) were enrolled. Control and
intervention groups had similar demographic and asthma severity pro-
files. The intervention group had an average length of stay 13 hours
shorter than did the control group. In addition, at every dosing interval,
the intervention group received less nebulized beta-agonist therapy. There
were no deaths in either group. CONCLUSION: A clinical pathway for
inpatient asthma decreased the length of stay and bela-agonisi medication
use w ith no ad\erse outcomes or increased acute-care encounters through
2 weeks alter discharge.

Respiratory Care • May 2{)()1 Vol 46 No 5

447

Abstracts

Ri'spirulon SMiiplonis in Mdlluis ot \()uiin Cliildrrii il Ari.) II,
Gillespie B. l-o\maii H PaliuIrKs :()()() NovJ(Ki(5): 1013-1016.

OBJKCTIVKS: Children receiving eliikl care imtside ihe home are al
greater risk ol upper respiratory infeetiiin. bin whether parents of those
children are also al increased risk is undocumented. We describe the
incidence of 2 or more respiratory symptoms in the previous 2 weeks
among 1S5 mothers of children 3 years of age or younger by child care
use. METHODS: Mothers in Michigan and Nebraska were interviewed
by phone regarding respiratory symptoms, use of outside child care (lor
an index child I. sleeping habits, and demographic information. RESULTS:
Nearly one half (4(i..S':r l reported 2 or more symptoms during the past 2
weeks; 15.19! had contacted a health care provider and I.^.OVr spent I or
more days in bed because of their symptoms, w hich lasted an average of
5.5 days. Prevalence of symptoms was invariant to sociodemographic
characteristics. Mothers using outside child care (74.6%) were twice as
likely as those without outside care to have been ill in the past 2 weeks
(odds ratio: 2.26; 95% confidence interval |CI|: 1 . 1 2.4.54). Most mothers
(69.2%) reported having their sleep interrupted by their children at least
once in the last 2 weeks or sharing a bed with a child part or all of the
night (61.1%); 25.4% slept 6 hours or less nightly. Women reporting that
they rarely or never felt rested (26. 5%) were 2.65 times more likely to
be ill (95% CI: 1.26.5.55). compared with those reporting that they
frequently or always felt rested (46.5%). after adjusting for any outside
child care. CONCLUSIONS: Future studies should focus on risk factors
that can be modified to reduce illness among both children and their
parents.

Can Epinephrine Inhalatiiins Re Substituted for Epinephrine Injec-
tion in Children at Risk for .Systemic .Anaphylaxis? — Simons FE. Gu
X. Johnston LM. Simons KJ. Pediatrics 2000 Nov; 106(5): 1040-1044.

B.ACKGROUND: For out-of-hospital treatment of anaphylaxis, inhala-
tion of epinephrine from a pressurized metered-dose inhaler is sometimes
recommended as a noninvasive, user-friendly alternative to an epineph-
rine injection. OBJECTIVE: To determine the feasibility of administer-
ing an adequate epinephrine dose from a metered-dose inhaler in children
at risk for anaphylaxis by assessing the rate and extent of epinephrine
absorption after inhalation. METHODS: We performed a prospective,
randomized, observer-blind, placebo-controlled, parallel-group study in
19 asymptomatic children with a history of anaphylaxis. Based on the
child's weight. 10. 15. or 20 carefully supervised epinephrine or placebo
inhalations were attempted. Before dosing, and at intervals from 5 to ISO
minutes after dosing, we monitored plasma epinephrine concentrations,
blood glucose, heart rate, blood pressure, and adverse effects. RESULTS;
Eleven children (mean ± standard error of the mean; 9 ± 1 years and
33 ± 3 kg I in the epinephrine group were able to inhale 1 1 ± 2 (range:
3-20) puffs, equiv alent to 74% ± 7% of the precalculated dose or 0.078 ±
0.009 mg/kg. They achieved a mean peak plasma epinephrine concen-
tration of 1822 ± 413 (range: 230-4518) pg/mL at 32.7 ± 6.2 minutes.
Eight children ( 10 ± 1 years of age and 33 ± 5 kg) in the placebo group
were able to inhale 12 i 2 (range: 8-20) puffs. 89% i 3% of the
precalculated dose, and had a peak endogenous plasma epinephrine con-
centration of 1316 :t 247 (range: 522-2687) pg/mL at 44.4 ± 16.7
ininutes. In the children receiving epinephrine compared with those re-
ceiving placebo, mean plasma epinephrine concentrations were not sig-
nificantly higher at any time, mean blood glucose concentrations were
significantly higher from 10 to 30 ininutes. mean heart rate was not
significantly different at any time, and mean systolic and diastolic blood
pressures were not significantly increased at most times. .After the inha-
lations of epinephrine or [Tiacebo. the children complained of bad taste
and many experienced cough or dizziness. After inhaling epinephrine. I
child developed nausea, pallor, and muscle twitching. CONCLUSIONS:
Despite expert coaching, because of the number of epinephrine inhala-
tions required and the bad taste of the inhalations, most children were

unable lo inhale siilTicieiit epinephrine to increase llicir plasma epineph-
rine conccnlialions promptly and significanlly. Thcrelore. we urge cau-
tion in recommending epinephrine Inhalation as a substitute for epineph-
rine injection lor out-ol-hosphal Ireatmenl of anaphylaxis symptoms in
children.

Fur^oin;; Life-Sustaining Medical Treatment in .Abused Children

Pediatrics 2(XX) Nov;106(5);l 151-1 153.

A decision to forgo life-sustaining medical treatment (LSMTl for a crit-
ically ill child injured as the result of abuse should be made using the
same criteria as those used for any critically ill child. The parent or
guardian of an abused child may have a confiict of interest when a
decision to forgo LSMT risks changing the legal charge faced by a
parent, guardian, relative, or acquaintance from assault to manslaughter
or homicide. If a physician suspects that a parent or guardian is not acting
in a child's best interest, further review and consultation should be sought
in hopes of resolving the conflict. A guardian ad litem who will represent
the child's interests regarding LSMT should be appointed in all cases in
which a parent or guardian may have a conflict of interest.

Effects of Nasal Continuous Positi\c .Airway Pressure on Soluble Cell
Adhesion Molecules in Patients with Obstructive Sleep Apnea .Syn-
drome — Chin K. Nakamura T. Shimizu K, Mishima M. Nakamura T.
Miyasaka M. Ohi M. Am J Med 2000 Nov;109(7);562-5657.

PURPOSE; Obstructive sleep apnea syndrome is common in middle-
aged men and may be associated with an increased risk of cardiovascular
disease. We investigated the effect of nasal continuous positive airway
pressure (CPAP) treatment on levels of soluble cell adhesion molecules-
which have been shown to be associated with the development of ath-
erosclerosis-in these patients. SUBJECTS AND METHODS: We studied
23 patients with obstructive sleep apnea syndrome diagnosed by poly-
somnography who were treated with nasal CPAP. Serum soluble inter-
cellular adhesion molecule- 1 , E-selectin. and vascular cell adhesion mol-
ecule- 1 levels were measured before nasal CPAP was started, and after 3
or4days(n = 19). 1 monthtn = 23). or 6 months (n = 1 1 ) of treatment.
RESULTS: After 3 to 4 days of nasal CPAP therapy, the mean ( ± SD)
soluble E-selectin level had decreased from 89 ± 44 ng/mL to 69 r 28
ng/niL (p = 0.002). After 1 month, the soluble intercellular adhesion
molecule-l level had decreased from 311 ± 116 ng/mL to 249 ± 74
ng/mL (p = 0.02). After 6 months, soluble vascular cell adhesion mol-
ecule-l levels had not changed significantly, while the mean soluble
intercellular adhesion molecule- 1 level (212 ± 59 ng/mL) had decreased
further (p = 0.02). Before treatment, soluble intercellular adhesion mol-
ecule-l levels and the apnea and hypopnea index were correlated (r =
0.43. p = 0.04).CONCLUSIONS: Obstructive sleep apnea and hypopnea
have a significant ud\erse effect on serum soluble cell adhesion molecule-l
levels that may be reduced b\ nasal CPAP treatment.

Evaluation of a New Module in the Ccmtinuous Monitorin}; of Re-
spiratory Mechanics — Nuncs S. Takala J. Inlcnsne Care .Med 2000
Jun:26(6):670-678.

OBJECTIVE: Bedside monitoring of respiratory mechanics facilitates
the use of lung protective ventilation in acute lung injury (ALI). We
evaluated a new clinical monitor of respiratory mechanics. DESIGN:
Prospective, in vitro and in vivo stud). SE'rilNG: University hospital.
PATIENTS; Measurements were d<ine using a lung model and in patients
after cardiac surgery (n = lOl and in patients with .ALI (n = 10). IN-
TERVENTIONS AND MEASL'REMENTS: The monitor provides con-
tinuous monitoring of pressure, flow and volume waveform and loop
data, and automatically collected variables of respiratory mechanics.
Breath-by-breath respiratory mechanics data and the automated variables
obtained with the ne« monitor were compared with flow and pressure

448

Respiratory Care • Ma'i- 2001 Vol 46 No 5

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Abstracts

reference dala. RESl'LTS: Wavcloriii dala comparison showed errors oi
less ihan S'/r lor most variables. Automatically recorded respiratory pres-
sures and volumes showed good agreement within clinical standards
when compared to reference (errors from 2.59c to 6.2%). Automatically
recorded derived variables present poor agreement (errors from 8.1% to
158.39r). CONCLUSIONS: The waveform data of the new monitor is
accurate. The value of the automatically derived variables is limited by
the tact that inspiratory plateau pressure and plateau compliance liave no
direct physiological meaning. Nevertheless, in clinical monitoring much
information can be derived from the wavelorm signals alone and from
pressure-volume and llow-volume loops. These facililalc nionilming
changes in respiratory mechanics in the ALI patient.

The I'lTeel of lung Injury and I'Acessive lung Fluid, on Impedance
Cardiac Output Measurenienls. in the Crllically III — Ciilchlc) 1 .\,
Calcrofl RM. Tan PY, Kcw J. Cntchlcy .lA. Intensive Care Med 2000
Jun;26(6l:679-685.

OBJECTIVES: To investigate the relationship between the attenuation of
impedance cardiac output (1C^„) measurements and lung fluid content in
critically ill patients. DESIGN: Observational study. SETTING: Inten-
sive Care Unit of a major teaching hospital in Hong Kong. PATIENTS:
Twenty-four critically ill patients who required a pulmonary artery cath-
eter. MEASUREMENTS AND MAIN RESULTS: Triplicate Ihermodi-
lution cardiac output (TD^.„) and BoMed NCCOM.3 <1C,„) measurements
were made simultaneously on a single occasion in each patient. Lung
fluid accumulation was assessed by: (a) thoracic impedance (Zo), (b)
radiological assessment of chest x-rays using an alveolar consolidation
score (0-4) and (c) scoring the degree of hypoxia and use of positive
end-expiratory pressure (PEEP). Offsets (TD^,„-IC^„)/TD^„, expressed as
percentage, were compared with these indices of excess lung fluid. Pa-
tients were di\ided into those with sepsis (n = 13), fluid balance prob-
lems (n = 5) and cardiothoracic problems (n = 6). Mean cardiac output
values were: 6.7 L/min TD^.„ (range 3.6-12.9) and 5.2 L/min IC^„ (range
2.7-9.0). Overall the TD^„ and 1C^.„ values showed great variance, with a
bias and limits of agreement of 1.49 ± 4.16 L/min, or ± 69%. In septic
patients, increasing offset was correlated with decreases in Zo (r = 0.73,
p = 0.005) and increases in alveolar consolidation score (r = 0.72, p =
0.005). CONCLUSIONS: The BoMed under-estimates cardiac output in
critically ill patients. In septic patients the degree of attenuation of 1C^,„
can be related to the extent of lung injury and fluid accumulation within
the thorax.

Failure of a Brief Educational Program to Improve Interpretation of
Pulmonary .Artery Occlusion Pressure Tracings — Zarich S, Pust-Mur-
cone J. Amoateng-Adjepong Y. Manthous CA. Intensive Care Med 2000
Jun;26(6i:698-703.

OBJECTIVE: To determine whether a brief educational program can
reduce variability of interpretation of pulmonary artery occlusion pres-
sure (PAOP) tracings. DESIGN: Prospective, observational study. PAR-
TICIPANTS: Twenty-three intensive care nurses and 18 physicians. IN-
TERVENTIONS: Participants interpreted PAOP tracings before and 1
week after receiving a single, brief educational session and/or written
materials ("in-service") designed to reduce interobserver variability of
PAOP interpretation. Differences between two reference values before
and after in-service (mean population and Chief of Critical Care's read-
ings) were compared for both groups. RESULTS: There were no signif-
icant differences in the variabilities in PAOP interpretations before and
after in-service in either group. CONCLUSIONS: We conclude that this
specific educational program was ineffective in reducing variability of
interpretation of PAOP tracings. These data suggest that more compre-
hensive educational tools and/or sustained programs may be required to
improve performance of critical care personnel in P.AOP interprctalitin

( omparison nf a Specialist KetricNal leani Hilli Current Lnited
Kingdom Practice for the Transport of Critically III Patients — Bell
ingan G, Oluicr I. Bat-son S, Webb A. Intensive Care Med 2()(K) Jun;
26(6):740-744.

OBJECTIVE: The intei-hospital transfer of critically ill patients in the
United Kingdom is commonly undertaken using standard ambulance
under junior doctor escort, despite recommendations for the use of spe-
cialist retrie\al teams. Patients are transferred into University College
London Hospitals (flCLH) intensixe care unit (ICU) by both methods.
We undertook to evaluate the elTect of transfer method on acute physi-
ology (within 2 h of ICU admission) and early mortality ( < 12 h after
ICU admission). DESIGN: Retrospective review of all transfers over I
year. SETTING: UCLH ICU. SUBJECTS: 259 transfers; 168 by spe-
cialist retrieval team (group A) and 91 by standard ambulance with
doctor provided by referring hospital (group B). INTERVENTIONS:
None. MAIN OUTCOME MEASURES: Acute physiology (pH, P,„,,
Paco,- heart rate (HR). mean arterial blood pressure (MAP). 24 h severity
of illness scores (AP.ACHE II. SAPS 111. length of stay and mortality.
RESULTS: There were no differences in demographic characteristics or
severity of illness between the two groups; nevenheless signiflcantly
more patients in group B than in group A were severely acidotic (pH <
7.1: 1 1% vs. 3%, p < 0.008) and hypotensive (MAP < 60: 18 % vs. 9%,
p < 0,03) upon arrival. In addition, there were more deaths within the
first 12 h after adinission with 7.7 % deaths (7/91) in group B transfers
vs. 3% (5/168) in group A. CONCLUSIONS: The use of a specialist
transfer team may significantly improve the acute physiology of critically
ill patients and may reduce early mortality in ICU.

Lung Recruitment and Lung \ olunie Maintenance: .\ Strategy for
Improving Oxygenation and Preventing Lung Injury During Both
Conventional Mechanical Ventilation and High-Frequeney Oscilla-
tion — Rimensberger PC, Pache JC, McKeriie C, Frndova H, Cox PN.
Intensive Care Med 2000 Jun;26(6):745-755.

OBJECTIVE: To determine whether using a small tidal volume (5 niL/
kg) ventilation following sustained inflation with positive endexpiratory
pressure (PEEP) set above the critical closing pressure (CCP) allows
oxygenation equally well and induces as little lung damage as high-
frequency oscillation following sustained inflation with a continuous
distending pressure (CDP) slightly above the CCP of the lung. MATE-
RIAL AND METHODS: Twelve surfactant-depleted adult New Zealand
rabbits were ventilated for 4 h after being randomly assigned to one of
tw o groups: group 1 , conventional mechanical ventilation, tidal volume
5 niL/kg, sustained inflation followed by PEEP > CCP; group 2. high-
frequency oscillation, sustained inflation followed by CDP > CCP. RE-
SULTS: In both groups oxygenation improved substantially after sus-
tained inflation (p < 0.05) and remained stable over 4 h of ventilation
without any differences between the groups. Histologically, both groups
showed only little airway injury to bronchioles, alveolar duets, and al-
veolar airspace, with no difference between the two groups. Myleoper-
oxidase content in homogenized lung tissue, as a marker of leukocyte
infiltration, was equivalent in the two groups. CONCLUSIONS: We
conclude that a \olume recruitment strategy during small tidal volume
ventilation and maintaining lung volumes above lung closing is as pro-
tective as that of high-frequency oscillation at siniiUu- lung volumes in
this model of lung injury

Preliniinarj Results on Nursing Workload in a Dedicated Weaning
Center — Vitacca M, Clini E, Porta R. .Xmbrosino N. Intensive Care Med
2000 Jun;26(6):796-799.

OBJECTIVE; To evaluate the nursing time required for difficult-to-wean
patients in a dedicated weaning center (WCl and to examine the cone-
lalion of the nursing time with nursing w<irkload (NW) scores and with

450

Respiraior^ Carh • May 2001 Vol 46 No 5

Abstracts

clinli.';il ->i.'vcri(y and dcpoiidcncy. SETTING: liuii hcd V\ C ol .1 piilino'
nary rchahililalion dcparlniciil. INTURVliN 1 ION: None. DKSKJN ANn
MEASLIRIiMliN T: Prospcclivc. i)bsoi\alii)nal sludy ol 46 conseculivi;
palionls admitted Id a ionji-terni \VC. Time required hy items of the Time
Oriented Senre System (TOSS) and Diher tasks specific to rcspiratoiy
inlcniiediate intensive care units wci£ evaluated tor all the uclivitics
performed on each patient in the first 2 days after admission. Patient
dependency and level of nursing care at admission were measured using
the Dependence Nursing Scale iDNSi and the Intermediate Therapeutic
lnter\enlion Score System iTISS-inll. The Acute Physiology and Chronic
Health Evaluation l.\P.\( Hij II score was also recorded at admission.
RliSLiLTS: On the llrM day each patient needed 45 S 15% (6.1 ± l^/i .
45 * 22**. and 29 i Ur-t lor the three nursing shifts) of allocated single
nursing time. On the TOSS on the first day patients required a daily mean
28 ± 10% of total available nursing lime: on the second day the results
did not change. Tiine of care in the first 24 h was only weakly related to
DNS. APACHE II score, and TlSS-int: only DNS was able (although
weakly; r = 0.45) to predict minutes of nursing care. CONCLUSIONS:
In difficult-to-wean patients from mechanical ventilation the nursing lime
in the first 2 days after admission is high. The use of TOSS may under-
estimate NW by about 3S'f. Although only DNS showed the ability lo
predict minutes of care, the weak relationship limits its \aluc in clinical
practice.

Midazolam and 1% Propofol in Long- lerm Sedation of Iraunui-
tizcd Critically III l'alient.s: KfTieacy and Safety Comparison — San-
diumenge Camps A. Sanchc/-l/quierdo Riera JA. Toral Vazquez D. Sa
Borges M. Pcinado Rodriguez J, Alted Lopez E. Crit Care Med 2000
Nov;28( 1 11:3612-3619.

OBJECTIVE: We proposed to coinpare the efficacy and safety of mida-
zolam and propofol in ils new preparation (2'f propofol) when used for

prolonged, deep sedation in Iraumalizcd. crilicully ill patients. We also
relrospeclively compared 2'ii propofol with its original preparation. 1%
propolol. used in a previous study in a similar and contemporary set of
patients. DESIGN: A prospective. randomiz.ed. unblinded trial (midazo-
lam and 2*"/} propofol) and a retrospective, contemporary trial (2'/< propo-
fol and \'7c propofol). SETTINGS: A trauma intensive care unit in a
tertiary university hospital. PATIENTS: A total of 63 consecutive trauma
palienls. admitted within a period of 5 months and requiring mechanical
\enlilatory support for >4X hrs. 43 of whom (73'i I suffered severe head
trauma. We also retrospectively compared the I'm propolol group with a
scries of palienls in whom \'7c propolol was used. INTERVENTIONS:
For the prospective trial, we randomized two groups — a midazolam group
with continuous adniinisiralion of midazolam at dosages 0.1-0.35 mg/
kg/hr. and a I'.i propofol group «ilh continuous infusion at dosages 1.5-6
mg/kg/hr Equal dosages of analgesics «ere administered. Similar man-
agement protocols were applied in the I'i propofol group, used in the
retrospective analysis with 2'< propofol. MEASLREMENTS AND MAIN
RESULTS: Epidemiologic and efficacy variables were recorded. Hemo-
dynamic and biochemical variables were also monitored on a regular
basis. Neuromoniloring was also performed on those patients with head
trauma. Sedation adequacy was similar and patient behavior after drug
discontinuation s^as not different in either prospective group (midazolam
and I'l propolol). Hemodynamic or neuromonitoring variables were also
similar for both groups. Triglyceride levels were significantly higher in
the 2'/< propofol group compared with the midazolam group. A higher
number of therapeutic failures because of sedative inelficacy was seen in
the I'/r propofol group compared with the midazolam group, especially
during the first sedation days. When comparing 2'^; propofol and 1%
propofol. a significantly higher number of therapeutic failures because of
hypertriglyceridemia were found in the \'i propofol group, as opposed lo
a major number of therapeutic failures because of inelficacy. found in the

Summer Forum

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Respiratory Cari; • Ma> 2001 Voi 46 No 5

Abstracts

Z'/r propolol group. CONCl.l'SIONS; Pidpoliils new pivp;ii;ilion is sale
when used in severely traumali/ed palienls. lis more eiineentraled liir-
mula improves the lipiil overload problem seen u ith the prolonged use ot
the previous preparation. Nevertheless, a major number ot therapeutic
failures were detected vsith 2% propolol because of the need for dosage
increase. This fact could be caused by a different disposition and tissue
distribution pattern of both propofol preparations. New studies w ill be
needed to confirm these results

Kfl'iTliveness of Knd-lidal Carbon Dioxide Tension for .M(>ni((irin)>
Thromholytic Therapy in .\cule I'lilmnnary Kinbolism — Wicgand I'K,
Kurowski V. Giannitsis E, Katus H,-\, Djonlagic H. Cril Care Med 2(100
Nov;28( 1 1 1:.1588-.^592.

OBJECTIVE: In acute massive pulmonary embolism uiih hemodynamic
instability, nionitoriiig of pulmonary artery pressure can be used to assess
the efficacy of thrombolytic therapy. As a noninvasive alternative to
pulmonary artery catheterization, we investigated the efficacy of contin-
uous monitoring of end-tidal CO, tension. DESIGN: In 12 patients with
massive pulmonary embolism who required mechanical ventilation, mean
pulmonary arterial pressure (MPAP) and cnd-lidal carbon dioxide tension
(ET(.,,J were registered continuously during thrombolytic therapy. P.,, ,),.
cardiac index as estimated by thermodilution catheter and respiratory
ratio of arterial oxygen tension and inhaled oxygen concentration (P.,o,/
F|o,l were determined every 60 mins. MEASUREMENTS AND MAIN
RESULTS: Before thrombolysis, MPAP (.M.5±9.8 mm Hg) and the
difference between P;,co. •""' ET^o, (10. 1 ±4.7 mm Hg) were markedly
increased compared with normal values. Continuously monitored MPAP
was related to ETco, for both all patients (r* = 0.42; p < 0.001 1 and
individually (mean r-' = 0.92: range. 0.79-0.98; p < 0.001). In ten sur-
vivors, the mean cardiac index and P;,(,,/F,o, increased during therapy
from I.7i0.4 to 2.8±0.6 L/min X nr and I2.'i±27 to 28S±50 mm Hg
(p < 0.01. respectively). In these patients, the difference between P,,co.
and ETc„, decreased from 9.8±4..'S to 2.8±0.9 mm Hg (p < 0.001)!
Recurrent embolism was detected in two patients by sudden reduction of
ETco,- CONCLUSIONS: Analysis of ET^o, allows monitoring of the
efficacy of thrombolysis and may reflect recurrent embolism. Thus, on
the basis of this small study, analysis of ET^-o, appears to be useful for
noninvasive monitoring in mechanically ventilated patients with massive
pulmonary embolism.

lory arrest is lifesaving and should continue to be taught and emphasized
in basic life support courses.

I'lrciitancous IracheDsloniy in Critically III Patients: .\ Prospective,
Kandoniized Compari.son of I wo Techniques — Nales NL. Cooper DJ.
Myles PS. Scheinkestel CD. I uxen DV. Crit Care Med 2000 Nov:28( 1 1 ):
.•17.14-37.19.

OB.IECTIVF.: To prospectively compare two commonly used methods
lor percutaneous dilalional tracheostomy (PDT) in critically ill patients.
DESKiN: Prospective, randomized, clinical trial. SETTING: Trauma and
general intensive care units of a university tertiary teaching hospital,
which is also a level I trauma center. PATIENTS: One hundred critically
ill patients with an indication for PDT. INTERVENTIONS; PDT with
the Ciaglia technique using the Ciaglia PDT introducer set and the Griggs
technique using a Griggs PDT kit and guidewire dilating forceps. MEA-
SUREMENTS AND MAIN RESULTS: Surgical time, difficulties, and
surgical and anesthesia complications were measured at 0-2 hrs. 24 hrs.
and 7 days postprocedure. Groups were well matched, and there were no
differences between the two methods in surgical time or in anesthesia
complications. Major bleeding complications were 4.4 times more fre-
quent with the Griggs PDT kit. With the Ciaglia PDT kit. both intraop-
erative and at 2 and 24 hrs. surgical complications were less common
(p = 0.023) and the procedure was more often completed without expert
assistance (p = 0.013). Tracheostomy bleeding was not associated with
either anticoagulant therapy or an abnormal clotting profile. Multivariate
analysis identified the predictors of PDT complications as the Griggs
PDT kit (p = 0.027) and the Acute Physiology and Chronic Health
Evaluation (APACHE) II score (p = 0.041 1. The significant predictors of
time required to complete PDT were the APACHE II score (p = 0.041).
a less experienced operator (p = 0.0001). and a female patient (p =
0.013). CONCLUSIONS: Patients experiencing PDT with the Ciaglia
PDT kit had a lower surgical complication rate {2% vs. 259?-). less op-
erative and postoperative bleeding, and less overall technical difficulties
than did patients undergoing PDT with the Griggs PDT kit. Ciaglia PDT
is. therefore, the preferred technique for percutaneous tracheostomy in
critically ill patients.

Comparison of the Response of .Saline Tonometry and an .Automated
Gas Tonometry Device to a Change in CO, — Noone RB. Bolden JE,
Mvthen MG. Vaslef SN. Crit Care Med 2(X)0 Nov;28( 1 1 ):3728-3733.

Effects of Inspired (Jas Content During Respiratory Arrest and Car-
diopulmonary Resuscitation — Idris AH. Crit Care Med 2000 Nov;28( 1 1
Suppll:Niy6-N|y8.

Mouth-to-mouth and hag-valve-mask ventilation have been an indispens-
able part of cardiopulmonary resuscitation (CPR). However, only re-
cently have the effects of dillerent tidal volumes on arterial oxygenation
been reported for mouth-lo-mouth atid bag-valve-mask ventilation. Cur-
rently recommended tidal volumes (10-15 mL/kg) are associated with an
increased risk of gastric inflation because they produce high peak in-
spiratory pressures. An animal model of ventilation with an unprotected
airway showed that a smaller tidal volume (6 mL/kg) is as effective as a
larger tidal volume ( 12 mL/kg) in maintaining S,,„, at >96?{-. However,
a smaller tidal \olume with exhaled gas \entilation produced a mean S ,,,, of
48%. which Is ineffective. Ventilation gas mixtures have been studied in
models of cardiac arrest and CPR. One study showed that ventilation
with air during 6 mins of CPR resulted in a return of spontaneous cir-
culation in 10 of 12 animals compared with only 5 of 12 animals ven-
tilated with exhaled gas (p<0.04). Arterial and mixed-venous P,,, were
significantly higher, and P(.„, was significantly lower in the air ventila-
tion group. Investigations of the cardiovascuUir effects of mouth-to-mouth
ventilation during CPR suggest that there are adverse effects during low
blood fiow slates. However, mouth-to-mouth ventilation during respira-

OBJECTIVE: To examine the speed of response of saline tonometry and
an automated gas tonometry system by using standard tonometry cathe-
ters. DESIGN: In vitro validation study. SETTING: Experimental re-
search laboratory. INTERVENTIONS: Tonometry catheters were placed
in a test chamber designed to simulate the lumen of a hollow viscus and
were exposed to a rapid change in CO. from OVc to 5'7c or lO'^f . Measured
CO, over time v\as fit to a mathematical model to determine the response
time constant (the time to reach 63'1 of the final value) for each system.
MEASliREMENTS AND MAIN RESULTS: Response time to a change
in COj was significantly faster with the automated gas system than with
traditional saline tonometry. The mathematical time constant for a 5%
change in CO, in a gas en\ironment was 2.8 mins (9.S9r confidence
interval. 2.6-3.0 minsi for the gas and 6.3 mins (95% confidence interval.
5.8-7.3 mins) lor the saline technique. These times were longer for the
CO, change in a liquid environment: The time constant was 4.6 mins
{959c confidence interval. 4.5-4.7 mins) for the gas system and 7.8 mins
(95% confidence interval. 7. 15-8.6 mins) for the saline tonometry. There
was a significantly lower final equilibration value for the CO, measure-
ment with saline tonometry. There was essentially no difference in time
constants for each system for a 5% change compared with a 10% CO,
change, except for a slightly faster time constant for the gas tonometry
system with a 5% change in the gas environment (5%: 2.8 mins vs. 10%:
3.3 mins) CONCLUSIONS: The automated gas tonometry system has a

452

RESPiRAi()R> Care • Ma^ 2001 Voi 46 No 5

AUSIK.UIS

Mgiiificaiilly liisicr rcsponsi- In j chanjic in CO, lliaii coincnliorKil salmc
lonnmctni

Inhuk'd Nitric Ovidc Ri'duiTs Ihe Need for lAlraiiirpDrrii! Mi'iii-
hraiif Owmiialiiin in Inlanls Hilh IVrsisliiil I'lilmonarv ll>|HTl»n-
sion of the NcHhorn Chn^lou H. Van Marlcr U . Wcssci Ul.. Allrcd
liN. KaiK- JW. riionipMin Jt. ct al. Crit Care Med 2(XK) Nov;28(ll):
?722-3727.

OBJECTIVE: We previously reponed improved oxygenation, but no
change, in rates of extracorporeal membrane oxygenation (ECMOl use or
death among infants with persistent pulmonary hypertension of the new-
bom who received inhaled nitric oxide (NO) with conventional ventila-
tion, irrespective of lung disease. The goal of our study was to deteniiine
whether trealment with nihaled NO improves oxygenation and clinical
outcomes in infants with persistent pulmonary hypertension of the new-
born and associated lung disease who are ventilated with high-frequency
oscillatory ventilation (HFOV I. DE.SIGN: Single-center, prospective, ran-
domized, controlled trial. SETTING: NewlHim intensive care unit of a
tertiary care teaching hospital. PATIENTS: We studied infants with a
gestational age of ^.^4 wks who were receiving mechanical ventilatory
support and had echocardiographic and clinical c\ idence of pulmonary
hypertension and hypoxemia (P,,,, filOO mm Hg on F,o, = 1.0), despite
optimal medical management Infants with congenital heart disease, dia-
phragmatic hernia, or other major anomalies were excluded. INTER-
VENTIONS: The treatmenl group received inhaled NO. whereas the
control group did not. Adjunct therapies and ECMO criteria were Ihe
same in the two groups of patients. Investigators and clinicians were not
masked as to treatment assignment, and no crossover of patients was
permitted. MEASUREMENTS AND MAIN RESULTS: Primary out-
come variables were mortality and use of ECMO. Secondary outcomes
included change in oxygenation and duration of mechanical ventilatory
support and supplemental oxygen therapy. Forty-two patients were en-
rolled. Ba.seline oxygenation and clinical characteristics were similar in
the two groups of patients. Infants in the inhaled NO group (n = 21 ) had
improved measures of oxygenation at 15 mins and I hr after enrollnicnl
compared with infants in the control group (n = 20). Fewer infants in the
inhaled NO group compared with the control group were treated with
ECMO (I4<i vs. 55%. respectively; p = 0.001). Mortality did not differ
with treatment assignment. CONCLUSIONS: Among infants ventilated
by HFOV. those receiving inhaled NO had a reduced need for ECMO.
We speculate that HFOV enhances the effectiveness of inhaled NO treal-
ment in infants with persistent pulmonary hypertension of the newborn
and a.ssociated lung disease.

Improved Outconu's of Children with Malijjnancy .Admitted to a
Pediatric Intensive Care Unit— Hallahan .\k. Shaw PJ. Row ell G.
OXonnell A, Schell D. Gillis J. Crit Care Med 2000 Nov;28(l 1):37I8-
372I.

OBJECTIVE: To assess the acute and long-term outcomes of children
admitted to the intensive care unit with cancer or complications after
bone marrow transplantation. DESIGN: Retrospective analysis of data-
bases from a prospective pediatric intensive care unit (PICU) database
supplemented by case notes review. SETTING: .\ PICU in a tertiary
pediatric hospital. PATIENTS: All children with malignancy admitted to
the PICU between May I. 1987. and April .30. 1996. INTERVENTIONS:
None. MEASUREMENTS AND MAIN RESULTS: There were 206
admissions to the PICU during a 9-yr study period of 150 children with
malignancies or complications after bone marrow transplantation. Forty
patents died in the PICU (27<7( mortality rate). The most frequent indi-
cations for PICU admission were shock and respiratory disease. Of 56
children admitted with shock, there were 16 deaths (29'r mortality rale).
In 24 episodes of sepsis, inotropic and ventilatory support were required
and 13 patients (54%) survived. Analysis of long-term survival gave

estiinales of 50% survival for all oncology patients admitted to the PICU
and 42% for those admitted for shock. CONCLUSIONS: A high pro-
portion of oncology patients admitted to the PICU requiring intensive
intervention survive and go on to be cured of their malignancy. Our study
suggests the PICU outcome for these patients has improved.

.\n lllipri)M(l In \ iMi Kat Model for the Slud\ of Mechanical \ in-
tilalory Support Kffetls on Organs Distal to the LunR Valen/a F.
Sibilla S. I'orro G A. Hianibilla A. 1 rcdici S. .Nicnhni G. et al, Crit Care
Med 2(KX) Nov;28( 1 1 ):3697-3704.

OBJECTIVE: To study the influence of different mechanical ventilatory
support strategies on organs distal to the lung, we developed an in vivo
rat model, in which the effects of different tidal volume values can be
studied while maintaining other indexes. DESIGN: Prospective, random-
ized animal laboratory investigation. SETTING: University laboratory of
Ospedale Maggiore di Milano-lnslituto di Ricovero e Cura a Carattcre
Scientillco. SUBJECTS: .Anesthetized, paralyzed, and mechanically ven-
tilated male Sprague-Dawley rats. INTERVENTIONS: Two groups of
seven rats each were randomized to receive tidal volumes of either 25%
or 75% of inspiratory capacity (IC). calculated from a preliminary esti-
mation of total lung capacity. Ventilation strategies for the two groups
were as follows: a) 25% IC. 9.9±0.8 mL/kg: frequency. 59±4 bcals/min:
positive end-expiratory pressure. 3.6±0.8 cm H,0: and peak inspiratory
airuay pressure (P,„). 13.2 ±2 cm H,0: and b) 75% IC. 29.8 ±2.9: fre-
quency. 23i:13: positive end-expiratory pressure. 0: peak inspiratory
P,„. 29.0±3. MEASUREMENTS AND MAIN RESULTS: Mean arte-
rial pressure (invasively monitored! remained well above adequate per-
fusion pressure \ alues throughout, and no significant difference was seen
between the two groups. P^,,,. pHa. and P., ,,, values were compared after
60 mins of ventilation and again, no significant difference was seen
between the two groups (P^o,. 269 ±25 and 260 ±55 ton-; pHa. 7.432 ±0.09
and 7.415±0.03; P^co,- 35!4±8 and 32.5±2 ton-, for the 25% IC and
75% IC groups, respectively). Mean P^^s were not different (6.4±0.8 cm
H,0 in the 25% IC groups, and 6.1 = 1.2 in the 75% IC groups, respec-
tively). At the end of the experiment, animals were killed and the liver
and kidney isolated, fixed in 4% fonnalin. cut. and stained for optic
microscopy. Kidneys from rats ventilated with 75% IC showed increased
Bowman's space with collapse of the glomerular capillaries. This oc-
curred in a greater percentage of rats ventilated with 75% IC (0.67 ±0.2
vs. 0.29 ±0.2. 75% IC vs. 25% IC. respectively: p < 0.05). Periva.scular
edema was also present in rats ventilated with 75% IC (p < 0.05).
Morphomelric determinations of the empty zones (index of edema) dem-
onstrated a trend toward differences between 75% IC livers and 25% IC
(I) 14-0.05 vs. 0.1 1 ±0.02. respectively). CONCLUSION: We conclude
that it is possible to study the effects of mechanical ventilatory support on
organs distal lo the lung by means of an in \i\o ral model.

The C"omfort of IJreathin};: \ Study with \ olunteers .\.s,se.ssin(; the
Intluence of \ arious Modes of .Assisted Ventilation— Russell WC.

Grccr JR. Crit Care Med 2(K)0 Nov:28( 1 1 1:3645-3648.

OBJECTIVE: To assess the subjective feeling of comfort of healthy
volunteers breathing on various modes of ventilation used in intensive
care. DESIGN: A randomized, prospective, double-blinded, crossover
inal using volunteers, SETTING: An intensi\e care unit (ICU) in a
teaching hospital. INTERVENTIONS; Wc compared, by using healthy
volunteers, the subjective feeling of comfort of three modes of ventilation
used during the weaning phase of critical illness. We used healthy vol-
unteers to avoid other distracting influences of intensive care that may
conlound Ihe primary feeling of comfort. The modes we compared were
synchronized intermittent mandatory ventilation, assisted spontaneous
breathing, and biphasic positive airway pressure. The imposed ventilation
was comparable with 50% of the \ olunteers' noniial respiratory effort.
The volunteers breathed via a mouthpiece through a ventilator circuit.

Respiratory Care • May 2001 Vol 46 No 5

453

program

Taking the Mystery
Out of Weaning the
Pediatric Patient
from the Ventilator

Peter Betit, BS, RRX FAARC.
and Richard D Branson,
BA. RRT, FAARC

Learn when to begin the process
and how to recognize critical
events in weaning a pediatric
patient. Also teaches the physio-
logical differences between the
adult and pediatric patient and
why weaning of the pediatric
patient is different The presenta-
tion confronts participants with
options in providing assisted ven-
tilation and the correct seleaion
of options that expedite weaning.

Videotape available

program

Pulmonary
Rehabilitation:" ^^
Standard Care
for Chronic Lung
Disease Patients

Trina Limberg, BS, RRT,
and Thomas J. Kallstrom,
RRT FAARC

Presentation details when to refer
a patient for pulmonary rehabili-
tation and the four elements nec-
essary for the successful opera-
tion of a rehabilitation service
Details hov/ to prepare a treat-
ment plan during assessment
and how to modify it based on
subsequent evaluations as well as
how to incorporate rehabilitation
techniques into routine bedside
therapy sessions.

Videotape available

program

Noninvasive
Ventilation: Thi
Latest Word

Dean R. Hess, PhD, RRT,
FAARC, and Richard D.
Branson, BA. RRT FAARC

Learn how to avoid intubation in
the acutely ill patient through
identification of patients most
lil<ely to benefit from noninvasive
ventilation. Learn selection and
proper fit of full masl« or nasal
masks and how to select the
proper ventilator based on the
patient's condition and desired
outcomes. Also learn when to
malce adjustments to achieve the
goals of unloading respiratory
muscles and achieving good
patient/ventilator synchrony

Uve Videoconference ■

April 24, 1 1:30 a.m. - 1.00 p.m.

Central Time

Teleconfurence with VicJeou^pt

May 29, 1 1 .-30 a.m. - 1 2:00 Noon

Central Time

program

Education of th
Patient with Asthma'

Tracey Mitchell, RRT RPFT and
Thomas J. Kallstrom, RRT
FAARC

This program teaches how to
ensure that patients understand
the disease process of asthma
and their care plan for effective
disease management And, it
details what patient education
materials are available, their con-
tent, where to find them, and the
best methods of presentation,
including new terminologies,
analogies, and techniques.

Sponsored in part by an educaDonal
grant from Sepracor, Inc,

bve Videoconference -

May 22, 1 1 30 am I 00 p m

Central Time

Teleconference With Vi()' ■ >,

June 19, 1 1 :30 a.m. - 1 2:00 Noon

Central Time

ARDS: The Disease
and Its Management

Leonard D. Hudson, MD,
and David J. Pierson, (VID,
FAARC

Presents the four diagnostic crite-
ria for ARDS and the six clinical
risl< factors that place patients at
increased lilcelihood for develop-
ing ARDS. The program will
teach viewers how to under-
stand the implications of the
lower and upper inflection
points on the pressure-volume
curve of the respiratory system in
ARDS patients, and instruct them
in the calculation of estimated
required tidal volume

Uve Videoconference

June 26, 1 1 :30 a.m. - 1 :00 p.m.

Central Time

Teleconference with Videotape -
July 17, II :30 a.m. - 1 2:00 Noon
Central Time

program

i"^

New Respiratory Drugs.
What, When, and How?

Joseph L Rau, PhD, RRT
FAARC, and Patrick J. Dunne,
IWEd, RRT, FAARC

Introduces participants to new
formulations such as racemic
drug mixtures and single isomers
and their effective duration and
how they lead to lower costs
with improved patient responses.
Viewers will learn the use of
improved anticholinergics in the
treatment of asthma patients and
learn the uses and effects of
inhaled anti-Infective agents.

Sponsored in part by an educational
grant from Sepracor, Inc.

bve Videoconference

Aug. 14, I 1 :30 a m - 1 :00 p,m.

Central Time

■ irerence with Videotape -
Sept 11. 11:30 a.m.- 12:00
Noon Central Trme

Invasive Ventilatior
The Latest Word

Richard Kallet, fWS, RRT and
Richard D Branson, BA, RRT
FAARC

Learn how proper ventilator
management can preclude
inflicting harm on the patient
and why it is essential for the
clinician to understand the func-
tion and mechanics of newer
mechanical ventilators. Also
learn how reducing the patient's
work of breathing is essential in
reducing the additional load on
ventilatory musculature, and
why reinflating lungs and
enhancing the functional area
of the lung demands extraordi-
nary means.

Live Videoconference -

Sept. 25, 1 1 :30 a.m. - 1 :00 p.m.

Central Time

Tei^^conference with Videotape -
Oct, 16, 11:30 a.m. - 12:00
Noon Central Time

program

Test Your Lungs,
Know Your Number,
Prevent Emphysema

Thomas L. Petty, MD, FAARC
and David J, Pierson, MD,
FAARC

Reviews the classic signs of
COPD with an emphasis on
emphysema and a discussion on
the measures used to relieve
symptoms and slow disease pra
gression. Covers the importance
of pulmonary function tests to
determine VC, FFC, and FEVi,
and why getting patients to
know their numbers is the key
to early diagnosis and successful
treatment

I (x'e Videoconferenre -

Oct, 23. 1 1 :30 am, - 1 :00 p.m.

Central Time

Teleconference with Videotape -

Nov. 20, 11:30 a.m.- 12:00

Noon Central Time

Complete Educational Programs
in the Convenience of Your Facility

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only, without live question and answer session, does not earn continuing education credit.

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Abstracts

and ihc modes of vonlilation were introduced in a randomized manner.
MEASUREMENTS AND MAIN RESULTS; We measured visual ana-
log scores for comfort for the three modes of ventilation and collected a
ranking order and open-ended comments. We demonstrated that at the
level of support we imposed, assisted spontaneous breathing was the
most comfortable mode of ventilation and that synchronized intermittent
mandatory ventilation was the most uncomrorlable. These results were
strongly supported by both the ranking scale and comments of the vol-
unteers. CONCLUSIONS: .Assisted spontaneous breathing was the most
comfortable mode of ventilation because the pattern was primarily de-
termined by the volunteer. Synchronized intermittent mandatory venti-
lation was the most uncomfortable because the ventilatory pattern was
imposed on the volunteers, leading to ventilator-volunteer dyssynchrony.
We also conclude there is wide individual variation in the subjective
feeling of comfort. Whereas the mode of ventilation in ICUs is based
primarily on the physiologic needs of the patient, the feeling of comfort
may be considered when choosing an appropriate mode of ventilation
during the weaning phase of critical illness.

Kstlmatinn Cardiac Filling l*re.s,sure in Mechanically \ entilated Patients
with Hypcrinnation— Teboul JL. Pinsky MR. Mercat A, Anguel N. Ber-
naidin Ci. Achard JM. et al. Crit Care Med 2aX) Nov:28(l l):3631-3636.

OBJECTIVE: When positive end-expiratory pressure (PEEP) is applied,
the intracavitary left ventricular end-diastolic pressure (LVEDP) exceeds
the LV filling pressure because pericardial pressure exceeds at end-
expiration. Under those conditions, the LV filling pressure is itself better
rellected by the transmural LVEDP (tLVEDP) (LVEDP minus pericar-
dial pressure). By extension, end-expiratory pulmonary artery occlusion
pressure (eePAOP), as an estimate of end-expiratory LVEDP, overesti-
mates LV filling pressure when pericardial pressure is >0, because it
occurs when PEEP is present. We hypothesized that LV filling pressure
could be measured from eePAOP by also knowing the proportional trans-
mission of alveolar pressure to pulmonary vessels calculated as index ot
transmission = (end-inspiratory PAOP-eePAOP)/(plateau pressure-to-
tal PEEP). We calculated transmural pulmonary artery occlusion pressure
(tPAOP) with this equation; tPAOP = eeP.AOP-l index of transmission X
total PEEP). We compared tPAOP w ith airw ay disconnection nadir PAOP
measured during rapid airway disconnection in subjects undergoing PEEP
with and without evidence of dynamic pulmonary hyperinflation. DE-
SIGN; Prospective study. SETTING: Medical intensive care unit of a
university hospital. PATIENTS; We studied 107 patients mechanically
ventilated with PEEP for acute respiratory failure. Patients without dy-
namic pulmonary hyperinflation (group A: n = 5Sl were analyzed sep-
arately from patients with dynamic pulmonary hyperinllation (group B;
n = 49). INTERVENTION; Transieiit airway disconnection. MEASURE-
MENTS AND MAIN RESULTS: In group A. tPAOP (8.5±6.0 mm Hg)
and nadir PAOP (8.6±6.0 mm Hg) did not differ from each other but
were lower than eePAOP (12.4±5. 6 mm Hg: p < C.G."!). The agreement
between tPAOP and nadir PAOP was good (bias, 0.15 mm Hg; limits of
agreement. -1.5-1.8 mm Hg). In group B. tPAOP (9.7±5.4 mm Hg) was
lower than both nadir PAOP and eePAOP ( 12 1 i5.4 and 13.9±5.2 mm
Hg. respectively; p < 0.05 for both comparisons). The agreement be-
tween tPAOP and nadir P.AOP was poor (bias. 2.3 mm Hg; limits of
agreement, -0.2-4.8 mm Hg). CONCLUSIONS: Indexing the transmis-
sion of proportional alveolar pressure to PAOP in the estimation of LV
filling pressure is equivalent to the nadir method in patients without
dynamic pulmonary hyperinflation and may be more reliable than the
nadir PAOP method in patients with dynamic pulmonary hyperinflation.

OBJECTIVE; To examine the relationship between the use of sedative
and neuromuscular blocking agents dunng a patient's intensive care unit
(ICU) stay and subsequent measures of health-related quality of life.
DESIGN; Cross-sectional mail survey and retrospective medical record
abstraction of a prospectively identified cohon of lung injury patients.
SETTING; ICUs in three teaching hospitals in a major metropolitan area.
PATIENTS: Patients with acute lung injury (n = 24). INTERVEN-
TIONS: None- observational study. MEASUREMENTS AND MAIN
RESL'LTS: Patients' charts were reviewed for those patients returning
postdischarge quality-ol-life questionnaires. Duration, daily dose, and
route of administration for sedatives and neuromuscular blocking agents
were abstracted from ICU flow sheets. Relationships among ICU vari-
ables (days of sedation, days of neuromuscular blockade, and severity of
illness as measured by Acute Physiology and Chronic Health Evaluation
111 score) and outcomes (symptoms of depression and symptoms of post-
traumatic stress disorder) were assessed. Depressive symptoms at fol-
low-up were correlated with days of sedation (p = 0.007), but not with
days of neuromuscular blockade or initial severity of illness. The com-
posite posttraumatic stress disorder symptom impact score was correlated
with days of sedation (p = 0.006) and days of neuromuscular blockade
(p = 0.035), but not with initial severity of illness. There were no sig-
nificant differences between the frequency of patients reporting a specific
posttraumatic stress disorder symptom in the high sedation group and the
low sedation group, and there were no significant differences in specific
posttraumatic stress disorder symptoms between the group that had re-
ceived neuromuscular blockade and those who had not. CONCLUSIONS:
The use of sedatives and neuromuscular blocking agents in the ICU is
positively associated with subsequent measures of depression and post-
traumatic stress disorder symptoms 6-4 1 months after ICU treatment for
acute lung injury.

Longitudinal .Study of Pediatric House Officers' Attitudes Toward
Death and Dying— Vazirani RM, Slavin SJ, Feldinan JD. Crit Care Med

2000 Nov;28(ll):3740-3745.

OBJECTIVE: To investigate pediatric residents' attitudes toward end-
of-life issues and their education in dealing with these issues. DESIGN;
Exploratory survey. SETTING: Department of Pediatrics at the Univer-
sity of California. Los Angeles, Center for Health Sciences. SUBJECTS;
Volunteer sample. A total of 182 of 203 pediatric residents at all levels
of training ctimpleted anonymous questionnaires. INTERVENTIONS;
None. MEASUREMENTS AND MAIN RESULTS; Data on residents'
attitudes toward issues of death and dying and the efficacy of educational
inter\entions were collected over a 4-yr period. When entering training,
house officers are uncomfonable dealing with death and dying issues
(mean. 3.3 of 5; 5 = not comfortable). By the end of their training, these
house officers become comfortable dealing with these issues (mean, 2.2;
p < 0.05). During their first 2 yrs of training, house officers report that
their medical education is not helping them to deal with the issues of
death and dying (mean, 3.3). At the end of their third year of training,
residents report that their education is helping them to deal with these
issues (mean, 2.3; p < 0.05). Strikingly, as house officers progress through
their residency, they become less comfortable with the idea of adminis-
tering pain medication to a dying patient, because the pain medication
might hasten the patient's death ip < 0.05). CONCLUSIONS: Pediatric
residents may benefit from more formal training in the practical aspects
of death and dying issues. Residency education should do more to ad-
dress these issues systematically for the benefit of both the residents and
the patients and family members.

Intensi\e Care L nit Drug Use and Subsequent Quality of life in
Acute Lung Injury PatlenLs — Nelson BJ, Weincit CR, Bury CL.
Marinelli W A. Gross CR. Crit Care Med 2(XX) Nov;28( 1 1 );3626-3630.

Role of Mmilh-to-\Iouth Rescue Breathing In Bystander Cardiopul-
monary Resuscitation for .\sphyxlal Cardiac .\rrest — Berg R.A. Crit

Cue Med ;000 Nov;2Sill Suppl):Niy3-Niy5.

456

Respiratory Care • MA^ 2001 Vol 46 No 5

Abstracts

There is increasing evidence ih.ii m.uiili lo iiuuiili rescue breathing may
not be necessar) during hriel periods nl b_\ slander cardiopulmonary re-
suscilalion (CPR) lor \enlricular fibrillalion. In conlrasi u> venlricular
I'lbrillalion cardiac arresls. il has been assumed Ihal rescue brealhing Is
essenlial lor irealmenl ol asphyxial cardiac arresls because Ihe cardiac
arrests rvsull from inadec|uale ventilation. This review explores the role
of niouth-to-mouth rescue breathing during bystander CPR lor asphyxial
cardiac amrsts. Clinical data suggest that survival from apparent asphyx-
ial cardiac arrest can iKcur alter CPR consisting of chest compressions
alone, without rescue breathing. Two randomized, controlled swine in-
vestigations using models ol bystander CPR lor asphyxial cardiac arrest
establish the lollowing: a I that pronipl milialion of bystander CPR is a
crucially important intervention; and bt that chest compressions plus
mouth-io-moulh rescue breathing is markedly superior to cither tech-
nique alone. One of these studies further demonstrates that early in the
asphyxial pulseless arrest process doing something (mouth-to-moulh res-
cue breathing or chest compressions) is better than doing nothing.

Cardiopulniiinarv Resuscilatidii «ithi)iit \ c'iitilalii>n — kcrii klV (ril
Care Med 2000 Nov;2S(l I Suppl);NIS(i-.M!Sy.

Current resuscitation methods, although occasionally effective, rarely
perform as well as initially anticipated. Some of the disappointment can
be attributed to the difficulty of the task for many, including both pro-
fessional and lay first responders. Significant attention has been paiil
recently to the need to simplify both the technique and the teaching of
resuscitation. In considering simplification of the current resuscitation
scheme, a logical start is an honest reappraisal of the importance and
priorities of each of the once sacrosanct .ABCs. specifically, establish-
ment of an Airway, anificial Breathing (moulh-lo-moulh breathing), and
chest compressions for temporary Circulation. Experimental data con-
tinue to accumulate indicating that most important within this triad is
circulation. Adequate oxygen exists within the blood during at least the
first 10 mins of cardiac arrest. If circulation is provided to distribute such
oxygen, no survival disadvantage results with chest compression-only
basic life support (BLS) efforts. Even a totally occluded airway during
the first 6 mins of cardiac arrest does not compromise survival if rea-
sonable circulation is provided with chest compressions. Clinical studies
support the same conclusion that what most influences survival in any
BLS effort is circulation, not ventilation. Belgium investigators have
shown equal survival rates among those treated with chest compressions
plus ventilation and those who received chest compressions alone. Tele-
phone dispatcher-guided BLS cardiopulmonary resuscitation (CPR) has
likewise shown no surv ival disadvantage to chest compression-only CPR
when compared with telephone-guided standard BLS CPR. Based on this
reasoning, a new simplified BLS method has been proposed. "Staged"
CPR consists of a strategy to initially teach laypersons a simplified
approach to BLS. which requires only chest compressions and not moulh
to-mouth breathing. "Bronze" CPR. in which chest compression-only
BLS is taught, was compared with the standard European Resuscitation
Council BLS course for laypersons. Manikin "exit testing" at course
completion has revealed significant advantages of the simplified ap-
proach compared with standard CPR courses for the lay public.

Improving the EITicienc) of Cardiopulmonary Kesuscitutiun v\ith an
Inspiralorv Impedance I'hreshold Naive — Lurie K. Zielinski I. McK
mte S. Sukhuiii P Cm Cue .Med ;(1()() Nov;28(ll Suppl):N207-N20y.

In an effort to improve the efficiencv of cardiopulmonary resuscitation
(CPR). a new inspiratory impedance threshold valve has been developed
to enhance the return of blood to the thorax during the chest decompres-
sion phase. This new device enhances negative intrathoracic pressure
during chest wall recoil or the decompression phase, leading to improved
vital organ perfusion during both standard CPR and active compression-
decompression CPR Wiih active compression-decompression CPR. ad-

dition of Ihe impedance threshold valve results in sustained dia.slollc
pressures of >.S5 mm Hg in patients in cardiac arrest. The new valve
shows promise for palienis in asystole or shock relractory ventricular
fibrillation, when enhanced return of blood flow to the chest is needed to
"prime the pump. ' Ihe potential long-term benefits of this new valve
remain under study.

Spontaneous liemopneuniolhiirux in W iiintn Kiser AC. Roberts CS.

South Med J 21100 Dcc.'J.li 12).I2(W-121 1,

Spontaneous hemopneumothorax is uncommon, especially among vioincii.
We report a case of spontaneous hemopncumoihorax in a 19-year-old
woman and review seven other cases of spontaneous hemopneumothorax
in women that have been reported in the English language.

ImpniMiiunl of Sleep Apnea in Patients vulh C hriinic Kenal Failure
Who Undergo Nocturnal Hemodialysis — Hanly PJ. Pierralos A. N Engl
J Med 2001 Jan 1 l;.?-i4(2):102-107.

B.'\CKGROLND: Sleep apnea is common in paiicnis wnli cliionic renal
failure and Is not improved by either conventional hemodialysis or peri-
toneal dialysis. With nocturnal hemodialysis, patients undergo hemodi-
alysis seven nights per week at home, while sleeping. Wc hypothesized
that nocturnal hemodialysis would correct sleep apnea in patients with
chronic renal failure because of its greater effectiveness. METHODS:
Fourteen patients who were undergoing conventional hemodialysis for
four hours on each of three days per week underwent overnight poly-
somnography. The patients were then switched to nocturnal hemodialysis
for eight hours during each of six or seven nights a week. They under-
went polysomnography again 6 to 15 months later on one night when
they were undergoing nocturnal hemodialysis and on another night when
they were not. RESULTS: The mean (:::SD) serum creatinine concen-
tration was significantly lower during the period when the patients were
undergoing nocturnal hemodialysis than during the period when they
were undergoing conventional hemodialysis (.^.9il.l vs. I2.8±3.2 mg
per deciliter |342± 101 vs. 1 13 1 ±287 micromol per liter). p<O.00l ). The
conversion from conventional hemodialysis to nocturnal hemodialysis
was associated with a reduction In the frequency of apnea and hypopnea
from 25r 2.5 to 8r 8 episodes per hour of sleep (p = ().03). This reduction
occurred predominantly In seven patients with sleep apnea, in whom the
frequency of episodes fell from 4(i±19 to 9r9 per hour (p=^0.006).
accompanied by increases in the minimal oxygen saturation (from
89.2= 1.8 to 94.1 ~ 1.6 percent. p=0.(X).5). transcutaneous partial pressure
of carbon dioxide (from 38.5^4.3 to 48.3±4.9 mm Hg. p=0.(K16i. and
serum bicarbonate concentration (from 23.22: 1.8 to 27.8r0.8 mmol per
liter. p<0.(X)l). During the period when these seven patients were un-
dergoing nocturnal hemodialysis, the apnea-hypopnea index measured on
nights when they were not undergoing nocturnal hemodialysis was greater
than that on nights w hen they were undergoing niKlumal hemiHllaly sis. but
It still remained lower than it had been dunng the penod when they were
undergoing conventional hemoillalysls (p=0.()5). CONCLUSIONS: Noctur-
nal licinoillaKsis coiTccts sleep apnea associated with chronic renal failure.

CnlTee Consumption and the Risk of Coronary Heart l)i.sea.se and
Death— Klccmola P. Jousilahti P. Plelinen P. Variiainen E. Tuomilehto

J. Arch Intern Med 2000 Dec 1 1 ;1 W)(22|:3.^93-.M(X).

()BJI-;CTIVES: To study prospectively the relation ol collce drinking
with talal and nonfatal coronary heart disease ICHD) and all-cause mor-
tality and to perlorm a cross-sectional analysis at baseline on the asso-
ciation between coffee drinking and CHD risk factors, diagnosed dis-
eases, self-reported symptoms, and use of medicines. METHODS: The
study cohort consisted of 20 1 79 randomly selected eastern Finnish men
and women aged 30 to 59 years who participated in a cross-seclional risk
factor survev in 1972. 1977. or 1982. Habitual coffee drinking, health

Respiratory Care • Man 2001 Vol 46 No 5

457

Abstracts

behavior, major knoun CHI) risk lactor'., ami medical hi>.tor\ were as-
sessed al Ihe baseline examiiuilion. Kach subject was lollowecl up for 10
years alter the survey using the national hospital discharge and death
registers. Multivariate analyses were performed by using the Cox pro-
portional hazards model. RESULTS: In men, the risk of nonfatal myo-
cardial infarction was not associated with coffee drinking. The age-ad-
justed association of coffee drinking was J shaped with CHD mortality
and U shaped with all-cause mortality. The highest CHD mortality was
found among those who did not drink coffee at all (multivariate adjust-
ed). Also, in women, all-cause mortality decreased by increasing coffee
drinking. The prevalence of smoking and the mean level of serum cho-
lesterol increased with increasing coffee drinking. Non-coffee drinkers
more often reported a history of various diseases and symptoms, and they
also more frequently used several drugs compared with coffee drinkers.
CONCLUSIONS: Coffee drinking does not increase the risk of CHD or
death. In men, slightly increased mortality from CHD and all causes in
heavy coffee drinkers is largely explained by the effects of smoking and
a high serum cholesterol level.

Temporal Trends in Outcomes of Older Patients with Pneumonia —

Metersky ML. Talc JP. l-ine MJ. Petnllo MK. .\lcchan TP. Arch Intern
Med 2000 Dec 1 1;I60(22):3385-339I.

BACKGROUND: It is unclear how outcomes of care for patients hos-
pitalized for pneumonia have changed as patterns of health care delivery
have changed during the 1990s. This study was performed to determine
trends in outcomes of care for older patients hospitalized for pneumonia.
METHODS: This retrospective analysis was based on Medicare claims
and included most patients w ith pneumonia who were older than 65 years
and admitted to acute care hospitals in Connecticut between October I .
1991, and September 30, 1997 (fiscal years 1992-1997). We assessed the
trends in hospital costs, discharge destination, hospital mortality rates,
mortality rates within .30 days of discharge, and 30-day readmission rates
for pneumonia. Multivariate logistic regression analyses were u.sed to
adjust for differences in patient characteristics. RESULTS: The mean ( ±
SD) length of stay declined from 1 1.9 ± 1 1.4 days to 7.7 ± 7.2 days
between 1992 and 1997. During this period, adjusted in-hospital mortal-
ity rates declined (p =0.02), while the adjusted risk of discharge to a
nursing facility increased (p<().()()l) and the adjusted risk of hospital
readmission for pneumonia within 30 days of discharge increased
(p =0.05). The adjusted risk of death 30 days after discharge increased,
although the difference was not statistically significant (p =0.09), CON-
CLUSIONS: Between 1992 and 1997, the adjusted risks of mortality
after discharge, placement in a nursing facility, and hospital readmission
for pneumonia increased among older patients hospitalized for pneumo-
nia, in association with a decline in mean hospital length of stay. These
findings raise the question of whether the declining hospital length of
stay has negatively affected patient outcomes.

Out-of-Hospital Cardiac Arrest in Octogenarians and Nonagenari-
ans—Kim C. Becker L. Eisenberg MS. Arch Intern Med 2000 Dec
ll;160(22):.34.39-.3-U3.

BACKGROUND: Studies of elderly patients who have out-of-hospital
cardiac arrest have contradictory results. The studies usually define el-
derly patients as those older than 70 years, and include relatively few
octogenarians and nonagenarians. OBJECTIVES: To compare the sur-
vival after out-of-hospilal cardiac arrest of octogenarians, nonagenarians,
and younger patients and to determine the intluence of age on survival
after adjusting for factors known to intluence out-of-hospital cardiac
arrest outcome. METHODS: We conducted a retrospective cohort stud\
in suburban King County. Washington, on 5882 patients who had out-
of-hospital cardiac arrest from presumed cardiovascular disease between
January 1. 1987, and Deceinber 31, 1998, and who received cardiopul-
monary resuscitation from bystanders, emergency medical technicians, or

both. The main outcome measure was survival to hospital discharge.
RliSULTS: In patients who had out-of-hospiial cardiac arrest due to a
cardiac cause, younger patients had higher hospital discharge rates than
octogenarians, who in turn had higher hospital discharge rates than no-
nagenarians (19.4'7f vs 9.4% vs 4.47^; p<0.(M)l ). However, survival to
hospital discharge improved significantly for younger patients, octoge-
narians, and nonagenarians who had ventricular fibrillation or pulseless
ventricular tachycardia (36% vs 24% vs 17%: p<0.001). After multiple
logistic regression analysis controlling for other factors, increased age
was weakly associated with decreased survival to hospital discharge
(odds ratio. 0.92; 95% confidence interval, 0,85-0.99). CONCLUSIONS:
Octogenarians and nonagenarians have lower survival to hospital dis-
charge than younger patients, but age is a much weaker predictor of
survival than other factors such as initial cardiac rhythm. Decisions re-
garding resuscitation should not be ba.sed on age alone.

The Pathogenesis of .\cute Pulmonary Kdenia .Associated with Hy-
pertension — Gandhi SK, Powers JC, Nomeir AM, Fowle K, Kitzman
DW, Rankin KM, Little WC. N Engl J Med 2001 Jan 4:344(11:17-22.

BACKGROUND: Patients with acute pulmonary edema ofien have
marked hypertension but. after reduction of the blood pressure, have a
normal left ventricular ejection fraction (=: 0..50). However, the pulmo-
nary edema may not have resulted from isolated diastolic dysfunction
but, instead, may be due to transient systolic dysfunction, acute mitral
regurgitation, or both. METHODS: We studied 38 patients ( 14 inen and
24 women; mean [±SD] age, 67± 13 years) with acute pulmonary edema
and systolic blood pressure > 160 mm Hg. We evaluated the ejection
fraction and regional function by two-dimensional Doppler echocardiog-
raphv. both during the acute episode and one to three days after treat-
ment. RESULTS: The mean systolic blood pressure was 200^26 mm Hg
during the initial echocardiographic examination and was reduced to
139±17 mm Hg (p<0.05) at the time of the follow-up examination.
Despite the marked difference in blood pressure, the ejection fraction was
similar during the acute episode (0.50±0.15) and after treatment
(0.50±0.13). The left ventricular regional wall-motion index (the mean
value for 16 segments) was also the same during the acute episode
(1.6±0.6) and after treatment (I.6±0.6). No patient had severe mitral
regurgitation during the acute episode. Eighteen patients had a normal
ejection fraction (at least 0.50) after treatment. In 16 of these 18 patients,
Ihe ejection fraction was at least 0.50 during the acute episode. CON-
CLL'SIONS: In patients with hypertensise pulmonary edema, a normal
ejection fraction after treatment suggests that the edema was due to the
exacerbation of diastolic dysfunction by hypertension - not to transient
systolic dysfunction or mitral regurgitation.

Prehospital Intubation in Patients with Severe Head Injury— Murray
JA. Dcmctriadcs D. Bcrnc TV. Stratton SJ. Cryer HG. Bongard F. et al.
J Trauma 2000 Dec:49(6):1065-1070.

BACKGROUND: Prehospital intubation and airway control is routinely
performed by paramedics in critically injured patients. Despite the ad-
vantages provided by this procedure, numerous potential risks exist when
this is pertormed in the field. We reviewed the outcome of patients with
severe head injury, to determine whether prehospital intubation is asso-
ciated with an improved outcome. METHODS: A retrospective review of
registrv data of patients admitted to an urban trauma center with severe
head in|ur\ (field Glasgow Coma Scale score of <8 and head Abbrevi-
ated Injury Scale score of S3) was performed. Patients were stratified by
methods of airway control performed bv prehospit;il personnel: not in-
tubated, intubated, or unsuccessful intubation. Mortality was determined
for each group. To control for significant variables between these pop-
ulations, matching and multivariate analysis were perfonned. RESL'LTS:
Patients requiring prehospital intubation or in whom intubation was at-
tempted had an increased mortality (81% and 77%. respectively) when

458

Respiratory Care • May 2001 Voi 46 No 5

AHSIU\(TS

cunipurcd wilh noninlubalcil piillciUs (43';4 ). The inortalily lor patient
who had prchospilal iniuhalion pcrromicd did not dciiionslralc an im-
proved sur\i\al usiiij; malchiiii;. hi tacl. iutuhalcd palicnis had a significanll)
higher relative risk (RR) ol monalily sshcn minparcd wilh noniiiluhalion
(RR = l.74,p < ().(X)I) and uiiMitvessriil ijilukilioii p;itiemv (KR 1.5.V
p = O.(X)S) CONCl-l'SION; For ixilienis wilh severe head injur), prehos-
pilal inlutvKion did mil demoiislrale an iinprovemenl in siiiAival. lunher
prospective randomized trials arc necessary to confirm these results.

\n i:\idince-ltasid ( osl-KITeitiMiuss MckUI on Mitlmds ol I'reven-
(iiin of I'listtniiimutic \ enous I hniinlioeniliiiiisiu \ ehii.ihos (If. ( )h
"I'. McCoinhs J. Oder D. J Ir.iuMi.i JDIKI I )cc;4"l(ii: lO.'iy-KXvJ.

BACKGROUND: Venous thrombwmbolism ( VT) alter mjurv is a [luijor
health prohleni. LileraUire dala on melhods nt VT prophylaxis are not
consistent with regard to safely and efficacy, and a recent evidence-based
report could not conclude that any method was superior to any other or
to no prophyla.xis. Because no study exists on the cosl-effecliveness
(C-E) of the different methods of prophylaxis, data from the evidence-
based report were used to design a C-E analysis. This analysis will assist
in the design of future randomi/ed trials with adequate power to show
significant outcome differences. METHOD.S: .\ decision-tree model was
designed on the basis of outcomes from the evidence-based report or
relevant literature. We then calculated the cost of prevention of V I h\
one of the most commonly used methods-low -dose heparin (LDH). low-
molecular-weight heparin (LMWH), or sequential compression devices
{SCDs)-using different probabilities of incidence of VT. Finally, we
adjusted the cost for expected years of life after the episode of VT to
calculate the cost per life-year saved by preventing VT. RESULTS: We
produced two tables that can be used to calculate the cost per life-year
saved for any patient according to his or her age and the method of
prophylaxis used. VT prophylaxis becomes less cost-effective as age
progresses, because of decreased life-expeclancy. With a widely accepted
cost limit of $50,000 per life-year saved to indicate cost-effective treat-
ment, LDH is more cost-effective than LMWH or SCDs. CONCLU-
SION; Our C-E model can help future investigators plan VT-related
research w ith appropriate sample sizes to evaluate cost-effective methods
of prophylaxis. LMWH and SCDs must demonstrate substantial improve-
ments in measured outcomes to be more cost-effective than LDH C-E
inust be incorporated as a primary outcome m future studies comparing
different methods of VT prophylaxis.

\ Survey of Physician Attitudes and Practices Concerning Cost-
EITecliveness in Patient (are — Gmsburg ME. Kravitz RL. Sandberg
WA. West J Med :i)(«l Dec;17.^(6):390-.W4.

OBJECTIVE: To identify physicians' views regarding cost-containment
and cost-effectiveness and their attitudes and experience using cost-ef-
fectiveness in clinical decision making. DESIGN: A close-ended .'iO-item
written survey. SUBJECTS: l,0(K) randomly selected physicians whose
practices currently encompass direct patient care and who work in the
California counties of Sacramento. Yolo. Placer. Nevada, and El Dorado.
Outcome measures Physician altitudes about the role of cost and cost-
effectiveness in treatment decisions, perceived barriers to cost-efteclive
medical practice, and response of physicians and patients if there are
conflicts about treatment that ph\ sicians consider either not indicated or
not cost-effective RESULTS: Most physicians regard cost-effectiveness
as an appropriate component of clinical decisions and think that only the
treating physician and patient should decide what is cost-worthy. How
ever, physicians are divided on whether they have a duty to offer medical
interventions with remote chances of benefit regardless of cost, and they
vary considerably in their interactions with patients when cost-effective
ness is an issue. CONCLUSION: Although physicians in the Sacramento
region accept cost-effectiveness as important and appropriate in clinical

practice, there is little uniformity in how cost-effectiveness decisions are

iinplemcnied

liicreusinu Prevalence ol Miilti(lrut;-Resislaiit Slripnnociii', piicii-
mimiae in the United States — Whitney CG. Farley MM. Hadler J. Har-
rison Lll, Lexau C. Reingold A. et al. N Engl J Med 2()<K) Dec 28;
.14.1(261:1917-1924.

BACKGROUND: The emergence of drug-resistant strains of bacteria has
LiMTiplicated treatment decisions and may lead to treatment failures.
Ml' IIIODS: We examined dala on invasive pneumococcal disease in
patients identified from 199.S to I99S in the Active Bacterial Core Sur-
scillance program of the Centers for Disease Control and Prevention.
Pneumococci thai had a high level of resistance or had intermediate
resistance according to the definitions of the National Committee for
Clinical Laboratory Standards were defined as "resistant" for this anal-
ysis. RESULTS: During 1998. 401.1 cases of invasive Sin-punoccus
imeiinumitw disease were reported (2.1 cases per l(K).(KX) population):
isolates were available for -147.S (X7 percent). Overall. 24 percent of
isolates from 1998 were resistant to penicillin. The proportion of isolates
that were resistant to penicillin was highest in Georgia (.1.1 percent) and
Tennessee (.l.'i percent), in children under five years of age (.12 percent.
vs. 21 percent for persons five or more years of age), and in whites (26
percent, vs. 22 percent for blacks). Penicillin-resistant isolates were more
likely than susceptible isolates to have a high level of resistance to other
antimicrobial agents. Serotypes included in the 7-valenl conjugate and
2.1-valenl pneumococcal polysaccharide vaccines accounted lor 78 per-
cent and SS pcrcenl of penicillin-resistant strains, respectively. Between
199.i and 199S (during which period 12.04.5 isolates were collected), the
proportion of isolates that were resistant to three or more clas.ses of drugs
increased from 9 percent to 14 percent: there also were increases in the
proportions of isolates that were resistant to penicillin (from 21 percent
to 2.5 percent), cefotaxime (from 10 percent to 14 percent), meropenem
(from 10 percent to 16 percent), erythromycin (from II percent to 15
percent), and trimcthoprim-sulfamelhoxa/ole (from 25 percent to 29 per-
cenll. The increases in the frequency of resistance to other antimicrobial
agents occurred exclusively among penicillin-resistant isolates. CON-
CLUSIONS: Multidrug-resistant pneumococci are common and are in-
creasing. Because a limited number of serotypes account for most infec-
tions with drug-resistant strains, the new conjugate vaccines offer
protection against most drug-resistant strains of i". imeumoniae .

PulnwmaiTi Hypertension— Gaine S. JAMA 2000 Dec 27;284<24):.1 160-.1168.

.A clinically useful, irealmcnt-based classification of pulmonary hyper-
tension divides the disease into 5 distinct categories: (I) pulmonary hy-
pertension associated with disorders of the respiratory system and/or
hypoxemia: (2) pulmonary vemius hypertension: (.1) chronic thrombo-
embolic disease; (4) pulmonary arterial hypertension: and (5) pulmonary
hypertension due to disorders directly alfecting the pulmonary vascula-
ture. Pulmonary arterial hypertension includes individuals with primary
pulmonary hypertension, congenital heart disease, connective tissue dis-
ease, and liver disease. These heterogeneous diseases have similar char-
acteristic pathological changes, including in situ thrombosis, smooth mus-
cle hypertrophy, and intimal proliferation. Right heart catheterization is
essential lo confirm diagnosis, determine prognosis, and assign therapy.
.\ minority ol patients have a favorable response to an acute vasodilator
trial and long-lcrm benefit wilh calcium channel blocker therapy. Con-
linuous intravenous epoprostenol improves sympumis and survival in
palicnis with advanced primary pulmonary hypertension and has poten-
tial benefit in other forms of pulmonary arterial hypertension. Lung trans-
plantation remains an important option for individuals in whom maximal
medical therapy fails. The recent discovery of the gene for familial pri-
mary pulmonary hypertension and the increase in new drugs undergoing
clinical trials arc encouraging developments.

Respiratory Care • M \-i 2001 Vol 4(i No .*>

459

Original Contributions

Effect of Inner Cannula Removal on the Work of Breathing
Imposed by Tracheostomy Tubes: A Bench Study

Tony Cowan RRT CPFT, Timothy B Opt Holt EdD RRT. Cyndi Gegenheimer RRT,
Seth I/enbcrg MD, and Pandurang Kulkarni PhD

BACKGROUND: Tracheotomy has been used to assist in weaning patients from mechanical ven-
tilation. Some patients fail to be weaned from the \entilator despite tracheostomy. VVc hypothesized
that removing the inner cannula from the traclieostomy tube would decrease the tube's imposed
work of breathing (VV()B,m|.). MP:TH0DS: The hypothesis was tested using a lung model, by
measuring the change in WOB,^,,, when the inner cannula was removed. A mechanical lung model
was developed using a test lung to simulate a spontaneously breathing patient. \\OB,^„. was
measured with a commercially available lung mechanics monitor. Shiley size 6. 8, and 10 nonfenes-
trated tracheostomy tubes were tested with the inner cannula in and out. Breathing conditions were
simulated using tidal volumes (\j) of 300 and 500 niL matched with breathing frequencies of 12,
24, and 32 breaths per minute, by using a ventilator to simulate spontaneous breathing through one
side of the test lung. RESULTS: Under all the tested breathing conditions, VVOB,;^,,. for each of the
3 tracheostomy tubes was significantly reduced (p < 0.05) when the inner cannula was removed.
Also, as simulated spontaneous inspiratory flow demand increased (ie, as V^ and/or frequency were
increased), VVOB,;^,,. also increased, and vice versa. With the cannula removed, VVOB|m,, was not
significantly different between the size 6 and 8 tubes nor between the size 8 and 10 tubes when Vf
was 300 mL and frequency was 12 breaths per minute. CONCLUSIONS: There was a significant
decrease in WOB,Mp with each tube when the inner cannula was removed. WOB|,^,,, increased with
an increase in inspiratory flow demand (ie, increase in Vp and/or frequency), as well as when tube
size decreased, in weaning a tracheostomized patient from mechanical ventilation, increasing the
internal diameter of the tube by removing the inner cannula may be beneficial. Further study is
needed to determine if these findings are clinically important. Key words: ainvay irsisiaiuc. BiCorc
pulnumarx numitor. pulmomiry monitonng. tracheostomy, ventilator weaning, weaning, work of breath-
ing, puhnaiuiry nieiliiinics. [Respir Care 2001;46(5):46() — 165]

Background

Tracheotomy is a common surgical procedure for inten-
sive care patients.' The goals of tracheotomy are to bypass
the upper airway, facilitate removal of tracheobronchial
secretions, prevent aspiration of gastric contents, and to

Tony Cowan RRT CPFT. Timoth\ B Opt Holt FdD RRT. and Cyndi
Gegenheimer RRT arc alfillaled «ith the IX'partmcnt of C;irdiorespirator\
Care; Seth Izenbcrg MD is affiliated with the Depanmenl of Surgery; and
Pandurang Kulkarni PhD is affiliated with the Department of Mathematics
and Statistics. University of South Alabama. Mobile. Alabama.

This research was presented at the open forum of the 44th International
Respiratory Congress of the American Association for Respiratory Care,
November 7-10, 1998. Atlanta. Georgia.

control the airway for prolonged mechanical ventilation.' ■*
Despite known disadvantages of tracheotomy, which in-
clude tracheal stenosis at the stoma site, increased bacte-
rial colonization of the airway, and prolonged tracheal
cannulalion, tracheostomy tubes provide a number of ad-
vantages over endotracheal tubes.^ " In the event of pro-
longed ventilation, tracheostomy tubes provide improved
patient mobility and comfort, improved secretion clear-
ance, increased airway security, relief from worsening glot-

The authors of this manuscript have no involvement, financial or other-
wise, with any organization that might have direct financial interest in the
subject discussed herein.

Correspondence: Tony Cowan RRT CPFT, 1517 .North Dnltwuod Dnve.
Mobile AL 3660.'i. E-mail: Mucomist@email.com.

460

Rlspiraiokv Cari: • May 2001 Vol 46 No 5

Effect of Inner Canui.a Rumoval on Work of Breathing

I'ulnioiiaiy Monitor

Balloon
Catheter

To Ventilator

Tracheostomy
Tube

TTL

Fig. 1. Lung model used to measure imposed resistive worl< of breathing in tracheostomy tubes with the cannula in and out. TTL
training/test lung.

tic and subglottic stenosis, relief lYom worsening oropha-
r\ngeal and lar> ngcal damage, and perhaps fewer days of
mechanical ventilation.' ^ '"^ Ventilator-dependent patients
better tolerate weaning with tracheostomy tubes than en-
dotracheal tubes, because tracheostomy offers lower air-
way resistance and up to 50% less dead space, making
spontaneous breathing considerably easier."'-^'*

We ha\e observed failure to wean from ventilation in
some patients who have tracheostomies. If a method can
be introduced to promote successful weaning, more pa-
tients may be liberated from mechanical ventilation faster
and with less stress.

A comparison of the imposed resistive work of breathing
(WOB) of a tracheostomy tube with the inner cannula in
place and with the inner cannula removed has not previouslv
been reported. The difference in the imposed WOB ( WOBi^,,,)
between these two conditions needed to be measured to de-
termine if removing the inner cannula would lower WOB, ^,|>.
The purjx)se of this study was to determine if removal of the

inner cannula of a tracheostomy tube in a lung model causes
a significant decrease in WOB|\,,,.

Materials and Methods

A mechanical model of the lung and airway (Fig. 1 ) was
assembled using a commercially available training/test lung
(26001 PneuView Dual Adult Testing and Training Sys-
tem. Michigan Instruments. Grand Rapids. Michigan).
Shiley adult tracheostomy tubes (Mallinckrodt. Irvine. Cal-
ifornia) were connected to the right side of the 2-chamber
test lung by inserting the distal end of the tracheostomy
tube into an adapter that connected to the test lung's 15
mm connector. The tracheostomy tube cuff was inflated as
needed to create an air-tight seal. A lift bar was attached to
the left test lung chamber, which was ventilated by a time-
cycled, volume-limited ventilator (Emerson 3MV-PED
ventilator. JH Emerson. Cambridge. Massachusetts). The
ventilator delivered tidal volumes ( V^^) of 500 and 300 mL

Respiratory Care • May 2001 Vol 46 No 5

461

Effect of Innf:r Canula Rfmovai. on Work oi Breathing

at frequencies of 12, 24. and 32 breaths per minute, with
a sinusiiidai inspiratory tlow waveform. The inhalation-
to-exhalation time ratio was maintained at 1:2 by setting
the inspiratory tinie lo 1 .67 seconds, 0.84 second, and 0.63
second, respectively. Inspiratory flow varied with fre-
quency. V^. and inspiratory time. Each frequency was
matched with the specified V , to simulate 6 conditions of
quiet, moderate, and labored breathing; V , of 500 and 300
niL were paired with a frequency of 12 breaths per minute
to simulate quiet breathing conditions; V^- of 500 and 300
mL were paired with a frequency of 24 breaths per minute
to simulate moderate breathing ct)nditions: and V^ of 500
and 300 niL were paired with a frequency of 32 breaths
per minute to simulate labored breathing conditions. Each
\ I and frequency was verified using a calibrated pulmo-
nary mechanics monitor (BiCore CP-IOO. Allied Health-
care Products, .St Eouis. Missouri).

The pulmonary mechanics monitor was used to measure
the airway pressure drop at the carinal (distal) end of the
tracheostomy tube and V, for calculation of WOBi;^,,,.
This was done by attaching a I mm internal-diameter,
air-filled silastic catheter, attached to the pulmonary me-
chanics monitor, to the distal end of the tracheostomy tube
to measure the pressure drop (below baseline). Also, a
flow transducer was attached to the proximal end of the
tracheostomy tube to measure flow. The pulmonary me-
chanics monitor integrates tlow. resulting in a Vj mea-
surement.

The pulmonale mechanics monitor has a built-in balloon
integrity test that is conducted before the monitor will allow
any WOB measurements to be made. When using an esoph-
ageal balloon catheter in a patient, checking the integrity of
the balloon is useful. If the balloon's integrity is compro-
mised while in the esophagus, the accuracy of the pressure
readings may be affected by partially or totally blocked pres-
sure port.s. However, in this model, the balloon would have
hindered the nonesophageal pressure readings and was there-
fore removed. In order to bypass the balloon integrity test, we
placed a 3-way stopcock in the pressure measurement line.
The extension tubing from the monitor was cut and the se\ -
ered end was connected to the proximal port of the stopcock.
The connector of an esophageal balloon catheter was cut off.
and the severed end of the balloon catheter was connecteil lo
the middle port of the stopcock. (Jnc end of the air-filled.
silastic catheter was connected to the distal port of the stop-
cock, and the other end was put through an opening in the
adapter near the distal end of the iracheosionn lube (see Fig.
I ). The open area around the catheter in the adapter was
sealed with silicone gel. This was similar to the method de-
scribed by Banner et al.'' lo switch between esophageal pres-
sure and carinal pressure w hen allemaling between measure-
ments of patient WOB and WOBi^,,,. respectixcK . Instead of
switching between 2 sites for pressure measuiemcnis. ihe
stopcock was used to switch between the balloon catheter ami

Total Work of
Breathing

Physiologic
Work

Flow-Resistive
Work Imposed
by the

Tracheostomy
Tube

Hlaslic Work

Flou-

Tissue and
Chest Wal

Work of Ihe
Airways

Fig. 2. In a spontaneously breathing patient with a tracheostomy
tube, the total work of breathing is composed of physiologic work
(including the elastic work of the lung and chest wall) and flow-
resistive work imposed by the tracheostomy tube.

the silastic catheter used to measure the pressure drop al the
distal end of the tracheostomy tube. The esophageal balloon
catheter port was turned on when the monitor conducted the
balloon integrity test. After the test was finished, ihe port lo
the silastic calheler was opened, allowing the iiu)nitor to re-
ceive pressure readings from the disial end of the tracheos-
tomy tube.

Total WOB (WOB,,,y) is composed of physiologic WOB
(WOBpHvs). which includes elastic work of the lung tissue
and chest wall and flow-resistive work of the airways, and
WOB|M,,. which is the flow-resistive wcirk of the breathing
device (Fig. 2).'" The WOBi^,,, of the tracheostomy tube was
calculated by using the following adapted equation:

WOB,„p

(IV

wherein P,-, is the pressure drop at the distal end of the
tracheostomy tube and dV is the change in ndIuiuc." Shiley
tracheostoniN tube sizes 6. 8. and 10 were used in this
study. Dunne the portion of the siud> where the inner
cannula was removed, the tracheostonn tube was attached
to the How transducer afier remo\ing the inner cannula
from the 15 mm connector and reattaching the connector
to Ihe tracheoslom\ tube. .Silicone gel was applied to the
outside of the ciiniiector once it was reattached to the
iracheostoms tube, to establish an airlighi seal. Applying
silicone-gel to the tracheostom\ tube of a patient is not
jiractical and could even pnne ha/aidous. .Although find-
ing a safe method of attaching a flow iransducer to a
noncannulaied irachet)stomN tube pro\es complicated, we
believe this obstacle can be inercome.

.All measuivmciiis were made al room temperature. Fluc-
iLiations in barometric pressure and humiditv were not taken
mto consideration. .A constant test lung compliance of 0.04
L/cm H,() was maiiiUiined throuehoul the stud>.

462

R^.s^iRAioK^ C'aki. • Ma^ 2001 Vol 40 No 5

Effhci oi Inm k Cani'ia Kim(i\ \i, on Work oi liui aiming

1.2 -T

>=^0 8

03
O

6 04

6 8 10
500 32

8 10

6 8 10
300:24

6 8 10
500,12

6 8 10
30012

6 8 10
300 32 500:24

Tube Size and Tidal VolumeRate
Fig. 3. Imposed work of breathing (WOB) for Shiley size 6. 8. and 10 tracheostomy tubes, with tidal volumes of 500 and 300 mL and
respiratory rates of 12, 24. and 32 breaths per minute. Black bars denote WOB with the cannula in place. Clear bars denote WOB with the
cannula removed.

The WOB, MP was measured for each tube, under each
simulated breathing condition with the cannula in and out.
This was achieved by using the puiinonar\ monitor's
numeric data mode, which provided a breath-by-breath
analysis of WOB. Unfortunately, similar to Blanch and
Banner,'- the pulmonary mechanics monitor we used did
not directly measure WOB|m,,. Instead, patient WOB or
WOBjoT ^^''^ measured and displayed on the monitor.
Correction factors of 0.06 J/L per .'iOO rnL of V-^ (elastic
work required to intlate the respiratory system) and 0.02
J/L per 300 mL of V , were subtracted from each measured
total WOB value to mathematically derive WOBim,,. As
reported by Blanch and Banner,'^ for the BiCore CP-100
respiratory monitor, a correction factor is needed to avoid
overestimating the reported WOBi^,,, for a model in which
the elastic work of the chest wall is not a factor

In patients, the BiCore monitor uses the Campbell
diagram to calculate WOB,,,,.'" The BiCore reports
WOB-roT by integrating pressure drop and V^, creating a
pressure-volume loop. The area under the pressure-volume
loop is the resisti\e and elastic work needed to intlate the
lungs; however, it does not account for all of the elastic
work needed to expand the entire respiratory system. To
include the missing elastic work, the monitor uses a pro-
grammed chest wall compliance (200 mL/cm H2O) and
measured V, to calculate the approximate missing elastic
work, then adds that value to the wurk measured in the
area of the pressure-volume loop. Since chest wall com-
pliance was not a factor in our model, this added approx-
imation for elastic WOB of the chest wall was subtracteti.

Otherwise.

reported.

ly high WOB|„

would ha\e been

The average WOB,mp (corrected) from 10 consecutive
breaths was used in calculating the results. The final mean
WOB|m|, \alues within each test were compared statisti-
cally with 4-way analysis of variance. Since interactions
were significant, multiple comparisons were analyzed us-
ing Tukey"s Honest Significant Difference test, with an
overall significance level of alpha < 0.05. Using this
method, any 2 means are declared significant if the abso-
lute difference in the means is greater than 0.025 J/L.

Results

Imposed resistive WOB decreased significantly when
the inner cannula was removed from Shiley size 6. 8, and
10 tracheostomy tubes under simulated quiet, moderate,
and labored breathing conditions. Also, as inspiratory fiow
demand increased, imposed resistive WOB increased sig-
nificantly with each tube (Fig. ? and Table 1). During the
lowest level breathing condition (300:12). there was an
insignificant difference in WOBi^,,, between the size 6 and
8 tubes with no cannula. This was also true for the size 8
and 10 tubes under the same conditions.

Discussion

Weaning patients from mechanic.il \cnlilation can be a
challenging and sometimes cimibersome task. Patients w ith
compromised pulmonary function may take weeks to lib-
erate from mechanical \entilation. Fortunately for the pa-
tient, tracheostomy may facilitate weaning, decreasing the
number of ventilator days.' '•"'* Tracheostomy tubes offer

Respiratory Care • Mav 2001 Vol 46 No 5

463

Effect of Inner Canula Removal on Work of Breathing

Hiblc 1. Inipiisc!.! VS'iiik of Brcatlunj: loi Shilcy Size 6. 8, and 10
TrachcoMomy Tubes Under 3 Bieaihiiig Patterns*

WOBiMp (J/L)

Vitf

Shiley size 6

Shiley size 8

Shiley size 10

500:32

1.04 ±0.007

0.66 ±0.013

0.49 ± 0.005

0.67 ± 0.014

0.47 ± 0.007

0.37 ± 0.(H)8

300:32

0.49 ± 0.005

0.32 ± 0.005

0.26 ± 0.003

0.30 ± 0.00')

0.26 i 0.007

0.21 1 ().(X)7

500:24

0.61 ± 0.003

0.46 >: 0.005

0.34 ± 0.008

0.3') i O.OOS

0.32 ± 0.000

0.27 ± 0.003

300:24

0.34 i 0.005

0.23 ± 0.004

0.19 ± 0.003

0.21 ± 0.005

O.iy ± 0.005

0.16 ± 0.005

500:12

0.25 ± 0.006

0.19 ± 0.005

0.15 ±0.003

0.17 ± 0.00')

0.14 ± 0.007

0.11 ± 0.020

300: 1 2

0.14 ± 0.007

0.09 ± 0.007

0.06 ± 0.006

0.06 i 0.003

0.05 ± 0.009

0.03 ± 0.011

WOBiMp = imposed work of hri'alliiiig.

Vy = lida! volume.

f = respirdlory frequency.

C = cannula.

NC = no cannula.

•WOBivip for Shiley si/e 6. S. and 11) traelieosloiny tuhes under ?• brealhing pallems thai

simulate labored, moderate, and quiet breathing eondnmns Means and standard deviations

were calculated from 10 breaths obtained by the Bieore CP-KHI monitor. Removal of the

inner cannula resulted in a statistically significant (p •- ().t).S) decrease tor each tube under

each VjS combination. Any 2 means are declared significant if the absolute difference in the

means is greater than 0.02.S J/L. using Tukey's Honest Significant Difference test.

less dead space and airway resistance liian endotracheal
tubes, thereby lowering WOB and making spontaneous
breathing easier.-"* '■* We hypothesized that removal of the
inner cannula would decrease WOBi^,,,. We believe this
would facilitate weaning in the clinical setting.

.Although there is no literature addressing WOB|Mp of
trachcosttimv tubes v\ ith the inner cannula removed, there
have been studies conducted on WOBi^^,, of tracheostomy
tubes and artificial airv\ays in general. In one study com-
paring the imposed WOB of endotracheal and tracheos-
tomy tubes in a lung model, the WOBim,, in a tracheos-
tomy tube was found to be lower than in an endotracheal
tube with the same internal diameter. '■* This was more
pronounced vsilh increa.sing flow rates. Increased resis-
tance caused by increasing turbulent flow and longer tube
length were suggested reasons for these findings. These
observations were consistent with PoiseuilIe"s law. which
indicates that under certain conditions, changes in pressure
vary directly with tube length and tlow.

Bolderetal'-'* measured WOB|m|, with endotracheal tubes
in a lung model and found a ?i4-\549t increase in WOB
with only a 1.0 mm decrease in internal diameter. Resis-
tance may be even higher in patients with these tubes
because of the addition of secretions antl the thermolabil-
ity of the plastic."

Similarly. Mullins ct al"' measured the resistance and
WOB in tracheostomy tubes antl found that WOB de-
creased with increasing internal diameter of the lube. It
was notetl that increases in respiratory rale and V, are
essenlially dilTerenl methods of increasing How and arc
directly associated with increased WOB. It was also sug-
gested that, to facilitate weaning a tracheostomized patient
from mechanical ventilation, selecting a tube that opti-
mally lowers imposed WOB is critical for success.

In all the conditions considered, our results indicate that
statistically significant reductions in iniptised resistive
WOB can be achieved by removal of the inner cannula.
Even during the lowest simulated breathing condition, when
the imposed WOB was minimal to start with, the reduction
achieved by removing the inner cannula was significant.
The reductions generally became more prominent as Vj
and frequency increased. It was also clear that as the in-
spiratory tlow demand decreased, a statistically significant
decrease was observed in WOBn^n,. Furthermore, under
each condition considered in our studv . WOBi^,,, decreased
significantly as the tube size was increased, except when
Vj was 300 ml. and frequency was 12 breaths per minute,
which yielded an insignificant difference in W'OBi^,,. be-
tween the size 6 and 8 tubes and the size 8 and 10 tubes,
with the cannula removed.

The normal range of physiologic WOB in the adult
patient is 0.3-0.6 J/L.'^ In patients on partial ventilatory
support with WOBp^vs values greater than 0.75-0.80 J/L,
weaning is unlikely to be successful.'^"* Kirton et al"*
demonstrated that intubated patients with an unacceptably
high WOB,,,, (ie. 1.6 ± 0.83 J/L) and a WOB^hys less
than 0.80 J/L could be successfully extubated. WOB,^,p
was often twice that of WOBpHvs- meaning that WOBi;^,,,
can masquerade as ventilator weaning intolerance. Un-
fortunately for the tracheostomized patient weaning from
mechanical ventilation, complete decannulation is not an
option to alleviate the hindering effects of WOBi^jp of
the tracheostomy tube. Therefore, it is our opinion that
WOB,,,, must be less than the acceptable WOBp,,Ys (ie.
less than 0.73-0.80 J/L) to promote successful weaning in
the tracheostomized patient. If resistive WOB imposed by
the inner cannula can be eliminated during weaning to
achieve WOBpoy values less than 0.7.3-0.80 J/L. weaning
may be facilitated.

WOB|v,|, decreased as tube size increased and inspira-
tory flow demand (V, or frequency) decreased, with and
without the cannula. The hard-to-wean patient may ini-
tially exhibit a labored breathing pattern resulting in a
greater than normal WOBp,,,, s- In addition, if the patient
has a small liachcostomy tube, high levels of WOBi^p
would make weaning even more difficult and prevent suc-
cess in weaning.

If a patient has a near but higher than normal VVOBp,,^s
during weaning trials, the imposed WOB b\ the inner

464

Rfspirator^ Cari: • May 2001 Vol 46 No 5

Effect of Inner Canula Removal on Work oi Ureathing

caiiiuil.i ctuiKI cause ucaniiiy I'ailuiv li\ iiiLicaMM;j WOH
TOT 'o greater than ().75-().S{) J/1. This uoiild especially
hold true lor the si/e 6 and S tubes under certain condi-
tions. \\ hen V I was 500 nil. and Irequenc) was 32 breaths
per minute, removing the inner cannula significantly re-
duced the \VOB,M,,: by 369; (().(i7 J/l, \s 1.04 J/L) with
the si/e b lube; by 289^ (0.47 J/L vs 0.66 J/L) with the si/e
8 tube: and by 24''/, (0.37 J/L vs 0.4^; J/L) with the si/e 10
tube. Although the WOB,^,,, remained high (0.67 J/L) with
the size 6 tube alter cannula removal, a patient exhibiting
a low VVOB|.,,,,s f^i" '' h'g'i WOB,,,t. due to a high
WOB|\,|,. may achieve an acceptable WOBt^„t^ for wean-
ing after cannula removal. Similarly, when V^ was 500
mL and frequency was 24 breaths per minute, the WOBi^,,
decreased significantly after inner cannula removal; by
36% (0.39 J/L vs 0.61 J/L) with the size 6 tube; by 30%
(0.32 J/L vs 0.46 J/L) with the size 8 tube; and by 21%
(0.27 J/L vs 0.34 J/L) with the size 10 tube. The WOB,;,,,,
was practically the same for the size 8 and 10 tubes with
the inner cannula in place when Vp was 300 mL and
frequency was 12 breaths per minute. This indicates the
potential that removing the inner cannula can decrease
WOB-i-QT to an acceptable range for promoting weaning,
by decreasing WOB,^,,..

The tracheostomy tube w ilh the largest internal diame-
ter is desirable to minimize WOB|.^,|, Our data re\eal that
by removing the inner cannula, \VOB|^,p is significantly
(p < 0.05) reduced under all tested conditions. This is
most likely due to the resultant increase in the lumen di-
ameter with inner cannula remo\ al. In the patient for whoin
weaning seems most difficult or unlikely, the reduction in
WOB,^,p offered by removing the inner cannula and thus
increasing the internal diameter may be the edge the pa-
tient needs for successful weaning.

This bench study included the typical range of breathing
conditions found in patients being weaned from the ven-
tilator. Extraneous variables such as poor pulmonary hy-
giene, presence of mucus in the tracheostomy tube, and
over-hydration \ ia high-flow oxygen delivery devices, are
difficult to simulate and. consequently, were not integrated
into the lung model.

Conclusions

The imposed WOB was measured in .Shiley size 6, 8.
and 10 tracheostomy tubes v\ith and v\ithout the inner
cannula in a lung model. In this sluils, W'OBi^n, increased
with increases in V, and Irequencs, as well as when tube
size decreased. WOB,;^,,, decreased significantly in all lubes

when the mner cannula was removed, regardless of in-
spiratory How demand. In weaning a tracheostomizcd pa-
tient with marginal pulmonary function and reserve, in-
creasing the inner diameter of the tube by removing the
inner cannula during spontaneous breathing trials may be
beneficial. Clinical studies are needed lo determine il these
findings are important lor the |iatienl.

REFERKNCE.S

1. HclTncr JE. Medical indications for Iracheolomy. Chest 1989,96(1):
I8f>-I9().

2. Hooper M. Nursing care ot the palienl willi a tracheostomy. Nurs
.Stand iyy6;l()(.14):40-l3.

^. Allan D. Patients with an endotracheal lube or tracheostomy. Nurs

Times l984;80(l.^):36-38.
4. Allan D. Making sense of tracheostomy. Nurs Times I987;83(45):

36-38.
.S. .Sugerman HJ. W'olte L. Pasquale MI). Rogers FB. 0"Malley KF.

Knudson M. et al. Multicenter. randomized, prospective trial of early

tracheostomy. J Trauma 1 W7;43(.'i):741-747.

6. Helfner JE. Miller KS. .Sahn SA. Tracheostomy in the intensive care
unit. Part 1: indications. techni(.|uc. management. Chest 1986:90(2):
269-274.

7. Maziak ED, Meade MO, Todd TRJ. The timing of tracheostomy: a
systematic review. Chest 1998:1 1 4(2):60.'>-^09.

8. Gunawardana RH. E.xperienee with tracheostomy in medical inten-
sive care patients. Postgrad Med J 1992:68(799):338-341.

9. Banner MJ, Kirby RR. Blanch PB. .Site of pressure measurement
during spontaneous breathing with continuous positive airway pres-
sure: effect on calculating imposed work of breathing. Crit Care Med
1992;2(}(4):528-533.

10. Banner MJ. Kirby RR. Blanch PB. Diflerentiatmg total work of
breathing into its component parts. Chest 1996:109(5):! 141-1 143.

1 1 Banner MJ. Kirby RR. Blanch PB. Layon AJ. Decreasing imposed
work of the breathing apparatus to zero using pressure-support ven-
tilation. Crit Care Med 1993:21(9):133.3-1338.

12. Blanch PB. Banner MJ. Is tracheal pressure ventilator control com-
parable 10 an equivalent level of pressure support venlilalion ' Respir
Care 1997:42(111:1022-1033.

13. Banner MJ. Kirby RR. Gabrielli A. Blanch PB. Layon AJ. Partially
and totally unloading respiratory muscles based on real-time mea-
sureiTients of work of breathing: a clinical approach. Chest 1994:
106(6): 1 835- 1842.

14. Davis K Jr. Branson RD. Poremhka 1). .-X comparison of ihe imposed
work of breathing with endotracheal and tracheostomy tubes in a
lung model. Respir Care 1994:.^9(6):61 1-616.

15. Bolder PM. Healy TEJ. Bolder AR. Beatty PC. Kay B. The extra
wiirk of breathing through adult endotracheal tubes. .Anesth Analg
19S6.ft5(S):853-859.

16. Mullins JB. Tempter JW. Kong J. Da\is V\ E. Hinson J. ,-\invay
resistance and work of breathing in tracheostomy tubes. Laryngo-
scope 1993: 103(1 2): 1367-1.372.

17. Marini JJ. Strategies to minimize breathing effort duiHng mechanical
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IS. Kirton OC. DeHaven CB. Morgan JP. Windsor J. Civetta JM. Ele-
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ing intolerance. Chest 1995:108(4):I02I-I()25.

Respiratory Cari; • MA"* 2001 Vol 46 No 5

46.^

Electrical Stimulation for Swallowing Disorders Caused by Stroke

Marcy L Freed MA SLP, Leonard Freed PhD, Robert L Chatburn RRT FAARC,

Michael Christian MD

BACKGROUND: An estimated 15 millicm adults in the United States are affected by dysphagia
(diftKiiitN swallowing). Severe dysphagia predisposes to medical complications such as aspiration
pneumonia, bronchospasm, dehydration, malnutrition, and asphyxia. These can cause death or
increased health care costs from increased severity of illness and prolonged length of stay. Existing
modalities for treating dysphagia are generally ineffective, and at best it may take weeks to months
to show improvement. One common conventional therapy, application of cold stimulus to the base
of the anterior faucial arch, has been reported to be somewhat effective. We describe an alternative
treatment consisting of transcutaneous electrical stimulation (ES) applied through electrodes placed
on the neck. OB,IECTIVE: Compare the effectiveness of ES treatment to thermal-tactile stimula-
tion (TS) treatment in patients with dysphagia caused by stroke and assess the safety of the
technique. METHODS: In this controlled study, stroke patients with swallowing disorder were
alternately assigned to one of the two treatment groups (TS or ES). Entry criteria included a
primary diagnosis of stroke and confirmation of swallowing disorder by modified barium swallow
(MBS). TS consisted of touching the base of the anterior faucial arch with a metal probe chilled by
immersion in ice. ES was administered with a modified hand-held battery-powered electrical stim-
ulator connected to a pair of electrodes positioned on the neck. Daily treatments of TS or ES lasted
1 hour. Swallow function before and after the treatment regimen was scored from (aspirates own
saliva) to 6 (normal swallow) based on substances the patients could swallow during a modified
barium swallow. Demographic data were compared with the I test and Fisher exact test. Swallow
scores were compared with the Mann-Whitney U test and Wilcoxon signed-rank test. RESULTS:
The treatment groups were of similar age and gender (p > 0.27), co-morbid conditions (p = 0.0044),
and initial swallow score (p = 0.74). Both treatment groups showed improvement in swallow score,
but the final swallow scores were higher in the ES group (p > 0.0001). In addition, 98% of ES
patients showed some improvement, whereas 27% of TS patients remained at initial swallow score
and 11% got worse. These results are based on similar numbers of treatments (average of 5.5 for
ES and 6.0 for TS, p = 0.36). CONCLUSIONS: ES appears to be a safe and effective treatment for
dysphagia due to stroke and results in better swallow function than conventional TS treatment. Key
words: swallowing, dysphagia, electrical siiniulalion. stroke, modified hariuni swallow. [Respir Care
20()1:46(5);466-4741

Background

An estimated 15 million adults in the United States' are
affected by difficulty in swalknving (dysphagia). The prev-

alence of dysphagia in certain diseases may approach 90%
(eg. amyotrophic lateral sclerosis. Parkinson's disease, and
certain types of stroke).- Severe dysphagia predisposes to

Marcy L Freed M.\ SLP is atTllialed with Universitv Hospitals ol Cleve-
land (formerly Hillcrest H()spilal/Clc\ eland Clinic Health Systems),
Cleveland. Ohio. Leonard Freed PhD is alTiliated with the Department ol
Zoology. University of Hawaii, Honolulu. Hawaii. Robert L Chatburn
RRT FAARC is affiliated with the Department of Respiratory Care.
University Hospitals of Cleveland. Cleveland. Ohio. Michael Christian
MD is affiliated with the Department of Radiology. Hillcrest Hospital.
Cleveland. Ohio.

Members of the research team have applied for and recei\ ed a patent on
the technique and de\ ice described herein, w ilh further claims now pend-
ing. As of this date, there has been no mone\ promised or received from
any business group. The study was funded m total by the authors and the
research team.

Correspondence: Marcy L Freed M.'\ SLP. Respiratory Care Department.
University Hospitals of Cleveland. 1 1 KXl Euclid .ALvenue. Cleveland OH
44106. E-mail: marcv.frcedS'uhhs.com.

466

Ri spiRATORV Care • Ma^ 2()(J1 Vol 46 No 5

Electricai Sii\u I \ii()n iok Swaii owing Disordf.rs

mciliciil complications sia li ;is aspiration pTiciimunia. bron-
chospasiii. licliMliation. inalmiiiiiion. ami asphwia. ThcM."
can cause ilcalh or mctcascd health care costs IVoni in-
crcascil scNcritv of illness, proloiijjeil len^'lh ol sia\. read-
missions, rcspirator\ support. traclieotoni\, and percuta-
neous enterostomal ;jastric li'IXi) tuhe placement plus
related nutritional supplements and ei|Liipment.- ■^ Aside
from the ph\sical comjilicaiions ot aspiration, patients of-
ten snller severe dejiression because of the loss of the
swallow lunclion and ihe disruption ol normal acln ilies of
daily living.

Existing treatments for d\ sphagia are unable to restore
complete swallow function in patients with the most se-
vere disorders. Phvsical maneuvers to compensate for the
deficiency (such as tucking the chin and suck swallow ) are
considered gcnerallv ineffective.'^'' Thermal-tactile stimu-
lation (T.S) (ie. application of cold to the anterior faucial
arch'-") and biofeedback" have success rates ranging from
0% to 83%.^'* " Studies reporting high success rates with
stroke patients gcnerallv do not include the most severe
forms of dysphagia, in which patients iniliallv aspirate
evervlhmg. including their own saliva. Often, these studies
simpiv state that improvement was resumption of oral in-
take, but they do not describe the coiisisiencv of the oral
intake. The type of oral intake is important because it
affects not only hydration and nutrition hut also the psy-
chosocial impact on the patient. The minimum goal of
treatment should be to achieve sufficient oral intake ti)
prevent or remove a PEG tube, vv iih its attendant difficul-
ties of retlux aspiration and complications associated with
infections. The ultimate goal should be restoration of nor-
mal swallow.

Current modalities have long treatment times: 2-32
weeks (average 15 weeks) for severe dysphagia using tac-
tile and thermal-tactile stimulation'' and .'^-2^) weeks using
biofeedback.' A 4-lolil increase in pneumonia has been
documented during treatment, compaietl to the post-treat-
ment period. "^ Lengthy treatment of swallow ing disorders
is thus risky and may potentially interfere with treatment
of other medical problems.

Spontaneous improvement in swallowing may occur in
certain acute diseases that cause mikl dysphagia.'- How-
ever, in the L'nited Stales only I'i of patients w ith neu-
rologic disorders and PEGs returned to full oral feeding
after one year, suggesting that spontaneous improvement
is rare for cases of severe dysphagia.'

Electrical stimulation (ES) has been reported as a treat-
ment for dysphagia." '^ Park et al'^ applied electricilv
through a prosthetic device on the soft palate, aiming to
re-educate neural pathways associated with the swallow-
ing rellex. They reported a 5()Vt success rate in improv ing
the swallow of patients already capable of oral feeiling.
Transcutaneous application of electrical current to the neck
with a nerve stimulator has alst) been successful in im-

proving swalliiw luiiciioii. bui has rarely been used, be-
cause of assumed concerns lor safely.'' "'

We report a new treatment for dysphagia, consisting of
transcutaneous ES applied through electrodes placed on
the neck. The purpose of this study was to compare the
effectiv eness of ES to TS in patients w ith dysphagia caused
by stroke, and to assess the safety of the technique. Be-
cause ES is a more direct stimulus than TS to nerves and
muscles associated with swallowing, wc h\pothesi/ed that
ES wcnikl lesull in belter swallow function than TS m
patients vv ith comparable conditions of dysphagia. Wc also
monitored patients after treatment to investigate the long-
term effects of ireatmeni and the poieniial for spontaneous
recovery.

Methods

The study was conducted at Hillcrest Hospital, a 280-
bed acute care hospital in a suburb of Cleveland. Ohio. All
new referrals who met entrv criteria and signed Ihe con-
sent form were enrolled during the stLidv period. The study
period was September 2.v \W}. through Januarv 24, 1993.
The stud) population included both in-patients and out-
patients. Entry criteria included:

• primary diagnosis of stroke

• confirmation of swallowing disorder by modified bar-
ium swallow (MBS)

Exclusion criteria were:

• inability to complete at least 2 consecutive dav s of
therapy

•any behavioral disorder that interfered with adminis-
tration of therapy

• substantial retlux from feeding tube

• dysphagia from drug toxicity

Duration of swallow dysfunction did not limit eligibil-
ity. Written, informed consent, as approved b\ the insti-
tutional rev iew board, was obtained from all patients.

Stroke patients with possible swallowing disorder were
alternately assigned lo one of the 2 treatment groups (TS
or ES) imlependenl of any other information and before
being seen b\ Ihe speech-language pathologist. .After as-
signment, the speech-language pathologist peilormed the
MBS with a radiologist to determine the severity of the
swallowing disorder and to assign a swallow score (see
assessment protocol below ). If it was ciMifirmed ihai the
patient did not meet an\ exclusion criteria, the treatment
regimen was begun. No patients were excluded from the
study because of the severity of dysphagia. After the course
of treatment, another MBS was performed and a final
swallow score assessed.

A.ssessiiu'nt I'nitocol

Each patient's swallow lunclion was evaluated via staii-
dardi/ed MBS."" ' with the addition of follow inn the bolus

Respiratory Cari: • Ma"i 2001 Vol 46 No 5

467

Electrical Sumulation for Swallowing Disorders

inlo the stomach to kIlmHiIv esophageal ivlliix that could
result in aspiration. I'atients swallowed various consisten-
cies of food mixed with harium powder while being ob-
served under tluoroscopy. hood consistencies progressed
troni thick to thin, until aspiration occurred. Penetration
was defined as entry of the bolus into the laryngeal ves-
tibule. Aspiration was defined as passage of barium below
the level of the vocal cords. The results of the MB.S were
interpreted as a swallow score according to the criteria
listed in Table 1.

The swallow score was assigned as follows. The speech
therapist would perform the MBS and send the videotape
ot the procedure lo a designated radiologist. The radiolo-
gist would then provide a niirrative interpretation of the
tape in terms of what type of liquid could be safely swal-
lowed. That narrative report was sent back to the speech
therapist, who then assigned the corresponding score (Ta-
ble 1 ). There were 3 radiologists who assigned scores, and
at the time of scoring they did not know which treatment
a patient had received.

The MBS procedure we used was standard except for 2
items. First, instead of barium paste, we used barium pow-
der, because it has less effect on the consistency and taste
of the liquid it is mixed with. The idea is to create mixtures
of different, realistic consistencies but with as much of the
original taste as possible. Paste has a greater tendency to

Table 1. Swallow Funclion Scoring System*

Swallow

Function

Score

Safe Liquid Consistency

Clinical
Implication

Level of
Swallow
Deficit

Nothing safe (aspirates

No solid or

Profound

saliva)

liquid is safe

Saliva

Same as above
(candidate
for PEG)

Profound

Pudding, paste, ice slush

—

Substantial

Honey consistency (liquid
with thickener or
premixed product like
Resource brand liquid
nourishment)

Moderate

Nectar consistency (pureed
fruit juice such as
apricot, peach, pear)

Mild

Thin liquids (eg. cream

No coffee, tea.

Minimal

soups, orange juice.

thin juice

carbonated beverage)

(eg. apple),
or water

Water

All liquids
tolerated

Normal

"This system idenufics the conMMcncy of liquid thai the paticnl can swallow without
aspiration.

ihickcii the mixtuic than powder and also has a more ob-
jectionable taste. The second difference was in the order of
consistencies presented to the patient. Standard references
suggest using thin liquid (eg, water), then pudding, and
then cookie."* The problem with this order is that thin
liquids may be (but are not always) the most easily aspi-
rated."* Thus, if the patient aspirates early in the procedure
because thin liquid was used first, then (a) the airway
becomes contaminated with barium, making \isuali/ation
of aspiration for other substances dilficull. and lb) because
of the aspiration, the procedure may be terminated without
determining what consistency can be safely swallowed.

During treatment, the speech-language pathologist aus-
cultated the right main bronchus during inspiration. A nor-
mal swallow was a single or polysyllabic sound of 1-2
seconds duration, representing the movement of food
through the pharyngeal area and into the esophagus, and
consisted of only clear breath sounds.''' This technique
enabled the therapist to identify abnormal swallowing or
so-called silent aspiration by airway sounds, including rales
and rhonchi, during post-swallow inspiration. Silent aspi-
ration is a condition in which food or liquid enters the
airway but does not produce any obvious signs of aspira-
tion (ie, there is no cough during or after the swallow). -«
The use of auscultation of the right bronchus during in-
spiration and following ingestion of the food or liquid
bolus aided in hearing changes in lung sounds and changes
in the rate of respiration, which often trigger concern about
silent aspiration and justify an MBS. Swallow function (by
auscultation) was assessed each day of treatment protocol
to check for silent aspiration.

Treatment Protocols

General Treatment Protocol. In-patient treatment (either
ES or TS) began within 24 hours of initial evaluation.
Duration was 1 hour per day of treatment and 10 minutes
of challenge/assessment. If a patient became fatigued, treat-
ment wa-s continued later in the day, as often as necessary,
to obtain the full hour. Treatment continued on consecu-
tive days until a swallow function .score of at least 5 was
achieved or the patient was discharged because of insur-
ance constraints. Those patients discharged before achiev-
ing a score of 5 avoided a PEG if they could achieve a
score of at least 2 on consistency of liquid.

Out-patients were treated .^ times per week for 1 hour
per treatment. Treatment continued until they achieved a
swallow score of 6 or it w as judged that no more progress
would be made.

Follow-up on patients was based on medical records
(for readmission) or consultation with the patient, family,
physician, or nursing home therapists, for up to 3 years.

468

Respirator^- Care • Ma'i- 20(^1 Vol 46 No 5

Electricai Si inula I ion for Swallowing Disordlrs

Digastric

Hyoid
Bone

Thyrohyoid

Sternocleidomastoid

Fig. 1 . Diagram of the throat showing placements for pairs of snap
electrodes. One of two placements was used: (A) On either side of
the midline, above the lesser horns of the hyoid bone, on the
digastric muscle. (B) On either side of the midline (preferably on
right side) with upper electrode above lesser horns of the hyoid
bone, on the digastric muscle, and lower electrode on the thyro-
hyoid muscle at the level of the top of the chcothyroid cartilage.
Position A was used for patients with tracheostomies or those
whose anatomy prevented using the other position. Position B
was used for everyone else.

gest conlraclion was observed during the swallow response.
NcunnmisLular F.S consisted of ;i symmetric rectangular
aliernaiing current passing between positive and negative
snap skin electrodes. Frequency and pulse width were fixed

at 80 H/ and .^00 microscconiK. Current intensity was set
to the paticnl's lolciancc and (.'(imlort level. Tolerance and
coinliMi dilTcivd am(in;j iiulniduaK. The .sensation most
patients experienced lirsi was a very slight tingling or
crawling sensation. .As the intensity was increased (in 2.5
mA increments from a start of 2.5 mA up to a maximum
of 25.0 mAi. the individual perceived a strong vibration or
the sensalion that the electrodes were coming loose from
the neck. Most indniduals accommodated rapidly enough
to the sensations that the intensity could be continuously
increased until contractions were consistently audible (des-
ignated the therapy current level). When ES was success-
ful in obtaining a \i)luntary swallow response, the patient
was asked to attempt a sv\allow v\ith a specific oral con-
sistency. ES was delivered at the therapy current tor a total
of 60 minutes per treatment, in the continuous mode, with
a 1.0 second pause between each minute.

All patients were monitored continuously by electrocar-
diography and pulse oximetry. A pulse oximetry-measured
blood oxygen saturation (Sp(, ) decrease of more than 2%
was considered a desaturation due to aspiration. Laryngo-
spasm was defined as a spasmodic closure of the glottis
with severely limited ability to ventilate. Laryngospasm
was judged by the speech therapist, during treatment, based
on audible or \ isible signs of respiratory distress. All re-
cordings were leviewed and interpreted by the medical
chief oi' stall ot the acute care facility.

Data Analysis

Thermal-Tactile Stimulation Treatment Protocol. TS

was gi\en in three 20-minute intervals daily. A speech
pathologist (one of the authors. MLF) used the standard
methodology** for TS. including \erbal coaching. TS was
applied with a size 00 oral examination mirror cooled by
immersion in ice. The base of the anterior faucial arch w as
lightly touched with the mirror back. The mirror was re-
moved, and the patient was asked to close his or her mouth
and attempt to swallow saliva (dry swallow). TS and ver-
bal coaching continued. If a dry swallow was elicited, the
patient vsas challenged with thickened liquids (pudding
viscosity).

Electrical Stimulation Treatment Protocol. ES was

administered by a physical therapist in conjunction w ith a
speech pathologist (MLF). using a modified hand-held bat-
tery-powered electrical stimulator (Staodyn EMS +2. Stao-
dyn Inc. l.ongmont. Colorado). Electrodes were placed on
the neck in one of two positions (Fig. 1 ) and were repo-
sitioned until muscle fasciculations occurred or the stron-

Unpaired / tests were used to compare the mean ages
and the total number of treatments in the two groups. The
Fisher exact test was used to compare the proportions of
females to males in each group. The similarity of co-
morbid conditions was esaluaied v\iih Kendall's tau test
(ie. if a high proportion of TS patients have a co-morbid
condition, do a high proportion of ES patients also ha\e
the co-morbid condition, and vice \ersa). The prt)portions
of confounding factors (ie, brainstem vs hemispheric vs
multiple strokes) in the 2 groups were compared with the
chi-square test. The Mann-Whitney L' test was used to
compare the initial swallow scores (ie, to determine if the
initial degree o\ dysphagia on entering the study was the
same for both groups) and the distributions of final swal-
low scores (ie. to determine itOne treatment group showed
greater impnnement). The change in swallow scores (ie.
initial vs final) was evaluated with the Wilcoxon signed-
rank test. Analyses were performed with StatView soft-
ware (SAS Institute Inc. Cary. North Carolina). Statistical
significance was set at p < 0.05.

Respiratory Care • May 200 1 Vol 46 No 5

469

ELUCTRIC'AL SriMLLAllON lOK SVVALLOVVING UlSOKDLRS

Results

OiiL- Inuulivii l\\ onty-five paliL-nts were screened for pos-
sible inckisiiin in (lie stu(.l\ . Fitieen relLised to sign eunseni
after meeting entr\ criteria, leaving 110 who were en-
rolled. Ninel\-nine patients conipleted the study iTable 2).
All TS patients were in-patients. All hut 6 \IS patients
were in-patients, and one was hotli an in-patient aiul out-
patient. Flc\en patients droppetl out of the study: 6 had
drug to\icit\ Ironi other treatments, 2 were transterred to
other hospitals, and .^ droppeil out lor unrecorded reasons.

The 2 treatment groups were comparable in terms of
mean age and gender distribution and in co-mcMbid con-
ditions that would affect treatment outcome (see Table 2).
The condition that would most negati\ely affect the con-
ventional tieatment group was dementia, and the preva-
lence was identical m the 2 groups. The presence of con-
founding factors related to the t\pe of lesion (ic. brainstem
\s hemispheric stroke vs multiple strokes) was similar in
both groups (Table .'^j. The TS and ES treatment groups
had similar distributions of initial swallow score (p =
0.74). There were aphasic patients in both groups, but
aphasia did not affect their treatment. There were no pa-
tients in the study with apra.xia of swallowing. There were
7 ES \ersus 6 TS patients with dysarthria, but in no case
did dysarthria appear to affect outcome.

Both treatment groups showed improvement in swallow
score (Table 4). However, Figure 2 shows that ES resulted

Table 2. Treatment Groups willi Respect to Demograpliy and Healtli

Table i. Frequencies of Types ol Lesions*

Thermal

Electrical

Variable

Stiinulation
(« = 36)

Stimulation
(n = 63)

Average age

78.1

7.5.7

0.27

Maximum age

101

—

Minimum age

e-s

—

Female (%)

0.83

Co-morhiid conditions*

(%)

.Stroke

Coronar\ arter\ disease

Congestive lieart failure

Chronic obstructive

pulmonary disease

Hypertension

Demenlia

Diabetes mellilus

Parkinson's disease

Cancer

Multiple sclerosis

.morbid condition t ic. pntport

ions were not mutua

•Palicnls iillcii tjad more than one co

lly

exclusive), and proportions were sign

incanlly

corrclalcd by Kcndairs lau (p = n.(X)44l

Treatment

Brainstem Hemispheric Multiple Strokes

Electrical stimulation
Thcrmal-lactilc stimulation

29
19

24
8

•Noi all patients were e\aliiated lor type of lesion. Ttie proportion of otiservations in the
dilferent categories is not significantly different than would tK' expected from random
occurrence (p = 0,18^1

in more people having higher final swallow scores than TS
(p < 0.0001). In addition, all but one of the ES patients
showed some improvement (98%; the one patient remained
at a swallow score of 2), whereas 17 (27%) of TS patients
remained at initial swallow score and 4 (11%) got worse.

ES patients with +6 changes progressed from swallow
function (completely dysphagic) to swallow function 6
(normal swallow). ES patients with +5 changes included
3 patients who progressed from swallow function 1 (tol-
erates sali\a only) to 6. and 6 patients who progressed
from swallow function to swallow function 5. Other step
changes less than +5 include some ES patients who
achieved swallow functions 5 or 6, but these patients started
with swallow function greater than 1. No TS patient, re-
gardless of initial swallow function, achieved a final swal-
low function greater than 4. These results are based on
similar numbers of treatments (average of ."1.3 for ES and
6.0 for TS, p = 0.36).

Several focused comparisons illustrate further differ-
ences between ES and TS. For patients starting at swallow
scores and 1. achieving swallow score 2 or higher indi-
cated successful treatment, in that PEG was not required.
Only 52% {\5 of 29) of TS patients experienced success-
ful treatment, compared to 95% (41 of 43) of ES patients
(p < 0.0001). ES treatments were also more successful
than TS treatments, ba.sed on achievement of complete
swallow score 6 (35% of ES patients vs 0% of TS patients,
p < 0.0002). each starting at swallow score or 1. In
addition. 4 TS patients ( 1 1 % ) required a PEG during treat-
ment. None of the 58 ES patients required a PEG during
treatment, and a swallow score of 2 was achieved within
1-2 treatments in all ES patients.

Twenty-five bedside evaluations performed bv the ther-
apist (ie. auscultation of the right bronchial tree lor evi-

Table 4. Mean Swallow Scores Before and .Mler Treatment

Initial

Final

Trealmoiit

Swallow

Score

Electrical stimulation

llicriiial-tactile stimulation

0.76 ± l.(M

0.75 = 1 .20

4.52 ± 1.69
\.}9 ± 1.13

\ .,ilin.'s iia- ^ slaiidaril de\ialion.

470

Respikaiouv Cari; • Ma'i 2001 Voi 46 No 5

Electrkai Stimulation for Swallowing Disorders

Electrical Stimulation

100

(Sll

12 3 4 5

Initial Swallow Score

100

tfl

12 3 4

Final Swallow Score

100

fin

Thermal-Tactile Stimulation

^ ^ ^ ^

2 3 4 5

Initial Swallow Score

100

«> 80

I ^°

"5 50
40
30
20
10

2 3 4 5

Final Swallow Score

Fig. 2. Distributions of initial and final swallow scores for electrical stimulation and thermal-tactile stimulation treatment groups. A higlier
score means better swallow function. Initial swallow scores for the two groups were similar (p = 0.74). Both groups showed improvement
in score (thermal-tactile stimulation p = 0.0048; electrical stimulation p ■; 0.0001). The electncal stimulation group had higher final scores
(p < 0.0001).

dence of rhonchi dp change in ventilatory pattern) were
compared with corresponding MBS studies interpreted by
a radiologist. Only one of the 25 comparisons disagreed:
the therapist judged silent aspiration that was not con-
firmed by MBS. This yields the decision matrix shown in

Table 5. Analysis of ."Xgreemcnt between Bedside Assessment of

Silent Aspiration and Results of Modified Barium Swallow

Table 6. Proportions of Patients in Post-Treatment Categories

MBS

Interpretation

Bedside Evaluation

Aspiration
Present

Aspiration
Absent

Aspiration present
Aspiration absent

uallou

MBS - ni(Klificd harium

Thermal

Electrical

Category

Stimulation

(n = 33)

(n = 52)

No change for >2 y. alive

0.061

0.289

No change for <2 y, lost*

0.242

0.269

No change for <2 y, died*

0.364

0.250

Improved within 2 y

0.000

0.077t

Aspiration or PEG

0.242

0.000

New episode of dysphagias

—

0.115

Received ES after TSi

0.091

—

•Average lime of follow-up >I year.

tProponion i-. 0,143 of 28 electrical siimulaiion paiienis with final swallow funciion < 6.

PEG = percutaneous cnicroslomal gastric luhc

ES = electrical stimulation

TS = thermal-tactile stimulation

tFuU swullow funciion rcsloa'd alter electncal sliniuhilion

Respiratory Carl • May 2001 Vol 46 No 5

471

Electrical Stimlilaiion iok Swali.owinci Disorolks

T;ihlc 5, The positive pivdiLli\L- \;ihic \\;is 24/25 = 96%;
the true positive rate was 24/24 = KID'' ; the false positive
rale was 1/25 = V/r.

l-'ollow-up data sho\\ ihal Ihc cITeets of Irealnienls ad-
ministered diiriiiii tlie stiidv generalls |iersisted (lahle ft).
Most patients retained their final svvallovs lunetion for over
2 years (89% for ES and 67% for TS). Loss of swallow
function during the post-treainient period for FS patients
was based on new episodes of the problems that caused the
dysphagia. None of Ihc TS patients showed improved swal-
low function, whereas 4 ( 14',^ ) of ES patients improved (3
confirmed by MBS). There was a high rale ol' aspiration
(24%) in TS patients, compared with no aspiration in ES
patients. Two of the aspirating TS patients received a PEG.

A total of 31S applications of ES were administered to
patients during this study. Not a single case of laryngo-
spasm or decrease in S|,,, was observed. No change in
heart rhythm occurred, based on electrocardiograph rhythm
strip recordings.

Discussion

The demographic similarities between the two groups
(Table 2) indicate ihat the desired properties of random-
ization from the same underlying population were in fact
achieved for the two treatment groups, despite the fact that
a strict randomi/ation scheme was not used.-' There was.
however, one general difference between the two groups:
the ES group was treated much longer after stroke than the
TS group. This is because most of these patients had al-
ready failed conventional therapy, which was the reason
they were referred for the study. The longer the period
after the stroke, the less success is expected vv ith dyspha-
gia treatment. Despite this potential bias against the ES
treatment, the ES group showed better results than the TS
group.

Bedside evaluations are important in determining the
safety of treatment, to estimate the patient's progiess dur-
ing the treatment period, and to juslity further MBS stud-
ies. In our study, auscultation was used to detect silent
aspiration during treatment. The abilitv to detect aspiraiion
b\ this method was evaluated by comparison with radio-
graphic evidence of aspiraiion. However. MBS procedures
were done only for patients w ho were suspected of aspi-
ration (silent or not). Therefore, we collected no data from
which negative predictive value could be estimated, yet
the high positive predictive value suggests that ausculta-
tion deserves further study as a potenlially useful screen-
ing test for silent aspiration. More research should be ilone
to identify the optimum bedside evaluation technique and
to compare its accuracy with the gold siaiulard. MBS.

Application of ES to muscles associated with swallow-
ing links swallowing therapy with physical therapv. A
fundamental principle i)f physical therapy is that disuse of

a siriaieil muscle leads to alrophv of thai muscle, even if
the medical condition leailing to disuse has no diiect effect
on the muscle or associated nerves.-- Loss of muscle tone
is identified bv physical therapists as little or no measur-
able contraclililv or strength. When attempts at exercise
alone fail to result in contraction of an atrophied muscle,
ES may enhance tone to the |ioint where exercise may
strengthen or activate the muscle.

There may be an analogy with dysphagia. A medical
event such as stroke may block the primary neiual path-
way for swallowing. There are fewer myofibrils per motor
unit of the laryngeal muscles relative to larger muscles
(4-6 vs 4. ()()()). and there are numerous small muscles of
this type that participate in the oropharv ngeal phase of
swallow.-' In addition, the motor units within each laryn-
geal mirscle tend to fire asynchronously during a normal
swallow, contrasting with the more synchronous tiring of
larger muscles designed for strength.-' Under this model.
even a few days without the tvpical 6()()-2.4()() normal
swallows per day--* -^ could lead to long-term dysphagia.
Though this design of small muscles might make them
more susceptible to failure from lack of use. it is possible
that this design can respond more fully to ES. Perhaps this
is a reason why ES ol the neck restores effective swallow
with fewer treatments than required for restoration of ap-
propriate function by ES of other muscles of the body.-''
Alternatively, fewer treatments might be associated with
stimulating a retlex, since swallowing is a complex action
that is usually initiated voluntarily but is always completed
as a rellex inv olv ing afferent and efferent cranial nerv es-" -"
and primary and secondary swallow centers in the cor-
tex.-'' These muscle tone and reflex hypotheses also per-
tain to the success of ES in treating urinarv incontinence.'"
Much research is required to determine whether ES. ap-
plied at a sensory level in our stud\ . w orks \ ia a peripheral
nerve, a direct effect on the small muscles, the central
nervous system, or a combination of these factors.

Our data directly address issues of safety. ES of the
head and neck, discussed in the recent third edition of
Charles Darwin's '/'/;(' Expression nf ihc Enunions in Man
and Animals.'^ has been the subject of majt>r recent debate
about safety. Possible risks include arrhvthmia. hypiUen-
sion, interference wiih pacemakei. laryngospasm. glottic
closure, burns, and tumor growth.-^ However, one suc-
cessful studv that applied external ES to a nerve of the
neck had no complications."' Other studies also observed
no change in vital signs, electrocardiograph, or other ad-
verse effects in patients who received implantable recur-
rent larvngeal and vagal nerve stimulators used to treat
spastic dvsphonia or control epilepsy.-'' -" External appli-
cation of ES with a muscle stimulator within the settings
used in our study appears safe, at the sensory level of
application. Standard electrode placement in our studv pur-
posely avoids the carotid body. In addition, the voltage

472

RE.SPIRATORY Carl • M x^ 2001 Voi 46 No 5

Elecirical Stimi'i aiion iok Swallowing Disorders

and current used in our device are linver than is delivered
by a standard neuriinuiseular stimulator, assumed h\ other
authors concerned o\er the safety of ES.

The most important theorelical risk ot" ES is iaryngo-
spasm. In an animal studs, laryngospasm was achieved
with repetitive suprathreshold E.S. hut not uiili single-
shock excitation of the superior laryngeal nerve.-' As stim-
ulus frequency went above .^2-64 H/. there was a de-
crease in adductor after-discharge and glottic pressure.-**
In our study, suprathreshold levels of stimulation of the
superior larvngeal nerve did not occur, because of the level
of therapeutic current, limits on the maximum current of
the stimulator, and attenuation by soft tissues of the neck.
The higli-frei|uencv stimulation of ES for dysphagia ex-
ceeded (i4 H/ and may he one of the factors protecting
against laryngospasm. In addition, the constant cinivnl stim-
ulator automaticalK dropped the voltage to maintain a
constant cinrent dose in the event of decreased electrode
or tissue resisiance. \\ ith these safeguards, a device as
configured for our siudv is apparenllv safe. The hypothet-
ical concerns about safety are not supported by our data.

Although there are reports in the literature that stroke
patients can recover their swallow spontaneously.'- tube
feedings were needed for l.'i-6() vveeks.^" '" Howard et al'
indicated that 30% of all patients ce)ntinued on total tube
feeding at one year after stroke. The patients w ho received
ES in our study began eating following 3 treatments and
did not require tube feeding thereafter. ES may initiate
muscle reeducation prior to the beginning of spontaneous
recovery and prevent the need for tube feeding.

In an age when extensive efforts are made to reduce
health care costs, the ES protocol can contribute substan-
tially to those efforts. Between 300.()()() and 600.()()() new
cases of dysphagia occur each year in stroke patients.-' In
1992, the cost of United States enteral nutrition in neuro-
logic disease alone exceeded 330 million dollars per year.'
Since the ES protocol restored sw allow function to a score
of 2 within 1-2 days of treatment, a hospitalized stroke
patient who lost swallow function in association with the
undcrly ing medical problem ciuild cat on his or her own or
with reduced assistance as an in-patient. Six ircatmcnis of
one hour each day. for in-patients or out-patients, would
be expected to restore normal swallow in 35** oi the most
severe cases of stroke and 459^ of all stroke cases. The
medical implications for patients include reduced amounts
of therap) (fewer sessions, less traveling), avoidance of
surgery for PEG (and attendant coiiiplicaiions). avoiilance
of specialized dietarv regimens, normal liquid intake, and
reduced risk o\ aspiration pneumonia. Caregivers benefit
from increased efficiency. Corrected dysphagia wduki in-
terfere less with treatments for other medical problems
while improving cost effectiveness for health care facili-
ties. The social implication ol lower medical bills and less

restricted social activities associated with eating is higher
quality of life for both the patient and the family.

A potential limitation of this study is that, though the
scoring of swallow function was fairlv objective (sec Ta-
ble I ). it does not preclude subjective bias. However, we
compared the distribution of final swallow scores of 29 TS
patients from our study with that of .53 patients treated
with IS by Neumann et aP and found no difference (Kol-
mogorov-Smirnoff test KS = 0.2531. p = 0.13). There-
fore the difference between TS and ES was probably not
due to bias against TS. The physical evidence of .MBS
reveals nii bias in favor of ES. In addition, the swallow
function score we used is no more subjective than the
score validated and published by Rosenbek et al.-"^ The
major difference with our score is that we did not record
the trajectory of the bolus, but only whether it was aspi-
rated and the consistency of liquid aspirated. Because con-
sistency affects risk of aspiration, the purpose of the score
is to rank the consistency of liquid that can be safely
swallowed. This is the type of information referring phy-
sicians prefer to see as an interpretation of the MBS pro-
cedure because it helps them formulate instructions for the
patient.

Conclusions

Transcutaneous ES appears to be a safe and effective
treatment for dysphagia caused by stroke, and it results in
better improvement in swallow function than does ther-
mal-tactile stimulation. Normal swallow lunction was re-
stored to 35% of the most severely dysphagic patients in
less than a week of daily treatment, to 45% of patients at
all levels of severity, and the restoration persisted until a
new episode of dysphagia occurred. The onlv limitations
of ES arc that it cannot be done on patients who talk
continuously (such as is found in some severely demented
patients), patients who have beards must be willing to
shav e them for ES. and TS treatment requires the patient's
cooperation in opening the mouth and in liillow ing verbal
commands.

\( KNOWI inCMF.NTS

The authors wish lo ackiHiulcJ;;!.- ihc mmriliutions of Marie .Vsmar PT.
F.rol Bestas MD. Roberl F. Boiti MD. RcticccaCann PhD. Kennclh Hawk
PT. Bernard Kollon MD. Nanc\ l.ynam Davis, Joan Rotlienbcrg MD.
and Howard Tucker MD.

REFERENCES

L Bello J. editor. Prevalence of speech, voice, and language disorders
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2. Gordon C. Hewer RL. Wade DT. Dysphagia in acute stroke BMJ
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3 Howard L, Anicm M. Mcining C'K. Shiko M, Sleigcr E. Current
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4. Hogue CW, Lappas GD. Creswell LL. Lerguson IB. Sample M.
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llO(2):517-522.

5. Neumann S, Bartolome G. Buchholz D, Prosiegel M. Swallow-
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treatment variables and therapeutic methods. Dysphagia 1995:101 1 ):
1-5.

6. Langmore S, Miller RM. Behavioral iicalnicnt for adults with oro-
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1159.

7. Logemann J. Evaluation and treatment of swallowing disorders. San
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8. Lazzarra G, Lazarus C, Logemann JA. Impact of tliennal stimulation on
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9. Crary MA. A direct intervention program for chronic neurogenic dys-
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10. Rosenbeck JC. Robbins J, Fishback B. Levine RL. Effects of thermal
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11. Singh V. Brockbank MJ, Frost RA. Tyler S. Multidisciplinary man-
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13. Freed M. Christian MO. Beytas EM. Tucker H, Kotton B. Electrical
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15. Park CL. O'Neill PA. Martin DF. A pilot exploratory study of oral
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17. Ott DJ, Pikna LA. Clinical and videofluoroscopic evaluation of swal-
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IS. Logemann JA. Evaluation and treatment of swallowing disorders.
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19. Leonard R. Kendall K, editors. Dysphagic assessment and treatment
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20. Carrau RL, Murray T. Comprehensive management of swallowing
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25. Rosenbek JC. Robbins JA. Roecker EB, Coyle JL, Wood JL. A
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26. McQuain MT, Sinaki M, Shibley LD, Wahner HW, llstrup DM.
Effect of electrical stimulation on luinbar paraspinal muscles. Spine
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27. Friedman M, Wernicke JF, Caldarelli DD, Safety and tolerability of
the implantable recurrent laryngeal nerve stimulator. Laryngoscope
1994:104(10):1240-1244.

28. Sasaki CT, Suzuki M. Laryngeal spasm: a neurophysiologic redefi-
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29. Hamdy S. Aziz Q, Rothwell JC, Singh KD, Barlow J. Hughes DG.
el al. The cortical topography of human swallowing musculature in
health and disea.se. Nat Med 1996;2(1 1):1217-1224.

30. Fall M, Lindstrom S. Electrical stimulation: a physiologic approach
to the treatment of urinary incontinence. Urol Clin North Am 1991;
18(2):393-407.

31 . Darwin C. The expression of the emotions in man and animals, 3rd
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474

Ri si'iKAiDRY Carl • Ma') 2001 Vol 46 No 5

Special Articles

Partnering for Optimal Respiratory Home Care:

Physicians Working willi Respiratory Therapists

to Optimally Meet Respiratory Home Care Needs

Greg Spratt RRT CPFT and Thomas L Petty MD FAARC

Introduction

\Mi:it Is till' Nicd lor Rcsi)ir;itor\ Home (are?

Conditions Ki-qiiirin^ Kcspiratorx Homi' Care

Influences on the Need for Kespiratorv Home Care
How Is Optimal Respiratory Home Care Delivered?

Team Approach

Respiratory Therapists in the Home

Henellts of Respiratory Home Care
How Does Reimbursement Affect the Qualit\ of Care?

Influence of F^quipment Reimbursement Methods on Quality of Care

Kffect of Recent Cuts
Discussion
Summary

The need for respiratory care services continues to increase, reimbursement for those services has
decreased, and cost-containment measures have increased the frequency of home health care.
Respirator) therapists are well qualified to pro\ide home respirator) care, reduce misallocation of
respirator) ser\ices. assess patient respirator) status, identify problems and needs. e\aluate the
efTect of the home setting, educate the patient on proper equipment use, monitor patient response
to and complications of therap). monitor equipment functioning;, monitor for appropriate infectitm
control procedures, make recommendations for changes to therap) regimen, and adjust therapy
under the direction of the physician. Teamwork benefits all parties and offers cost and time savings,
improved data collection and communication, higher job satisfaction, and better patient monitor-
ing, education, and (pialit) of life. Respirator) tiierapists are positioned to optimize treatment
efficacy, maximize patient compliance, and minimize hospitalizations among patients receiving
respirator) home care. Key words: rcspinnary home care, respiniiorx iherapisi. reinilnirseiiieni. cillo-
caiion. IRcspn C'uiL- 2001 ;46(5):475-488J

Introduction

The American Association tor Respiratory Care ( AARC)
has defined ""respiratory home care"" as

Greg Spralt RRT CPFT is affiliated vs ith RoTech Medical Corporation of
Orlando. Florida. Thomas L Petty MD FAARC is alTiliated with the
Department of Medicine. Univcr.ity of Colorado Health Sciences Center,
Denver. Colorado, and with St Luke's Medical Center. Chicago. Illinois,
and with the National Lung Health Education Program. Denver. Colo-
rado.

. . . those loriiis of respirator) care pro\ idcd in the
patient's place of residence by personnel trained in
respiratory care working under medical supervision.
The goals of respiratory home care arc to improve
the patient's physical well being and potential for
productivity, and to protnoie self-sufficiency within
the individual's limitations.'

Correspondence: Greg Spratt RRT CPFT. RoTech Medical Corporation.
PO Box 747. Kirksville MO (i.^.SDI. E-mail: gspratt@rotech.com.

Respiratory Care • Ma^ 200 1 Vol 46 No 5

475

Partnering for Optimal Respiratory Home Care

Respirators scr\iLCs comiminly pro\ idcd to the home
setting include: equipment, accessories, and supplies used
for therapeutic interventions; assessment, diagnostic, and
monitoring procedures: and respiratory therapists (RTs) to
provide patient education, rehabilitation services, disease
and case management, and to conduct research (Tabic 1 ).

RTs ha\e been recognized by many physician organi-
zations as the most appropriate ancillary health care per-
sonnel to provide home respiratory services.--^ The Na-
tional Association for the Medical Direction of Respiratory
Care (NAMDRC) statement reads, "NAMDRC unequiv-
ocally supports the premise that RTs are the nonphysician
care givers who are best qualified by both education and
examination to render respiratory care services in the hos-
pital and alternate sites, including the home."-'' The Cali-
fornia Thoracic Society states, "The RCP (respiratory care
practitioner) is qualified to assist the physician in assess-
ing the overall needs of patients, and recommending and
delivering necessary care."''

What Is the Need for Respiratory Home Care?
Conditions Requiring Respiratory Home Care

An estimated 20% of patients over age 65 have func-
tional impairments with related home care needs that are
often unrecognized during the typical office visit.* Dis-
eases requiring the provision of quality home respiratory
services are on the increase. Chronic obstructive pulmo-
nary disease (COPD) is currently the fourth leading cause
of death in the United States, and its incidence has in-
creased 41.5% since 1982. Sixteen million Americans with
COPD have been identified, and it is estimated that 30-35
million Americans may be afflicted. COPD is the only
major cause of death in which the numbers are rising.
While mortality from heart disease (number one cause of
death) decreased 45% and cardiovascular disease mortal-
ity (number two cause) decreased 58%, mortality from
COPD increased 32.9% from 1979 to 1991. Direct co.sts
for the care of COPD are estimated at $7-15 billion an-
nually.^ In 1998, the National Heart, Lung, and Blood
Institute placed the total annual cost of COPD in America
at $26 billion.'* Some are predicting that unless current
trends are reversed, COPD is likely to be the biggest health
problem of the new millennium." At least two major ef-
forts are directed at addressing these growing trends. The
National Lung Health Education Program is a national
effort endorsed by several major physician organizations,
the AARC, and the National Heart Lung and Blood Insti-
tute. An international effort, the Global Obstructne Lung
Disease Initiative has been founded by the World Health
Organization to explore this problem from an international
perspective.

Asthma, another disease frequently requiring respira-
tory home care, presents a similar picture. Asthma affects
14-15 million Americans, and the incidence of asthma is
also increasing.'" It is the most cominon chronic disease of

Table 1. Respiratory Services Currenlly Provided in the Home
Setting

Therapeulie

Aerosol therapy
Bland aerosol
Hand-held (jel) nebulizer
Ultrasonic nebulizer
Continuous aerosol
Croup tents
Inhaled medications

Beta adrenergic agonists
.Anticholinergics
Mediator blocking agents
Stcioids
Pentamidine
Other medications
Oxygen therapy

High pressure cylinders
Oxygen concentrators
Liquid oxygen
Transtracheal oxygen
Portable oxygen
Portable liquid

Portable high-pressure cylinders
Oxygen conservation devices
Ventilation

Invasive positive pressure ventilation
Noninvasive positive pressure ventilation
Negative pressure ventilation

Abdominal belts, rocking beds, and other hybrid ventilation devices
Lung expansion therapy
Incentive spirometry
Intermittent positive pressure breathing
Metered-dose inhalers and chambers/spacers
Diagnostics and monitoring
Spirometry
Peak flow
Oximetry recording
Sleep studies/polysomnography
End-tidal carbon dioxide/capnography
Cardiac event monitors

Infant cardiopulmonary monitors/event recorders
Patient and home assessment
Physical assessment
Home environmental assessment
Response to therapy
Patient education
Rehabilitation services

Activity/exercise programs
Disease/case management
Research

476

Respiratory Care • May 2001 Vol 46 No 5

Partnering for Optimal Respiratory Homi: Cari;

childhood, affecting 7.4% of children ages 5-14 years ami

4.8 million children under 18 years of age. Asthma pre\-
alence in prcschiH>l children was estimated at 5.8'^ of
children under age 5 in 1994 (as reported by a family
member), a IWK! increase since 1980." In 1994, 5.4% of
Americans reported ha\ inj: asthma, a 15'7c increase since
1980. There are more than 5,000 asthma deaths'- ami
470.000 asthma hospitaii/ations annually, and there were

1.9 million cmcrgcncN room \isits for asthma in 1995.
Health care ccsts are estimated at more than $6 billion
annually," with another SI billion in lost productivity.
Asthma resulted in 100 million da\s of restricted acti\ity
and more than 10 million missed school days.'-*

Sleep apnea and pneumonias associated with human
immunodeficiency \irus/acquired immunodetlciencN syn-
drome are also on the increase.'^" Other cardiopulmo-
nary disea.ses such as congestive heart failure, stroke, and
lung cancer frequently require home respiratory services.
Even patients with nonpulmonary diagnoses may require
home respiratory services. This is especially true in neu-
romuscular diseases such as motor neuron disease, mus-
cular dystrophy/atrophy, spinal cord injury, myasthenia
gravis, and diaphragmatic paralysis, in which respiratory-
insufficiency or failure can pla> an important role and is
often the cause of death.

Influences on the Need for Respiratory Home Care

The American Medical Association's Medical Manage-
ment of the Home Core Patient: Guidelines for Physicians
states, "home care should be the 'first option' — preferred
over hospitals, emergency departments, or nursing homes,
whenever care needs can be safely met at home.""* Several
current trends and factors are present in the health care
sy.stem that will influence the need for home respiratory
services. These trends are all likely to increase the need for
quality home services in the future.

Changes in Reimbursement. Changes in reimburse-
ment will continue to affect the provision of respiratory
home care. Managed care organizations, as well as Medi-
care and Medicaid, will continue to explore ways to sta-
bilize or decrease costs while maintaining or improving
outcomes. The home setting has pro\en to be a less costly
setting for care than acute, subacute, and long-term care
centers."--- A wide variety of respiratory services can be
safely delivered in the home. Many procedures currently
delivered at higher levels of care are likely to move to the
home. Pilot programs to provide home sleep studies. 2'
pulmonary rehabilitation. -■*-" and exacerbation manage-
ment-'* "' have demonstrated equivalent or better results at
lower costs than hospital-based programs. Effective home
care programs can even reduce the need for hospitali/a-
tions.29-32

Decreasing \\uilul)ill(y of llonie Health. With changes
to the rcimhursement structure ol home health services,
access to intermittent skilled visits by nurses, physical
therapists, or occupational therapists has decrea.sed. It has
become increasingly difficult for patients to qualify for
coverage of home health visits. A recent George Wash-
ington L'niversity study showed that 68% of hospital dis-
charge planners report increased difficulty in initially ob-
taining ht)me health services for Medicare beneficiaries.-"
As a result of reimbursement cuts from the Balanced Bud-
get Act of 1997. nearly 2.500 Medicare-certified home
health agencies have closed nationwide and 5(X),00(J fewer
beneficiaries were served in 1998 than 1997.''' Many pa-
tients with home needs may not qualify under the current
guidelines or the physician may forego home health ser-
vices for fear of accusations of abuse or simple ignorance
of the coverage guidelines.

Patient Preferences. Patients prefer to receive care in
the comfort and safety of their own homes. ^"^ Provision of
care in the home reduces exposure to infectious agents and
allows for better rest. It has been demonstrated that quality
of life is directly related to the patient's ability to remain
at home and avoid the need for institutional care.''^

Graying of the "Baby Boomers." In 1987. 12.2% of
the population was age 65 years or older. By the year 2030
this percentage will increase to 25%. There are currently
35 million Americans age 65 years or older. Conditions
more likely to occur in the elderly, such as COPD. are
likely to increase as the population increases. With this,
the need for quality respirator) home care will also in-
crease."'*^

"Treatment to Prevention" Paradigm Shift. The train-
ing and skills of RTs ha\e positioned them to take advan-
tage of a paradigm shift in medicine, from treatment of
disease to prevention of disease.'** Spirometry has been
demonstrated to predict debilitating lung disease decades
in advance of the onset of symptoms, allowing an oppor-
tunity for aggressive intervention. An accelerated rate of
decline not only predicts predisposition toward lung dis-
ease, but also heart disea.se,-'^-*- stroke.-*' lung cancer.-"--*'
cancers of all types, and premature mortality in general.-**
RTs are the personnel best trained to assist physicians in
performing spirometry and other respiratory assess-
ment. ■'^•■'•'* They are also able to pro\ide early intervention
in the form of smoking cessation and other therapeutic
options (eg. inhaled medications), and it is possible to
deliver many of these interventions safely and cost-effec-
tively in the home setting. '*■'■-''' '-

Disease and Case Management. Though efforts at dis-
ease pre\cntion will increase, chronic illness will continue

Respiratory Care • May 2001 Voi. 46 No 5

477

PaKINKRING for OpTIMAI Ri SIMKAIOKV HOME CaRE

lo be a primal \ coiK'crn willim iIk- hcallh care sssIlmh.
()\ci' halldl iIk- maiKiiiL-d caiv dullars spc'iil in the United
Slates go toward treatment ol the sickest 5'/< of patients
and over 7()'i is directed to the sickest KK/r ol' patients.^'"

w^ . . I . ,_.,.- ,. 1 ; ...u;i.^ ;.-.-.

Programs tl

lat can licmoiistrale cost reductions while im-
piinint; patient outcomes will be attractive to managed
care pro\ iders, oilier insurers, employers, and patients, who
all share in the cost olcarc. These programs have already
ilemonstrated elTicacv in ilisease stales such as asthma and

A major goal ol such programs is to manage the patient
in the least costh setting in which care can be safely and
effectively administered, which is often the home.'" "

Karlier Dismissals from Acute Care. One of the em-
phases of managed care and Medicare's Diagnosiieally-
Related Groups (DRG) system in controlling costs is the
elimination of lengthy (and costly) hospitalizations. Under
the previous "fee for service" arrangement, there was a
financial incentive to keep patients in the hospital for as
long as it took or until they were completely recovered.
Now the goal is to manage the initial, most severe stage of
ihc illness in the acute setting and to transfer the patient to
a lower (and less costly) level of care as rapidly as possible
without compromising outcomes or patient safety. This
has translated into patients going home "quicker and sick-
er." which increases the need for quality home care to
manage the more acutely ill home patient.^" Cotton et aP"
found that a program of early discharge followed by home
visits was as effective in preventing deaths and readmis-
sions as is traditional in-patient management for uncom-
plicated exacerbations of COPD.

Advancing Technology. Advances in technology will
cimtinue lo facilitate the move of care to the home. The
cost of health care technologies continues to decrease,
making them more accessible. Diagnostics and therapeu-
tics once only available in the hospital setting are now
routineh available in the liome. Spirometers that fit in a
pocket are a\ ailable to pro\ ide accurate results, printouts,
and even interpretation iif results. Oximeters not much
larger than the linger ilscll can provide insianl readouts ot
oxygenation. The ongoing Sleep Heart Health Study has
demonstrated that home polysomnography is a viable al-
ternative to hospital-based studies.""

Telemedicine is certain to affect the home setting as
well. It is not unreasonable to picture a scenario where a
homebound patient is assessed and managed hv the pin-
sician via monitoring transmitted over telephone lines or
other modes of electronic transfer. Transmission of v ideo
signals, electrocardiography data, lung sounds, spirometry
data, sleep data, and other physiologic data is no longer
hypothetical: it is available today. Advancing technology

is certain lo improve the ciiialilv of these data while de-
creasing costs.

These and other factors will conliiuie to make the home
setting more important in the overall caie ot patients re-
quiring respiratory services. Regrcttablv. in the lace ol the
increasing need for quality respiratory home care, there are
substantial changes in reimbursement that threaten to limit
the availability of professionals to prov iile this care.

How Is Optimal Respiratory Home Care Delivered?

Team Approach

As in other specialties, such as pulmonarv rehabilita-
tion, optimal care is achieved by a team effort. This team
includes the patient, the patient's family and/or friends
who are involved in care, the physician, the physician's
staff, and ancillary health care personnel who provide in-
home services (Table 2). Other community services (eg,
"Meals On Wheels" and home aides) may also be required
to make the home environment more conducive to patient
care. For optimal care to occur, it is essential that adet|iiate
support (eg. caregivers) and resources (eg. medical equip-
ment) are available to the patient. Failure to provide this
support is likely to result in the need for placing the patient
in higher, more expensive levels of care (eg. nursing ta-
cilities) or to increase the frequency of hospitaliza-
tion.s"*""

Respiratory Therapists in the Home

RTs are the ancillary health care personnel most likely
to be available for many patients with chronic lung dis-

Table 2. Componenls of the "RespiriUory Home Care Team"

Palienl and caregivers
Patient
Spouse

Other lamiiv memhcrs
Friends/neiiihhors

Physician's olTicc
Physician
Nursing stall
Other clinical staff
Non-clinical staff

.\ncillarv health c.ire professionals and paraprofe.ssionals
Respiratory therapist
Home health mirse
Occupational therapist
Physical therapist
Registered dietitian
Dismissal coordmators
Home aides

478

Rn.spiRATOR>- Carh • May 2001 Voi 46 No 5

Partnering for Optimal Respiratory ]h>\\\ C\\<\

Ciisc. As statcil prc\iously, home health visits by nurses
and physical theia|iists are beini: curtailed by changes in
the reimbursement structure." '•* Because many of these
patients require durable medical ec|uipment (eg. nebuliz-
ers, oxygen, \eniilalorsi. KTs eniplo\etl by home medical
equipment and respiratory therapy (lIMh/KTi providers
perlorm home \isiis to these patients. RTs are emploseil
b\ IIMli/KT ciimpanies because RT expertise is required
tor setting up and maintaining home respiratory equip-
ment. On less complex pieces of equipment (eg. nebuliz-
er), the RT visit may be a one-time e\enl at the set-up.
whereas tor more complex equipment (eg, oxygen, venti-
lators) home visits ma\ be made on a regular and ongoing
basis.

Because the RT is already visiting the patient's home,
there is an opportunity for the RT to function as a support
to the phssician in optimizing the iiome respiratory care
provided. The training, skills, and experience of the RT
can be invaluable to both the patient and the ph\sician in
a number of ways.

Patient Education. Education of the patient, the family,
and other caregivers is an essential element of effective
disease management. RTs are well-equipped to provide
training on lung function, pathophysiology, cardiopulmo-
nary medications, breathing and cough retraining, use and
care of equipment, smoking cessation, recognition of signs
of an exacerbation, the importance of regular activity or
exercise, and other topics pertinent to patient care. ■*''■''-'
Patients who receive education are better equipped to par-
ticipate in their own care (ie. collaborative self-manage-
ment"^) and more likely to remain compliant with the treat-
ment ordered by the physician."' '* Demands on the time
of the physician make it difficult, if not impossible, for the
physician to spend the time required for adequate educa-
tion in these subjects.

Monitoring Response to Therapy. By observing and
assessing the patient on an initial visit or during ongoing
visits, the therapist is able to evaluate the patient's re-
sponse to therapy. For example, if the patient continues to
exhibit symptoms of bronchoconstriclion (eg. wheezing,
coughing, dyspnea) after the implementation of broncho-
dilator therapy, this should be reported to the physician so
that alterations can be made to the bronchodilator therapy,
such as adding additional medications."'' increasing dose
or frequency,"" or changing delivery methods."' Failure to
do so could result in suboptimal management of air How
obstruction, decreased function, the need for additional
hospitalization, and increased total cost of care."'' "'

Recognizing and Responding to Complications and .Ad-
verse Reactions. With most home tliera|iies there is the
potential lor complications or aiiserse reactions. The |ia-

tient or the patient's family ma\ disregard the importance
ot seemmgls benign reactions to therapy as "not important
enough " to call the doctor. Minor complications such as a
dry or sore nose may lead to noncompliance with oxygen
therapy. More serious adverse reactions such as pneumo-
thorax due to positive pressure therapy (eg, ventilation)
may even place the patient's well being at risk. A skilled
therapist will not only recognize the importance of such
problems but can otfer solutions to improve compliance
and reduce risk to the patient.

Equipment Monitoring. It is important that respiratory

equipment be piDjieiiy monitored for safe and effective
operation. Patients typically do not have the ability to do
so on their own because of a lack of knowledge and spe-
cialized equipment necessary to monitor the operation of
the equi|iment (eg, oxygen analyzers, pressure manome-
ters). It is our experience that when oxygen concentrators
go unmonitored they may continue to "run" and give the
perception ol working correctly, but on examination with
an oxygen analyzer it is revealed that they are dispensing
nothing more than room air. This has been demonstrated in
countries where oxygen concentration is monitored less
frequentlv .■'-

Educati(m and Monitoring of Infection Control Proce-
dures. Patients should be educated in proper cleaning
and infection control procedures and then monitored for
compliance. The consequences of inadequate infection con-
trol can be serious. Without proper maintenance, a device
meant to help a patient could actually become the instru-
ment that causes repeated infections, exacerbations, and
even hospitalizations.''-'

Adjusting Therapy Based on Response. Just as in the
acute care setting, it is often desirable to allow the thera-
pist to adjust therapy within phvsician-detlned guidelines
based on patient response. This places the therapist in the
role of the "physician extender" in much the same manner
that therapist-driven protocols do in the acute care setting.
It allows for more appropriate therapy while minimizing
inconvenience to the physician. Having the physician per-
form these procedures would be burdensome and logisti-
cally diflicult. A common example of physicians giving
home RTs this level of responsibility is in adjusting oxy-
gen therapy (eg, titrating How to maintain pulse-oximetry-
measured blood oxygen saturation |S|,^, ] over 90%) and
especialK in noninvasive positive pressure ventilation,
where titration of multiple ventilation variables (eg, in-
spiratory positive airway pressure, end-expiratory positive
airway pressure, fraction of inspired oxygen, backup rate,
rise time, and inspiration-expiration ratio) is commonly
performed in the home by the therapist within established
guidelines.

Respiratory Care • May 2001 Voi. 46 No 5

479

Partnerinc. ior Oi'TiMM Risi'iKAiom Home Caru

Exacerhation Prevention. B\ oiliicaiini; patients and
Ihcir careiiivcrs on the early signs o\' exaeerbation and by
nionitiiring patients on regular \isits for signs and symp-
toms of" deterioration, the RT can help prevent exaeerba-
lions or at least c.|uiekly intervene so as to avoid hospital-
ization. In COPD. exaeerbations are generally linked to
infections or heart lailiire. both ot whieh can be managed
more effectively when recogni/ed and treated in their ear-
liest stages. Early intervention can spell the difference
between managing the patient at home (eg, adding antibi-
otics, a steroid burst, and more aggressive bronchial hy-
giene) or providing the same care in a more costly acute
care setting. ''■'

Environmental As.sessment. The home setting can has e
a dramatic impact on the condition of the respiratory pa-
tient. The effects of a poor home environment may include
exposure to common allergens (eg. dust miles, cockroach
excrement, pet dander, mold), inhaled irritants (eg. to-
bacco smoke, cooking fumes, perfumes, cleaners), lack ot
adequate resources (eg. financial, nutritional), improper
support systems (eg, caregivers), inadequate mechanical
systems (eg, electrical, clean water, air conditioning), dif-
ficult physical circumstances (eg. multiple stairs, unstable
llooring). and even abusive situations (eg. neglect, physi-
cal abuse).

The American Medical Association recognizes the im-
portance of in-home assessment, stating that

For most patients, in-home assessments arc prefer-
able and may be crucial to fully understand a patent" s
care needs. In-home assessments can he highly ef-
ficient ways to save time in diagnosis, medical de-
cision-making, and communication among all team
members. These assessments may be performed by
physicians or by other health care professionals who
are in close communication with the physician, de-
pending upon the eircumslances."*

Patient Compliance. Noncompliance with therapy is a
common problem with respiratory patients. Estimated non-
compliance with medications in the elderly has been esti-
mated at 40-75%.^-'^ Pediatric populations show, similar
results.^*" Investigations of compliance w ith long-term ox-
ygen therapy (LTOT) suggest that compliance rates are
comparable. Six studies have found compliance rates of
45-14Vc (459;-. .^.^^f. .'56%, 65%. b5'/, . 74'70.'"''-^' Ad-
dressing noncompliance with oxygen therapy has been cited
as a primary recommendation in two recent consensus
conferences review ing the current status of long-term ox-
ygen therapy.'*-'*'

In chronic disease, noncompliance w ith therapy has been
shown to place the patient at higher risk of poor illness
management, increased symptoms, poorer functional sta-

tus, more missed days from work and school, more fre-
quent exacerbations, and even higher mortality.'*-''*^ With
I.TOT, failure to use oxygen as ordered can affect both
morbidity and mortality, as oxygen is the only form of
therapy shown to extend life span, and failure to use ox-
ygen for an adequate number of hours per day has been
shown to affect survival.'*'''*' Physicians are frequently crit-
icized for the lack of time spent in educating patients on
why they are using a therapy and how it should be used.'*'*
Monitoring the patient for adherence to the physician's
orders while providing education and support can both
prevent noncompliance and help reestablish compliance
where problems exist."''-'*"

Several factors have the potential to affect patient com-
pliance with therapy. Pepin et al suggested that factors
associated with effective use of oxygen are ( 1 ) initial pre-
scription for 15 hours or more per day. (2) supplementary
education on oxygen. (3) cessation of smoking. l4) use of
oxygen in all domestic situations (toilet, meals, leisure,
etc), and (5) absence of adverse effects from oxygen treat-
ment. Their conclusion was that attention to such factors
could optimize oxygen prescription and constitute goals
for patient education. '^

A recent report from the Office of the Inspector General
found that, although almost all patients w ith home oxygen
stationary systems used them. WA reported never using
their portable systems.'*'' The two most probable reasons
for this noncompliance are ( I ) the patients do not need the
portable systems or (2) the patients have continuing need
and are simply not using the systems as appropriate to
their needs. Since Medicare requires documentation of med-
ical need and the need for supplemental oxygen generally
increases during activity, the latter explanation is more
likely. In either case, additional monitoring and education
by RTs has the potential to reduce this waste of resources.

Improved .Allocation of Resources. .Although data on
the misallocation of respiratory home care resources in the
United States are sparse.'*" data from other levels of care
and other countries suggest that the potential for misallo-
cation is high. Misallocation of resources can take multiple
lorms in the home, including:

1. patients receiving respiratory services who do not
have documented medical need

2. patients receiving respiratory services who had doc-
umented medical need during an acute episode but no
longer require them after resolution of an acute process

?>. patients who have medical need but are not lecciv ing
services

4. patients receiving services prescribed at suboptimal
settings, dosages, delivery methods, or frequency

.'i. patients receiving services for which there is docu-
mented medical need but who are noncompliant in using
the services

480

Ri SPIKATORY CARt, • M\\ 2001 Vot, 46 No 5

Partnering tor Oni\i\i Ki spiratorv Homi Caki

All forins i)l'niis;ill(n.;itii>n Ikim.' ihc |iotcnii;il Id increase
iho cost of care. In the rnitd.! Stales, because Ihere is a
requirement lor (.locumeiiiatitm ol ineJical need tor most
respiralorN home care sersices (eg. owiien rei|iiiremenis).
it is unlikel\ that a large number of patients fall into the
first categorN .

l-!\perts at multiple consensus conferences have sug-
gesteii that patients ma\ fall mio the second category more
frequently. ''-■*-^-'''-'-' Consec|uent to increa.sing pressure for
early hospital dismissal, patients are being tlismissetl ear-
lier, while still reco\ering from exacerbations of chronic
states or acute illness. The potential e.\ists for phssicians
to prescribe respiratory serxices (eg. oxygen) based on
testing done during an acute phase, only to have the patient
continue on the service long after the acute phase, when
medical need no longer exists.

In .Spain. Farrero et al found that monilormg uith oxi-
melr\ during home visits led to the wiihdraual ot I.IOI
from 20 of I2S patients."^ This underscores a point made
b\ the hifih Oxygen Consensus Conference:

Patients who are discharged from hospitals f()lk)w-
iiig an cxaeerbalion with unstable respiratory dis-
ease requiring oxygen lherap\ should be recertified
after the initial 90 days of therapy with long-term
oxygen by repeat arterial blood gas analysis or ox-
ygen saturation measurements. These measurements
are medically necessary for the physician to evalu-
ate the course of the disease and to make adjust-
ments to oxygen flow or to discontinue oxygen if it
is no longer necessary. Once the need for LTOT is
established, repeal measurements of arterial blood
gases or saturation are not necessary or justifiable.'*'

The American Medical .Association suggests that a num-
ber of patients may fall into the third category: those who
have medical need for services but do not currently receive
them. The .American Medical Association states:

An estimated 20% of patients over 65 have func-
tional impairments with related home care needs.
Their physicians may be unaware of these needs
during the typical otTiee visit. For some relatively
functional patients, home care needs may be ade-
quately defined in an office setting. However, for
most patients, in-home assessments are preferable
and may e\en be critical. In-home assessments can
be highly efficient ways to save time in diagnosis,
medical decision-making, and communication
among all team members. These assessments may
be performed b\ physicians or by other health care
professionals vsho are in close communication with
the physician, depending upon ihe circumstances."*

Home RTs arc in an excellent position to pcrlorm home
assessments ami communicate the results to the physician.

It is cslimatcil that approximately half of COPD patients
lui\c been identified. Ihe .National Lung Health F.duca-
tion Program, a program endorsed by multiple physician,

clinical, and go\crnmental groups, is focused on improv-
ing identification of COPD through education of priinary
care physicians on spirometry testing. Certainly, increased
home assessment by RTs can result in better identification,
which is likely to increase the identified need for respira-
tory home care. It is important to note, however, that this
increased idcntilication of need does not translate directly
to increased total costs. If better home management is
available, the need for higher and costlier levels of care
may be prevented.-"-'" '-

Studies suggest that many patients may fall into the
fourth category: those prescribed treatment at suboptimal
settings, dosages, delivery methods, or frequency. A ready
example is l,TOT. Consensus conference participants cited
the nectl for indi\ iduali/ed adjustment of the oxygen pre-
scription, something that rarely happens in practice."-"'
Hvidence suggests that a substantial percentage of patients
on home oxygen may not he adequately corrected by their
current oxygen Hows. .Morrison et al found that in patients
with daytime arterial partial pressure of oxygen 2; 60 mm
Hg. Sp(, was more than ^HY/t for an average of 78% of the
time. In patients with daytime arterial partial pressure of
oxygen of < 60 mm Hg. S^,, , was more than 9{)'/c for an
average of 69% of the 24-hour period.'*''

Sliwinski et al found that despite ha\ ing an average Spo,
of 949r at the beginning of the recording, patients on ox-
ygen spent an average of 6.9 hours below Spo, of 90%.
with a minimum Sp,, of 61*"^. Most desaturations came
during sleep and naps. The study concludes. "The oxygen
flow prescribed, based on blood gas measurements at rest,
did not protect S.S"? of the patients studied from deep falls
in Sp,, during daily life."'"'

Carroll et al reported that 4 ol 10 patients showed sub-
stantial desaturation. with Sp, , decreasing to below 90%
for periods of l.S — \T^i of the monitoring time."' Gor/elak
found that nocturnal oxygen desaturation affects prognosis
in COPn patients, despite long-term oxygen treatment.""

Thera|iist-dri\cn protocols for monitoring and titrating
oxygen flows to an iiidi\ iduali/ed prescription ba.sed on
resting, activity, and nocturnal needs would probably cor-
rect this common error in prescription. To obtain maxi-
mum benefit from oxygen therapy, it is important to cor-
rect oxygenation al all times. In the .Nocturnal Oxygen
Therapy I'rial. hypoxemic patients who used oxygen an
average of h) hours per day (and presumably whose ox-
ygen levels were corrected for longer periods) lived sig-
nificantly longer than those averaging only 12 hours of
daily use.'**'

The fifth and final category — those with medical need
hut noncomplianl with care — constitute a substantial piob-
Icm. livery attempt should he made to im|irove compliance

Ri..si'IRatorv Cari^ • May 2()()1 Vol 46 No 5

481

Pakinkring for Opiimal Rhsi'ikatory Homk Care

through education aiul paliL-ni suppori. In \hc c\cni ihai ihc
patient chooses to remain nonconipliani despite these el-
forts, the physician should decide whether it is prudent to
leave equipment in place based on the current patient use
patterns.

In other settings, data indicate that K Is can decrease
misallocation of services, especially when therapist-driven
protocols are in place.'™'"' Multiple studies show that
the use of therapist-driven protocols results in improved
outcomes and decreased cost of care. This allows the phy-
sician more time to perform other duties and replaces house
staff (eg. interns, residents), who are less available because
of cuiTcnt trends in physician education and training. It is
reasonable to expect that the use of RT-driven protocols
would result in similar benefits in the home setting as well.

Monitoring Psychosocial Status. Clinically important
depression and other psycho-emotional disorders are com-
mon among patients with chronic illness, including
COPD."--"-* Though RTs are not qualified to directly
address those issues, they can certainly recognize their
impact on care and bring them to the physician's attention.
The therapist may indirectly assist in preventing or man-
aging these problems by addressing commonly linked is-
sues such as inactivity, frequent exacerbations, fears trom
ignorance of disease process, and lack of social interac-
tion, as has been demonstrated in pulmonary rehabilitation
programs. "'~"''

The patient's condition itself can have substantial im-
pact on the patient's cognitive status. Hypoxemia, hyper-
capnia, and poor sleep quality are common in chronic
pulmonary disease and directly affect the patient's con-
centration, memory, reasoning, and alertness. By monitor-
ing for the signs and symptoms of these conditions and
reporting them to the physician along with appropriate
recommendations for intervention (eg. inhaled bronchodi-
lators, oxygen therapy, noninvasive ventilation), these prob-
lems can be effectively managed.

"Physician Extender." By working under the direction
of the physician in monitoring the patient for response to
therapy, reporting important findings to the physician, and
making appropriate recommendations for adjusting the cur-
rent plan of care, the RT assumes the role of a "physician
extender" in the home setting. Although it is desirable for
the physician to directly visit the patient's home, it is
logistically difficult (if not impossible) for today's physi-
cian to visit every patient's home, even on a one-time
basis. Home care can be very effective in identifying new
problems that may not be discovered in the physician's
office.'"""-'-"

The American Medical Association recommends'-' that
each home care visit should include:

• a brief assessment of the oserall cftecti\eness of the
comprehensive home care program

• assessment of patient and caregiver interactions and
satisfaction with the home care program

■ identification of any new problems

• notification ol appropriate team members for follow-up
of new problems

■ encouragement and reinforcement of instructions from
other team members

The home RT is in an ideal position to provide this type
of feedback to the physician and other team members (eg.
ancillary health personnel [see Table 2| who pro\ide in-
home services). The therapist can also follow up on prob-
lems or concerns noted by "nonclinical" personnel and
relay pertinent information to the physician. For example,
during the delivery of a hospital bed, the delivery techni-
cian may note on the plan of service that the patient re-
ported shortness of breath with minimal activity. As the
physician may be unaware of this problem, the RT should
gather appropriate information and relay it to the physi-
cian, resulting in appropriate intervention. To ignore such
a finding would be irresponsible.

An essential element of this physician extender relation-
ship is trust. Trust is built between the physician and ther-
apist based on the demonstrated knowledge and skills of
the therapist. If the therapist faithfully pro\ides informa-
tion to the physician that is accurate, reliable, concise, and
important to the overall care of the patient, trust will grow.
The home RT must have strong assessment skills and the
ability to communicate effecti\ely with the physician and
patient. A trusting relationship based on multiple positive
contacts is conducive to the physician allowing the thera-
pist a growing role in the management of home care pa-
tients.

Physicians must likewise give therapists an opportunity
to prove their value in the home setting. This is done by
allowing therapists to actively participate in the home man-
agement of the patient and by being open to input and
ideas submitted by the therapist. The physician must real-
ize that by working effectively with the therapist, care can
be improved to everyone's benefit.

Benefits of Respiratory Home Care

The benefits of respiratory home care have been well
established by a number of authors, all aimed at improving
outcomes through comprehensi\e home respiratory ser-
vices. The addition of evaluation and follow-up visits by
RTs in the .South Hills Health .System project decreased
the need for hospitalizations in COPD patients from 1.28
admissions per patient the year prior to the program to
0.48 the year following. Average length of hospital stay
also decreased, from 18.25 days to 6.09 days.--

48:

RI•:splRATOR^ Care^ • M\\ 2001 Voi 46 No 5

PARTNKRINti lOR Ol'IlMM Rl SIMK A I ( )l<"l lll)\l| ('\R1

The "Rcspi-Carc" program targeted elimnic respiratory
patients with histories ol' t'ret|uent hospitah/atioii. li\ pro-
viding comprehensive home care, including RTs. to 17
patients with end-stage respiratory disease, they were able
to decrease hospitah/atioiis Irom S^l to .^.^ in equal time
periods before and alter the insiuuiion ot the program
Hospital days decreased from 1.181 before the program to
667 during the program, and emergency department \ isits
decreased from 105 to 64. Total costs savings were $.^2S
per patient per month ( IWl data).-"

Zajac demonstrated signiticant impro\ement m out-
comes by using RTs in a "Respiratory Wellness Program"
for managed-care organization members with asthma and
COPD. A cohort of MO COPD patients showed a 70'/;
reduction in hospii.il days and emergency department vis-
its. More than 95'/f of patients expressed satisfaction w iih
the program. '--

Warburton et al demonstrated im|innenioiHs m man-
aged care members with asthma. Participants showed im-
prcnements in peak flow meter use. personal best peak
How. lost productive days, lost productive days for child
care, use of inhaled corticosteroids, shortness of breath.
chest tightness, night awakenings. member-rept)rted hos-
pital admission rates, member-reported average length of
stay, annual admission rates, semi-annual ailniission rates,
and average length of stay.'-'

Weber et al demonstrated a reduction in health care
utilization in 45\ asthma patients who completed a "re-
spiratory wellness program" that included RT home \ isits
for patient instruction, self-care instruction, and patient
assessment. There was also a trend toward a reduction in
disease severity for patients who had participated for 3(){)
days or more.-'*''

In a separate project. Weber et al used RTs in an in-
home program to reduce health care utilization, and im-
prove quality of life and functional status in 349 COPD
patients. On a\erage, health care utilization (sum of hos-
pital days and emergency department visits) dropped from
3.4 to 0.4 in Stage I COPD. from 3.6 to 1.1 in Stage 2
COPD. and from 6.1 to 1.4 in Stage 3 COPD.'-'

Hendon and Kageler used an R T-delivered disease man-
agement program to reduce health care utilization in asthma
and COPD patients. Fifty-seven patients with asthma or
COPD showed significant reductions in emergency room
visits (1.75 to 0.32). hospitalizations (0.96 to 0.1 1 ). hos-
pital days (3.12 to 0,44), and lost productive days ((■).55 to
1.58). with improvement in quality of life.'-^

Roglieri et al demonstrated that RTs can be effeclise
case managers with asthma patients. Their program used
RTs to provide home visits lor patient assessment, envi-
ronmental assessment, education, self-care instruction, and
action plan implementation. Patients who completed the
program were more likely to adhere to asthma guidelines,
including increased use of anti-intlammatory drugs. '-''■'-''

Through the use of chronic disease management. Tiep et
al demonstrated a reduction in hospitalizations (treatment
group: 22 pre-referral vs 17 pt)sl-refcrral; control group:
34 pre-referral \s 46 post-referral, p < 0.05) and total
hospital days (treatment group; 177 pre-referral vs9l post-
referral: control group: 221 pre-referral vs 251 post-refer-
ral, p ■ ■ 0.05). They estimated savings in hospital charges
of $36().()()0 for the treatment group (n = 55) and S7()0,000
for the group as a whole (/; = 109). The yearly cost of the
program was S3()() per participant per year.'^^

Fields et al demonstrated substantial cost reductions in
technology-dependent children with the use of a compre-
hensi\e respiratory home care program. For 6 ventilator-
dependent children, the .savings were $79,074 ± .S26,558
per patient per year. For 4 oxygen-dependent children, the
savings were $83,187 ± $25,028 per patient per year.'''

Bach et al had similar results in 20 adult ventilator-
assisted individuals. The daily cost of caring for these
patients in the home was $235.13 ± $56.73. whereas Med-
icaid reimbursement for respiratory rehabilitation units was
$648-$7l9 per day.-'

Others ha\e found siinilar reductions in the need for
hospitalizations, outpatient care, and total costs with com-
prehensive home care programs. ■"•■'-•'-*-'2'

How Does Keiinhursement Affeel
the Quality of Care?

liiHucnce of Kquipnient Reimhursement Methods on
Quality of Care

Congress recognized the importance of close follow-up
when they crafted the definition of "Frequent and Sub-
stantial Servicing" in establishing payment categories un-
der the 6-point plan currently used in reimbursement of
home medical equipment under Medicare Part B:

This class of ilenis | requiring ticquent and substan-
tial servicing I would include those that are techno-
logically sophisticated and require frequent moni-
toring or adjuslnienl in order lo make sure the\ are
functioning proper!) oi being properly utilized hy
the palient.' "'

Common sense dictates that \ou cannot separate home
and patient \ariables from the equipment when ensuring
that the equipment is properly utilized by the patient. .-Xll
of the factors discussed above have direct impact on whether
proper utilization will occur. Appropriate follow-up hy
qualified personnel is essential to ensuring that patients
comply w ith physician orders. With oxygen therapy, non-
in\asi\e ventilation, invasive \entilation. and other tech-
nologically sophisticated home therapies, it is essential
that proper follow-up be available. Failure to provide such

Risi'iRAioKV Caki • May 2001 Vol. 46 No 5

483

Partnering for Optimal Respirator'i- Homf. Care

care ensures generalh pmir compliance and suboptimal
patient outcomes.

A quick review of equipincnt ihal has been mo\cd liom
the "trequent and substanlial servicing" category to the
"capped rental" category ot" Medicare's reimbursement sys-
tem can teach an important lesson. Under capped-rental.
items are rented for a predetermined period of time ( 13 or
15 months, depending on the patient's choice of purchase/
rent option), at which time payment is "capped." Because
of the limited reimbursement for these items, ongoing fol-
low-up by professionals is typically unavailable. Contin-
uous positive airway pressure devices were moved into
this category in 1995. Patients have demonstrated poor
compliance (less than 50% ) with continuous positive air-
way pressure, as monitored by the devices" hour meters.'"
hiterxentions such as those discussed above have been
demonstrated to improve compliance when available."^
Certainly the case can be made that moving these devices
(eg. continuous positive airway pressure, bilevel positive
airway pressure, nebulizers) to capped rental was a mis-
take that should be reversed.

Effect of Recent Cuts

The implementation of stringent guidelines on qualifi-
cation for home health \isits has dramatically decreased
the availability of nurses and other health professionals for
home visits via the home health agency.-' Furthermore,
implementation of a prospective payment system has driven
many home health agencies out of business.-'"'

The Health Care Financing Administration has enacted
several cuts in reimbursement for home respiratory equip-
ment, including oxygen, nebuHzer medications, and other
services, citing perceived overpayment for those services
based on the rates being paid by other providers (eg. Vet-
erans Affairs Department). The validity of their compari-
sons has been called into question by the Fifth Oxygen
Consensus Conference.**-'

These substantial decreases in Medicare payments for
home oxygen and other home medical equipment services
have caused many home medical equipment providers to
reevaluate the feasibility of employing RTs. Because there
is typically no direct payment for the services of the home
RT, the cost of the clinicians is absorbed by the HME/RT
providers. As cuts continue and profit margins decrease, it
becomes increasingly difficult to justify these added costs.
In response to these cuts in reimbursement, many HME/RT
companies have decreased the frequency of follow-up vis-
its by RTs to home oxygen patients, .Some have even
eliminated these visits. Many patients who once enjoyed
inonthK visits by RTs are now only visited quartedy (or
less often), and at times by nonclinicians. Further cuts in
equipment reimbursement via competiti\e bidding, the ap-
plication of inherent reasonableness, and other reductions

in ecjuipment reimbursement are currently being consid-
ered and proposed. It is also being proposed to move more
of these devices (eg, noninv asive ventilation, oxygen ther-
apy) out of the frequent and substantial servicing category
and into capped-rental. The impact on patient care, patient
safety, and patient outcomes would be devastating.

Unless these trends in reimbursement cuts are reversed,
home care is likely to degrade into a low service, "fast
food" commodity. -Service will be cut to a le\cl that neg-
atively impacts patient care. Numerous examples of poor
patient care secondary to service cutbacks have been cited
by patients and clinicians during recent conferences,*^
Home medical equipment and services will be provided by
individuals with inadequate training to provide the level of
support required by patients. This is at a time when all
trends point to a demand for higher qualilv home medical
care.

Discussion

Respiratory home care faces a tremendous paradox: dur-
ing a time of increasing need there is decreasing reim-
bursement for .services. Providers must respond to a nuin-
ber of challenges, including:

• Providing more definitive data on the benefits of re-
spiratory home care to patient outcomes (eg, function, qual-
ity of life, decreased hospitalizations, decreased total costs).
Substantive data on the benefits of respiratory^ home care,
especially in reducing costs, would be a major step toward
securing reimbursement for the services themselves rather
than just the equipment.

• Improved allocation of respiratory services (both hu-
man and equipment) to improve outcomes while maintain-
ing or reducing total cost. Providers must be judicious and
efficient in their use of skilled personnel (eg. RTs).

• Increasing credibility. Providers have faced criticism
concerning overpayment, overutilization. and other fraud
and abuse. Clear clinical guidelines must be de\eloped for
the proper application of respiratory home care services.
Therapist-driven protocols, which have reduced misallo-
cation in the acute care setting, may provide an effective
mechanism in the home as well.

Summary

There are many opportunities for the physician and home
RT to work together to provide high qualitv. home respi-
ratory care. The skills of the RT are well suited to:

• reduce misallocation of respiratory services
■assess the patient's respiratory status

• identify new or as yet unidentified problems and needs
of the patient

• evaluate the effect of the home setting

• educate the patient on proper use of the equipment

484

Ri^si'iRATORY Care • May 2001 Vol 46 No 5

Partnering iok Opiinui Rhspiratorv IIomi Care

• innnilDr the patient's response to tlK'raps. iiKliulini:
CDtiiplicatioiis 1)1' therapy

■ monitor the cc|uipnK-nt toi proper linieiion

• monitiir tor appropriate inlcetioii control procedures

■ iitakc appropriate recominenilations tor changes to cur-
rent tlieraps

• ail|iist therapy uiuler the direction of the physician
IJy working together, everyone benefits. The physician

benefits from increased access to important information
concerning the patient and the impact of the home envi-
ronment. This is accomplished in a much more efficient
and cost-effective manner than the physician visiting the
home, and allows the physician to focus on higher-level
tasks that require direct physician oversight. The RT ben-
efits by being able to function in a way more valuable to
the physician and the patient. By using the skills they have
worked hard to achieve, RTs have greater job satisfaction
than when they are placed in roles of delivering rote and
repetitive care that does little to challenge their skills and
fails to ha\e an important impact on care.

Finally, and most importantly, the patient benefits by
receiving closer monitoring, better education, and the sup-
port needed to allow for safe and effective home respira-
tory care. With the patient receiving more appropriate care,
quality of life improves, the need for hospitalization de-
creases, and costs and inconvenience associated with the
disease are lessened. Thus, the previously stated goals of
home respiratory care — to improve the patient's physical
well being, potential for productivity, and self-sufficiency
within the individual's limitations — are achieved.

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NM. et al. Objective measurement of patterns of nasal CP.AP use by
patients with obstructive sleep apnea. Am Rev Respir Dis 1993:
I47(4):887-S95.

126.

127.

128.

129.

488

Ri;spiR\TORV Cari • M A^i 2001 Vol 46 No 5

Letters

lj;ucn. aiWrcssinj! lupus i>l iiiiTL-nl inlcrc?.! or malcrial in Ri-scikatoky Cahi will be considered fur puhlicalii>n The Edilors may iRCcpl iif
decline a Idler iir edil uilhoul chanjiint: Ihc aulluir's views. The conlenl iif lellcrs as published may simply reflect ihe aulhnr's npiniiin i>r
inlerprelaliiin of inforinalion — nol standard practice or the Journal's reconimendatioii. Aulhtirs ot cntici/ed material will have the opportunity
to reply in prim No anonymous lcttcr% eiin he published. Type letter double-spaced, mark il 'For Publication." and mail it lo RHnKAtrmv Caki-.
6(10 Ninth Avenue. Suite 702. Seattle WA 'JSUM. Lelter> may also he suhinitled electronically at www.rcjoumai.com/online_reMiurcM.

Lung Collapse During Low Tidal

NOIiiiiu' \ I'litiJatlDii in \cutt'
ki'spiraCor) Dislriss S\ ndroini'

Kallcl ct al rcccnlU repuried a case of
acute rcspiralory disircss syndrome compli-
cated by retained secretions and lung col-
lapse.' The authors olTer a good discussion
ahoul the possible elTects of a low tidal \ i)l-
uine (V 1 1 ventilatory strategy on bronchial
hygiene. I think most clinicians would con-
cede that thes locus more ot' their attention
{a finite coinmoditN l on plati-au pressure,
ptisilive end-expiratory pressure, and o,\y-
genation indices than on bronchial hygiene
when assessing an ARDS patient. I would
like to add to the discussion b> conunenling
on the use of small V , in acute lung injury/
acute respiratory distress syndrome patients
with decrea.sed chest wall compliance, like
the authors' patient with increased abdom-
inal pressure. Though it is enticing to use
plateau pressure as a reflection of alveolar
distention, one must always consider the
contribution of chest wall elastimce to pla-
teau pressure, since plateau pressure is gen-
erated by the elastic slate of the total respi-
ratory system. When plateau pressure is
increased because of decreased chest wall
compliance, lowering already conservative
V.^ to avoid high plateau pressure can result
in atelectasis, deo.xygenation. and perhaps
as the authors suggest, retained secretions
as a consec|uence of unopposed increases in
pleural pressure.' ■' Lowering \', may be a
inistake. not merely a necessary evil of pro-
viding protective ventilation, since using a
V, that produces plateau pressures above
"protective"" limits (.^5-40 cm H;.0) in the
presence of decreased chest wall compli-
ance does not necessarily produce ventila-
tor-induced lung injury. Dreyfuss et al'
showed that when mechanically ventilated
rats were exposed to high ainvas pressures
because a strap v\as placed around the tho-
rax, ventilator-induced lung injury does not
(K'cur. I agree with the authors" suggestion
that bronchial hsgiene measures should be
given more attention when using a low V,
ventilatory strategy. However, we must also
be inindful not to unnecessarily lower V^ at
the behest of a potentially misleading ven-
tilatory target. Until we have better methods

of measuring iranspulnumary pressure, we
must rely on global respiratory system mea-
surements, which need to be inter|iretetl cau-
luuislv when assessing lung mechanics

.klTrcv M Havnes KKI RPKI

Depailiiicnl ol Kcspiialorv Ihcrapy
St Joseph Hospital

Nashua. New Hanipshia-

RKKKRKNCES

1. Kallcl KM. .Sii.hal MS. Alonso JA. War-
iicckc hi., Kal/ JA. Marks JD. Lung col-
lapse during Icm tidal volume ventilation
in acule respiratory distress syndrome Rc-
spir Care 21K)1 ;46( 1 ):49-52.

2. Muloh T. Lamm WJE. Enibree LJ, fliklc-
brandt J, Albert RK. Abdominal distension
alters regional pleural pressures and chest
wall mechanics in pigs in vivo. J AppI
Physiol I991;7()(6):261 1-2618.

3. Dreyfuss D, Soler P, Basset G, .Saiimon Ci.
High inflation pressure pulmonary edema.
Respective elTeels of high airway pressure,
high tidal volume, and positive end-cxpi-
raUiry pressure, ."km Rev Respir Dis lyXS;
I37(5l:ll.'sy-ll64.

The aiitlnir rcspoiuls:

Mr Haynes raises a valid point when he
questit)ns the need for radical tidal volume
(V.,.) reduction in patients with acute respi-
ratory distress syndrome (.\RDS) and re-
duced chest wall compliance (C^ ^l- Early
on in the development of lung-protective
ventilation in ARDS, a target end-inspira-
tory plateau pressure (Pplat) of 35 cm H3O
was chosen because under conditions of nor-
mal lung-thorax mechanics, the lungs gen-
erally reach total capacity at that transpul-
monary pressure.' Later on, the target F,,, \|
range was reduced to 25-30 cm H,0 be-
cause further ev idence suggested that lung
injury may occur at lower pressures.- There-
fore, it has been assumed implicitly that, in
ARD.S, Q.\v is normal (152-285 niL/cm
II ,()).' ■" As Mr Haynes correctly observed,
animal models of .\RD.S have demonstrated
that when lliiircudiihcldiiiiiuil strapping is
used to reduce C", \\. lung injury does not
occur at Ihe expected levels of P,,, .^ , . thus
giving birth to the concept of "volutrauma""

as an important factor in ventilator-induced
lung injury.'' In fact, several studies'' " have
reported inarkedly reduced Q^v (75-137
iiilVcm H.f)| in .ARDS patients. Therefore.
It would ap|K'ar that our attempts to impose
radical V, reduction (4-5 mL/kg) to achieve
a desired P|.| ai ^'<iy ^ unwarranted.

However, this situation may not be as
straightforward as Mr Haynes suggests.
I'irsi. the mechanical properties of the chest
wall are complex and do not conform lo a
simplistic model of a single elastic structure
coupled to the lungs. The chest wall com-
prises both the rib cage and the abdominal
wall, each with a distinct compliance.' Fur-
thermore, additional complexities are added
when body posture changes or when large
applied forces distort the surface shaivs.'' In
the supine position during spontaneous
breathing, the nb cage contributes onh 40%
to tidal ventilation.' In contrast, during con-
trolled mechanical ventilation at the same
\' J. the rib cage accounts for over 7()9i- of
displacement, as the lower abdominal wall
compliance becomes apparent when it is pas-
sively displaced." In the supine position,
small V| ventilation and the volume-
enhancing effects of posiiiv e end-expiratory
pressure are preferentially distributed to the
ventral portions of the lung.'" This discrep-
ancy between rib cage and abdominal wall
compliance is greatly magiiified under con-
ditions ol' inlra-abdiiminal hypertension,
when the abdominal contents protrude into
the thoracic cavitv and alter intrathoracic
pressures. ' ' When I hav e observ ed chest ex-
cursions during contiolled ventilation in
these patients, olten only the upper chest
appears to be displaced. Therefore, it is pos-
sible that what WDuld constitute a lung-pro-
lectiv e V I (6 -7 mlTkg ( in patients w ith nor-
mal C( \\ . may cause regional overdistention
and ventilator-induced lung injury in a pa-
tient with abdominal compartment syn-
drome. The fact that this apparently did not
luip|icn when the V, was increased from
4.5 to 7 mL/kg in our case does not pre-
clude the possibility. When it appears that
Q \\ is globally reduced ( ie, because of gen-
erali/c\l tissue edema from sepsis'- or from
muscular rigidity due lo fentanyl adminis-
tration'), then I would agree with Mr Haynes
that limiting P,., ^i assumes less importance.
However. 1 would urge caution in deviating

RiisPiRATORV Cari: • May 200 1 Voi 46 No 5

489

Letters

from lung-protecliNi" xcnlilalion goals of
Pp,^.|. < 30 cm H ,{) when Jiniinishcd C, ^^
occurs because of cicvalcd iiuia-alxloniiiial
pressure.

Richard H Kalitt MS RRT

Res|iiialor\ Care Ser\iees

Dep;irinient of Ancstliesia

University of California, San Franeiseo

San Francisco General Hospital

San Francisco, ralilornia

REFERENCES

1. Marcy TW, Marini JJ. Inverse ratio venti
lation in ARDS: rationale and implemen-
tation. Chest PWl;l()()(2):494-5()4.

2. Tsuno K, Prato P. KoUibow T. Acute lung
injur, from mechanical ventilation at nmd-
erately high airway pressures. J .■Xppl
Physiol 1990:69(3):956-961.

3. Grimby G, Hedensliema G, Lofstrom B.
Chest wall mechanics during artificial ven-
tilation. J Appl Physiol 1975;38(4):576-
580.

4 Van l.ilh P. Johnson FN. Sharp JT Respi-
ratory claslanccs In relaxed and paraly/ed
slates in normal and abnormal men, J .■\pp\
Physiol l9fi7;23l4):47.'S^86.

."i Drcyfuss D, .Soler P, Basse! G. Saumon G.
High intlation pressure pulmonary edema:
respective effects of high airway pressure,
high tidal volume, and positive end-expi-
ratory pressure. Am Rev Respir Dis 1988;
137(5):1 159-1 164.

fi. Katz JA. Zinn SB, Ozanne GM, Fairley
HB. Pulmonary, chesl wall, and lung-tho-
rax elastances in acute respiratory failure.
Chest 198l;80(3):.3()4-311.

7. Conti G, Vilardi V, Rocco M, DeBlasi RA,
Lappa A, Bufi M, et al. Paralysis has no
effect on chesl wall and respiratory system
mechanics of mechanically ventilated, se-
dated patients. Intensive Care Med 1995;
21(IO):Kt)S-812.

S. Kallet RH, Campbell AR. Alonso JA, Mora-
bito DJ. Mackersie RC. The effects of pres-
sure control versus volume control assisted
ventilation on patient work of breathing in
acute lung injury and acute respiratory dis-
tress syndrome. Respir Care 2000;45(9):
1085-1096.

Smith JC. Loring SH. Passive mechanical
properties of the chest wall. In: Fishnian
AP. Macklem PI. Mead J. Geiger SR, ed-
itors Handbook of physiology. Section
3 — The respiratory system. Vol III: Me-
chanics of breathing. Chapter 25. Bethesda:
American Physiologic Society; 1986: 429-
442.

Bindslev L, Hedenstiema G, Santesson J,
Norlander O, Gram I. Airway closure dur-
ing anaesthesia and its prevention by pos-
itive end expiratory pressure. Acta Anaes-
thesiol .Scand 1980:24(3): 199-205.
Cullen DJ, Coylc JP. Teplick R. Long MC.
Cardiovascular, pulmonary, and renal ef-
fects of massively increased intra-abdomi-
nal pressure in critically ill patients Crit
Care Med I989;17(2):l 18-121.
12. Nuytinck JK, Goris RJ, Weerts JG, .Schill-
ings PH, Stekhoven JH Acute generalized
microvascular injury by acti\ated comple-
ment and hypoxia: the basis of adult respi-
ratory distress syndrome and multiple or-
gan failure? Br J Exp Pathol 1986;67(4):
537-548.

47th International Respiratory Congress
December 1-4 • San Antonio, Texas

4yu

Respiratory Care • May 200 1 Vol 46 No 5

Ki'vjcus of ItiMiks aiul Other Mi-tHu. Note lo publi\hcrN; Send review copies ol h(K>k.s. films,
liipcs. ami soliwaic lo Rimikaiok^ Cakl. WX) Ninth Avciiuc. Suite 702. Seallle WA y«l()4.

Books, Films,
Tapes, & Soriware

ln\in iiiul Rippc's liili-nsi\i' Can- Medi-
ciiif, 4ili celilum I J \oltiriii.- sell l<n.li;inl S
Irwin MD, Frank B Ccrra MD. James M
Rippc MD. Rdilors. Philadelphia: Lippin
LUll Kavcn. 1^)W, llardcinor. ilkislralod,
2.5 1 y pages. S225.

Now in its foinih ediuoii, li«iii and
Rippe's Intt'nsJM- ("arc Mi-dicinc has be-
come one ot the iiuisi po|nilai eritical care
reference books in the I'nilcd .Stales. The
editors" stated goal is to create a book with
a multidisciphmiry approach to eritical care.
Though the scope has broadened in this edi-
tion, the editors wanted lo preserve a prac-
tical and clinical approach lo the critically
ill. They have achieved their goals and cre-
ated an impressive relerence tool that is the
most complete of all the major critical c;ire
textbooks.

This is a thick lwo-\okiine levlbook that
addresses all aspects ot intensive care metl-
icine. The books come in handsome blue
covers. The paper is a bit thin and Iragile.
but the binding held up well lo wear and
tear. The text was easy lo reatl and the ed-
iting was excellent, w illi only a lew typo-
graphical errors noted.

The editors ha\e assembled o\er .^00 au-
thois lo write 227 chapters grouped into 18
sections. The authors ;ire tor the most p;ul
experts in their fields, although there is a
clear bias tow;ird physicians from the edi-
tors" home institutions. The organization is
tradilional. based on medical specialty and
organ system. There are also sections on
intensive care unit (ICU) procedures, phar-
macology/poisonings, surgical problems,
shock, transplantation, nulrilion. and a sec-
tion on moral, ethical, and legal issues in
intensive care. The sections are quite thor-
ough, with multiple chapters in each, usu-
ally organized by diagnosis. The chapters
are all quite detailed and extensively refer-
enced.

The traditional sections include cardiol-
ogy, pulmonary, renal, gastroenterology, in-
fectious diseases, endocrine, heiiiatology.
neurology, psychiatry, and rheumatology.
The most complete of these sections were
the pulmonary, psychiatry, and endocrine
sections. In the pulmonary section there
could ha\e been more information on me-
chanical ventilation, but the other pulmo-
nary chapters were excellent, especially the

chapters on basic physiology antl exlrapul-
monary causes ot respiratory tailure. Ihe
crulocrine section contained detailed inlbr-
niation on numerous subjects that are often
misunderstood by inlensi\ists. such as thy-
roid disease and mineral metabolism. I
would have liked to see more infonnation
on controversial areas such as relative ad-
renal insuttlciency in the ICf' and ihc use
ot growth hormone.

The cardiology parts ot this textbook arc
split into twd sections: one on carilio\ascu-
lar problems in the ICL' and the other on
coronary care. I found the separation a bit
arbitrary, with valvuhir disease covered in
one section and heart failure and ischemia
covered in the other. Overall, this section
was one ot the w eaker parts of the textbook,
often filled with more dogmatic statements
rather than recommendations based on e\'-
iilence (eg. volume loading in right ventric-
ular infarction).

The section on gastroenterology was well
w niicn hut less extensive than the other sec-
lions and probably deservcii more detailed
coverage. The renal, hematology, infectious
disease, neurology, and rheumatology sec-
tions were all well written and covered a
broad range of relev ant topics.

The other sections of this textbook were
innovative and covered information often
not available in other medical critical c;ire
bot)ks. The section on proceiiures and mon-
itoring is one of the highlights of this text-
book. This section devotes over 280 pages
to monitoring and procedures ranging from
arterial lines to percutaneous bladder tube
placement. The figures and the technical as-
pects of this section are excellent.

The sections on echocardiography . chest
lube placement, and tracheotomy are par-
ticularly good. An innovative section on in-
vasive radiologic procedures was very use-
ful. My only problem with this section was
that some of the conclusions made on in-
teipretation of data (eg. pulmonary arterial
catheters) were a bit superficial and in some
cases based on dogma rather than strong
support in the literature.

The pliarnuicoloyy and poisoning section
was excellent, with informative chapters on
kinetics followed by a great chapter on the
general approach to the poisoned patient.

The section then covered an extensive list
of common poisonings.

The surgical, transplant, nutrition, and
shock/trauma sections were very g(K)d. al-
though there were some areas not addressed
(eg. the role of enteral nutrition in acute
pancreatitis). Every chapter is very well ref-
erenced, which makes further research on
topics not fully covered in the text very easy.

The scope of this textbook is impressive
and each topic addressed is thoroughly cov-
ered. In general, the writing is excellent and
well organized. There are some holes in the
coverage, but that is expected in a b<x)k
covering a field as broad as intensive care
medicine. Compared to similar textbooks,
this is the most broad-based in its applica-
bility and is clearly the textbook to be shelved
in every ICU library. However, its organi-
zation assumes a lair amount of familiarity
with the subject mailer, which nuiv limit the
use of the textbook lo those more experi-
enced in the field. Critical care practitioners
would probably w ant to own this book and
use it as the definitive reference in caring
tor the cnlicallv ill. ll is too detailed to be
read cover to cover by fellows studying for
the boards, and likewise may be unneces-
sarily complete lor residents or critical care
nurses. Respiratory therapists, clinical nurse
specialists in critical care, and critical care
tellows will definilelv want access to it while
in the ICU. Overall 1 think the authors have
created the definitive textbook for care of
the critically ill patient and should be com-
mended on their effort.

Benjamin I) .Medoff MD

Department of Medicine and

Pulmonary anil Critical C;u"e Unit

Massachusetts General Hospital

Boston. Massachusetts

Procedures and rfclinique.s in Intensive
Care Medicine. 2nd edition. Richard S Ir-
win MD. .lames M Rippe MD. Frank B
Cen-a MD. Frederick .1 Curlcv MD. and Ste-
phen O Heard MD. Fditors. Philadelphia:
Lippincott Williams & Wilkins. 1999. Soft-
cover, illustrated, .^07 pages plus index,
$.59.9.5.

This is an amhilious. niullidiscipliiuuy
b<.x)k whose aim is the explication and teach-
ing of almost all priK'cdures done in the
intensive ciire setting. It is published both as

Rhsi'iK.MOK'i C.\Ki: • M.w 2001 VoL 46 No 5

491

Books, Films, Tapes, & Software

a stand-alone volume and as the first sec-
tion of a full-scale critical care text edited
by the same authors. Though the authors
suggest a wide titrget readership (ranging
from surgeons to emergency medicine phy-
sicians and nurses), the presentation appears
more attuned to the needs of house staff
rotating on an intensi\e care service: broad-
based, not too detailed. Ibcused on skills
they will actually use. Nurses and respira-
tory therapists will probably find the level
of detail proNided about setup. c;u"e. and use
of the described equipment insufficient to
guide day-to-day practice.

The stand-alone paperback book, pre-
sumablv offered as a lower-cost alternative
to the full textbook, compromises pocket-
ability in favor of full-size illustrations. The
typesetting is professional: the text is crisp,
clear, and legible. The illustrations are black-
and-white, but of unesen quality. The ma-
jority of the illustrations were done by a K
Powell, and they boast clean outlines, sub-
tle shading, and sufficient detail to guide
the practitioner — they are excellent. Other
illu.strations and some photographs, how-
CN'er. appear to have been digitally scanned,
with disappointing results: the photograph
of a pacemaker (page 74). for example, has
no legible buttons.

The book lacks internal structure, most
likely a result of its origin as a part of a
larger text. Each procedure is discussed in a
sep;irate chapter. There is no formal group-
ing into sections or systems, but there seems
to be a general progression from line place-
ments through cardiac to pulmonary, gas-
trointestinal, and neurologic/neurosurgical
procedures. .Some procedures on the list
seem less than "critical" — joint aspiration,
for example — whereas others are oddly ab-
sent: cardiopulmonary resuscitation and ad-
vanced cardiac life support ;ire onh briefly
mentioned in the chapter on defibnllation.
and the technique of intraosseous blood-
stream access is not discussed at all. The
book is focused on the care of adults; pedi-
atric-specific issues are covered poorly if at
all. Another consequence of the book's or-
igin within a full-size text is the overwhelm-
ing number of references. There are 194
references in the chapter on placement of a
pulmonary artery catheter — far more than
are needed to understand the pr(x;esses of
insertion and troubleshooting.

The wide variety of procedures per-
formed in the intensive care setting leads to
great \ariance in the amount of coverage
offered to each. Artenal puncture, for ex-

ample, receives a 4-page chapter quite apart
from the 1 pages already devoted to place-
ment ami care of arterial catheters, whereas
the exceedingly complex and speciali/cd
topic of temporary mechanical assistance for
left ventricular failure receives a scant 8
pages of discussion. The result is that the
book cannot be relied on to successfully
troubleshoot the more complex devices,
though it does provide a sound introduction
to their operating principles.

The text offers several in\iling high
points. Percutaneous tracheostomy receives
detailed attention and excellent photo-
graphic illustration. The endoscopically
guided placement of feeding tubes is well
described. The review of dialysis contains
an excellent discussion of dialysis theory,
simplifying this complex subject as well as
providing an excellent practical guide. The
mechanics of central and arterial line place-
ment and chest tube placement are also well
described.

On the other hand, some chapters simply
lack critical care "common sen.se." The
opening chapter, on endotracheal intubation
and airway management, contains this as-
tounding statement: "Since patients requir-
ing intubation often have a depressed level
of consciousness, anesthesia is usually not
required." These authors clearly do not rou-
tinely work in the intensive care setting!
The chapter on neurologic monitoring of-
fers an illustration of the placement of leads
for somatosensory evoked potentials —
which would generally only be placed by a
specially trained technician — but neglects
to provide an image or explanation of a ven-
triculostomy drain setup, perhaps the most
commonly used monitor the average nurse
or house staff officer will see.

This second edition text also suffers from
a certain complacency. .Some chapters that
slipped through largely unaltered from the
first edition should have been more heavily
revised. Some techniques described are sim-
ply outdated. Calheter-through-needle tho-
racentesis kits, though described eloquentl>
in this text, have been superseded by cath-
eter-over-needle kits, which eliminate the
risk of shearing off the catheter. Glass
syringes for arterial blood gas samples are
museum pieces. Other newer techniques are
left out. Noninvasive ventilation, a rapidly
growing modality of ventilatory support,
receives no mention whatsoever. Likewise,
discussion of ultrasound guidance for cen-
tral venous catheter placement — a cle;u- ad-
vance in ease antl safety of performing these

procedures — is absent. Diagnostic perito-
neal lavage is covered; measurement of ab-
dominal compartment pressure is not.

This book is caught in an awkward ad-
olescence. It spent a happy childhood as a
practical procedure manual for a number of
basic intensive care unit procedures. These
chapters are w cU w ritlcn, if a bit dated, and
detailed enough to be the sole reference of
a house staff officer contemplating a late-
night thoracentesis. Having discovered
wider horizons — the roles of endo.scopy,
bronchoscopy, dialysis, and advanced tech-
niques of circulatory support — it is strug-
gling to keep up with the hip kids down the
street. The chapters dealing with these top-
ics are current at the price of incorporating
less detail. They would be of more use for
discussing the merits of a procedure on
rounds than actually performing it. Still, the
authors are to be commended for their ef-
fort: concise coverage of these topics in an
easily accessible book is in itself a worth-
while goal.

Overall, this book is well suited to the
needs of a fairly nanow target audience:
house staff officers rotating through a gen-
eral intensive care unit. Nurses and respira-
tory therapists will find it helpful in explain-
ing some uncommon procedures. It would
be a worthwhile addition to the general ref-
erence shelf in any break room.

George N Giacoppe MD

Department of Medicine

Division of Pulmonary and Critical Care

Madigan Army Medical Center

Tacoma. Washington

Handbook of Pediatric Intensive Care,

3rd edition. Mark C Rogers MD and Mark
A Helfaer MD. Editors, Philadelphia: Lip-
pincott Williams & Wilkins. 1999, Soft-
cover, illustrated, 994 pages. S49.9.S.

The third edition of Handbook of Pedi-
atric Intensive Care, edited b\ .\Lu-k Rog-
ers and Mark Helfaer. represents a change
in overall focus. Previous editions seemed
to be designed to limit detail and give more
of a "what \ou see. how you treat it" ap-
proach, w hereas this edition seems to greatly
expand on detail provided and to focus less
on easy-to-use algorithms. The increa.se in
infonnation pro\idcd makes the handbt)ok
overall a more complete reference than ear-
lier editions. The down side is that with the
increase in content comes a large increase
in size and weight. This handbook is im-
possible to fit in a coat pix-ket or to carry
around easih . This ma\ make it less desir-

492

Resfiraiorn- Care • Ma'i 2001 Vol 46 No 5

Books, Films, Tapes, & Sojtware

able as a reference thai is easily fKirtable
and p<Kkel-si/eil. In aildiliun. ihe deplli of
inl'oniiation pro\ idcd in the handbixik com-
pared to the lull text niakes it almost not
worth having both. Conversely, the advan-
tage 1)1 having a more complete handbook
at a smaller si/.e and cost than the lull lc\l
is a distinct advantage in many circum-
stances.

The chapters are outlined in a lormat that
iiilows quick identification of specific top-
ics and where to find data regarding spe-
cific disease states, treatment algorithms,
and basic infonnation. The tables suffer from
lack of presentation to make them easier to
read, but are plentiful and useful in content.
The pediatric drug dosage guide in the ap-
pendix and the \arious commonly used for-
mulas are very helpful to medical personnel
at all levels of training and expenise.

The first few chapters deal with common
intensive c;ire unit subjects in terms of basic
cardiopulmonary resuscitation ;md airway
management. Though the majority of the
information is available in other texts and is
well known to most critical care providers,
a good o\er\iew of these subjects is pro-
vided. In a similar fashion, the basic overall
management of bronchiolitis and asthma is
presented at a level appropriate for multiple
specialties and levels of expertise. I found
regrettable the omission of discussion of in-
travenous terbutaline for asthma and the un-
common but potentially life-sa\ing role of
extracorporeal life support in these disease
states.

One of the major disappointments in the
book was the chapter on acute respiratory
distress syndrome. The coverage was very-
brief and little detail was given in regard to
the observed decline in mortality from this
disease. The general algorithm that outlined
management guidelines for acute respira-
tory distress syndrome w as useful. The chap-
ter regarding respiratory support and me-
chanical ventilation went in the other
direction — very comprehensive for a "hand-
book." The discussion of high-frequency
ventilation was lacking in detail, however,
and a table outlining general setup and use
of this modality for patients of different ages
and sizes would be of interest to those \v ho
use this modahty infrequently.

There were many chapters that covered
disease stales that are not I icquentls included
in a general handbook. Although these were
often much more comprehensive than per-
haps needed, the sections on neuromuscular

disease and cncephalopalhies were woilh-
while.

The cardiac sections were extremely well
done. Although the graphics of what car-
diac surgical repairs entail add pages to the
book, they are extremely useful in under-
standing what piiK'edures are perlorincd in
the operating rtx>m. Similarly, the graphics
of electrocardiograph abnormalities and
what to look for mc \ery useful.

In a similar fashion, the coverage of head
and spinal cord injury and central nervous
system subjects such as meningitis were very
good. A related topic, brain death, was also
well done, wilh good detail. The practical
aspects of care to successfully protect po-
tential donor organs to the lime of harvest
was very well done. This is an important
topic that is rarely discussed.

The remainder of the book was al.so fairly
comprehensive and covered most of what is
found in critical care. The only specific pop-
ulation that seemed lacking was oncology
patients — an important and difficult popu-
lation in critical ciu'e, especially as more
rigorous chemotherapy regimens lead to .sec-
ondary complications and the need for in-
tensive care.

For medical personnel who are interested
in critical care, this text provides a good
overall reference. As a general reference for
your personal library, the full Rogers Tcxl-
book of Pedicilru Intensive Care may be
more useful and easier to read. As a book
that can be carried along in a backpack, the
handbook will prove superior to Ihe full text-
book. Choosing which is best depends on
the specific needs and desires of the con-
sumer.

Heidi J Dalton MD

Pediatric Critical Care

Children's National Medical Center

Department of Pediatrics

George Washington University

Washington DC

Drugs in .\nae.sthetic and Intensive Care
Practice, 8th edition. MD Vickers MB BS
DA(Eng), M Morgan MB BS DA(Eng), PSJ
Spencer PhD DSc, MS Read MB BS. Ox-
ford: Buttervvorth Heinemann. 1999. Hard-
cover, illustrated. 526 pages. S55.

Since the first edition appeared in 1962.
this book has. over a period of 37 years,
proven itself to be one of the most impor-
tant references to drugs used in anesthetic
practice, by having a record of publishing 8
editions and 5 reprints

This eighth edition is btilh an expansion
and comprehensive revision of Ihe 1991
work. There are many changes in this edi-
tion. The phrase "intensive care" has been
added to the book's title, to become "Drugs
in Anaesthetic and Intensive Care Practice."
The reason for that change is the awareness
of a current development in intensive care,
which is "a clear requirement of trainees in
anesthesia, with the evidence that the great
niajorily of intensive care units in the L'nited
Kingdom are managed and generally staffed
by anaesthetists." The traditional title would
imply too narrow a focus in this modem
lime. Consequent to the change, a new au-
thor, Dr Martyn Read, has been recruited.
Naturally , the book'scoverage has been w id-
cned to include drugs applied in the inten-
sive care unit. All the existing chapters have
been updated and many have been reorga-
nized completely. Another addendum to this
edition is the inclusion of synonymous drug
names. When presenting a drug that has a
different name in Ihe l'nited Kingdom than
in the United Slates, the authors use the
United States name or the International Non-
proprietary- Name and give the British Ap-
proved Name in parentheses on first men-
lion within a section. The book now contains
526 pages and is an essential source of ref-
erence for all those involved in pharmacol-
ogy.

The primary audience of this book is train-
ees in anesthesia, who should find the book
an authoritative reference to the drugs they
use in daily practice and an essential aid in
preparing for fellowship examination. The
book is also an excellent reference source
for physicians when unusual situations oc-
cur. Moreover, it is also of value to respi-
ratory therapists and nurses, as their daily
practice also requires knowledge of many
of the drugs discussed in the text.

Overall, this book is clearly organized
and well written. It achieves its aim of suc-
cinctly reviewing most of the drugs used in
modem anesthesia and intensive care prac-
tice. The first chapter ("General Pharmacol-
ogy") and the 16th chapter ("Chemical
Transmitters and Enzymes") both give an
overview of phannacology information that
is succinct and up-lo-dale. There is one chap-
ter (Chapter 20) that deals with infusion flu-
ids and oxygen-carrying solutions. Each of
the other 17 chapters describes different
groups of drtigs. The groupings are under
different topics, such as therapeutic strategy
(eg, bronchcxlilation), groups of receptors
(eg, j3-adrenergic agonists and antagonists).

Respiratory Care • May 200 1 Vol 46 No 5

493

Books, Films, Tapes, & Soi rw arl

common chemical features (eg. bcn/odiaz-
epines). and action on the same organ or
system (eg, heart, circulation, uterus, or en-
docrine glands). The authors devoted the
beginning portion of each chapter to a re-
view of the phamiacologic basis oi that p;ir-
licular group of drags or therapy subject.
Monographs on different drugs or compo-
nents of that group and notes on similar
compounds that exhibit minor varialioiis
then follow.

One minor crilicism of the book is that
not enough emphasis has been placed on
unifying ways of presenting material among
authors; thus, the formal of the book suffers
a lack of uniformity:

1 . When a drug is discussed in a sep;irale
section, some authors give the page number
where the iriaterial w as previously discussed.
whereas others do not. For example, in the
review of haloperidol and droperidol. dif-
ferent materials concerning the two drags
have been separately mentioned in the be-
ginning portion and the monograph. How-
ever, there is no indication in the mono-
graph to inform readers about the pre\ ious
matenal. Readers who are only reading the
monographs for reference would miss im-
portmit materials in the earlier section.

2. Of the 20 chapters in the book, only 3
chapters (1, 3, and 16) included references.
Reference-free material makes the book
slimmer and easier to read. However, it lacks
evidence ba.se and fails to facilitate the ac-
quisition of further information.

The strength of this book is that it links
clinical conditions to pharmacology. There
are many useful summary tables and illus-
trations, which add substantially to the value
of the text. The weakness of the book stems
from the authors' attempts to have an en-
cyclopedic coverage, giving little in-depth
discussion to each individual entity.

The external appearance of the book is
appealing, and it is the si/e of most sland;ird
textbooks. The appendix provides quick ref-
erence tables to new recommended drug no-
menclature for the Liiiiled Kingdom, though
that would not be relevant to readers in the
United States. The index appears useful and
appropriate.

In summary, the authors have provided
an extremely concise, uselul. thorough, up-
to-date review of drugs in the context of
modem anaesthesia and intensive care prac-
tice. It is an excellent reference book for
medical students and residents who have
already had or are cunenllv taking courses
in anesthesia and critical care. Respiratory

therapists vmII deriiuielv benelii liom this
book.

Rick .Sai-Chucn Wu MD

FX'partmenl of Anesthesiology

China Medical College Hospital

China Medical College

Taichung, Taiwan

The liuumodynunilc Kft'ects of Nitric Ox-
ide. Robert T Mathie and Tudor M Grillitli.
I-Alilors. London: Imperial College Press.
1W9. Hardcover, illustrated. 5iH pages.
United Kingdom 133, United States $90.

Nitric oxide (NO) was identified as en-
dothelium-derived relaxing factor in 1987.
In the subsequent years, our knowledge of
the biological roles of NO has exponentially
grown, with the publication of over 35,()(K)
articles. Although there have been many fo-
cused review articles attempting to summa-
rize portions of this literature, this book rep-
resents one of the first attempts to prov ide a
comprehensive overview of the area with
an emphasis on the cardiovascular effects
of NO. The chapters ;ue written by recog-
nized international NO experts, with only
one third of the authors being from the
United States.

The book is divided into 3 sections: phys-
iology and biochemistry of NO. penplieral
vascular effects of NO, and clinical impli-
cations of NO. The first section consists of
1 1 chapters, which focus on the chemistry,
biosynthesis, and metabolism of NO. These
chapters are exceptionally well written and
present a complex mass of data in an un-
derstandable fashion. The use of well de-
signed figures adds to the comprehensibil-
ity of this potentially contusing subject. This
section of the book will be of definite value
to anyone involved in NO-related research,
and I have frequently used it as a reference
volume for manuscripts and grants.

The second section of the book consists
of 7 chapters that examine the effects ot NO
in regional circulations, including the brain,
heart, skeletal muscle, liver, intestines, and
kidney. These chapters present a balanced
view of the contradictory effects of NO in
many organs. Again, the infomiation is pre-
sented in a complete manner, and the au-
thors attempt to reconcile contradictory data
whenever possible.

The third section of the book consists of
(i chapters and examines the effects of NO
in ischcmia-reperfusion injury, atheroscle-
rosis, endothelial dysfunction, the pulmo-
nary circulation, systemic hypertension, and
septic shock.

In general, the chapters are comprehen-
sive and well-written. In contrast to many
textbooks in which the information in dif-
ferent chapters is contradictory, this book
avoids that problem and is edited to empha-
size the interrelationships of the chapters.
The chapters ;ire written at a state-of-the-art
level that can sometimes be challenging for
the casual reader. The majority of the chap-
iL-is ha\e (i\er 100 references, so that this
book could lia\e been a single source for
almost all information on NO that would be
needed by a researcher or clinician.

Unfortunately, the book has two impor-
tant limitations in this regard. First, although
the expressed purpose of the book is to pro-
vide a state-of-the-art understanding of NO.
most of the chapters are already substan-
tially outdated. The overwhelming majority
of references are from the period of 1 992 to
19%. when a detailed understanding of NO
was just beginning to be achieved. There
are few references from 1997 and almost no
references from 1998. Thus, the chapter on
septic shock refers to the 1996 clinical trials
of tumor necrosis factor (TNF-«). has no
references to the use of selective inducible
nitric oxide syntha-se (iNOS) inhibitors after
1995. and only refers to an abstract on the
beneficial hemodynamic effects of N-
monomethyl-L-arginine (L-NM.A): the fi-
nal results of the riuidomized clinical trial
indicated increased mortality with L-NMA.
Similarly, the discussion of the effects of
NO in acute respiratory distress syndrome
does not include any of the multiple clinical
tnals that focused on outcome: several of
these studies were presented at meetings in
1 997 and the phase 2 randomized study was
reported by Delliiigerct al in January 1998.'
Thus, this book, which was published in
September 1 999, no longer prov ides an up-
to-date source of information. It may be un-
av oidablethal a book will be outdated shortly
after its publication; unfortunateK. this is a
major problem in a field such as NO. which
is rapidly evolving.

The second major limitation of the book
(at least for many readers of Ri simkaiori
C.vRF.) is that the emphasis on basic science
and laboratory research data limits the
book's coverage of clinical issues. For ex-
ample. I anticipated that there would be ex-
tensive coverage of inhaled NO. However,
there are only two paragraphs on the effects
of inhaled NO in acute respiratory distress
svndrome. one paragraph on inhaled NO
and persistent pulmonary hypertension of
the newborn. ;ind one paragraph i)i\ inh;iled

494

Resimkaioky Care* Ma> 2001 Voi 46 No .^

Books, Films, Tapes, & SoKrwARt

NO ;itul priiiian piilmonan, hyiKTlciision.
Ill llic ch.iplcr on the role nl NOS inhihitmn
ill scplii.' sliiKk, llicrc arc 7 paragraphs on
animal studies and only 2 paragraphs on
humiin studies. The chapter on the role ol
NO in ischcniia-rc|X'rt'usion injury is excel-
lent but rclers to no clinical studies.

In the past 2 years, over 10 bixiks on NO
have been published, each of which pro-
vides an excellent overview of the field. The
Hat>ni(Hlyn;)niic Effects of Nitric Oxide
distinguishes itsell h\ pio\idlng a compre-
hensive but understandable approach that
will primarily be of \alue to researchers in
this important subject.

Ronald (. I'tarl .MI) PhD

Department of Anesthesia

Stanford University school of Medicine

Stanford. California

REFERENCE

I. Effects of inhaled nitric o.xide in patients
with acute respiratory distress syndrome:
results of a randomized phase II trial. In-
haled Nitric Oxide in ARDS Study Group.
Cril Care Med 1998;26( I ):I.S-2.'*.

Thoracic .Anaesthesia: Principles and
Practice. S Ghosh BSc MBBS and RD
Latimer MA MBBS Oxford: Buttcnvorlh
Heinemann. 199^. Harilciner. illustrated,
335 pages. $85.

Thoracic surgery has evolved from a
high-risk, high-mortality attempt to save life
into a highly specialized field directed to-
ward the diagnosis and lieatmeiu of many
intrathoracic conditions. The mortality rate
associated with thoracic surgery has contin-
ued to decrease, despite the fact that sur-
geons are operating on older, sicker patients.
Thoracic surgery presents a unique set of
challenges to the anesthesiologist entrusted
with the care of these compromised patients:
not only must they ensure patient safety,
they must also optimize the surgical field.
The challenges include the care of a patient
whose underlying pulmonary compromise
leaves little room for error, in the face of
their physiologic derangement and the need
for one-lung ventilation. Anesthesia for tho-
racic surgery encompasses a broad spectrum
of topics, including the physiologic, ana-
tomic, phannacologie. and clinical consid-
erations for the patient undergoing pulmo-
nary and esophageal surgery.

Thoracic .Anaesthesia: Principles and
Practice does an admirable job of allempl-

ing to cover the broad spectriiin of thoracic
anesthesia in an easily read, inlcrcsiing. and
inloriiiati\e volume. The text is written by
many different authors, each of whom brings
cxpenise and experience to different sec-
tions of the book, which covers the whole
scope of thoracic anesthesia. Each chapter
addresses a specific topic and is complete in
itself. The text is directed at the anesthesia
care provider who will be adminislering
anesthetic to patients undergoing thoracic
surgery.

This book is not only directed toward the
anesthesia no\ ice. but also to the senior an-
esthesiologist who would like lo refresh his
or her knowledge or baish up to take an
examination. Tlic anesthesia resident who
will be taking care of these patients for the
first time and who needs a thorough back-
ground in the anatomy, physiology, and pro-
cedures will benefit from the information
contained in this text. An in-depth tlescrip-
tion of the surgical priKcdures. their indi-
cations and contraindications, as well as pit-
falls and common complications associated
with the procedures are addressed. This text
is also useful for the senior anesthesia care
provider, who may use it as an aide-memoir
or for teaching purposes. The use of table
summaries at the end of each chapter makes
this a valuable book for review.

The initial chapters deal with the histor-
ical perspective of thoracic surgery and how
the field of iuicsthesia developed from a
ri.sky, high-mortality pursuit to the modem,
relatively safe administration of anesthesia
with improved equipment and safety mea-
sures. It gives useful background informa-
tion to the reader interested in the e\oluiion
of this field and what challenges prompted
the development of much of the equipment
in use today. The use of illustrations and
photographs enhances this chapter and gives
an appreciation of the obstacles presented
to those early pioneers in the field and how
they overcame them. L'ndoubtedly the
equipment in use today provides patients
with a safer and gentler anesthesia than was
administered in the past.

A discussion of the physiology of one-
lung ventilation follows, with particular fo-
cus on the effects of anesthesia and paraly-
sis. This chapter will be useful to all
anesthesia care prov iders. nurses, and respi-
ratory therapists who care for these patients
intra-operatively and post-operatively in the
intensive care unit. The author of this chap-
ter writes for the medically U-ained practi-

tioner who already has a working knowl-
edge of pulmonary physiology.

A very brief and superficial chapter on
the anatomy "f the lungs, with many dia-
grams (not always related to the text), com-
pletes the first part of the b<M)k. The indi-
cations and techniques for one-lung surgery
arc discussed in detail, with a focus on pit-
falls, complications, and approach to treat-
ment of these known complications. The
chapter is thorough and logically written
and provides many useful tips to avoid pit-
falls for the inexperienced anesthesia care
provider caring for these patients for the
first time.

The following chapters (5-9) focus on
the specific operations carried out on the
lungs, pleura, diaphragm, airway, and esoph-
agus. The authors have thoroughly re-
searched each disease process, the surgical
procedure, and the anesthesia care these pa-
tients require. .An in-depth review of the
pre-opcrative. intra-operative. and post-op-
erative complications that can occur in this
patient population is provided for each spe-
cific procedure and how it should be diag-
nosed and treated. These chapters will be of
use to any health c;ire prov ider who cares
for these patients before, during, and after
their surgery. They are especially helpful to
the iuiesihesia care provider who will be
intimately involved with the admini.sttation
of the anesthetic during the surgical proce-
dure. The intensive care unit staff who care
for these patients post-operatively will ben-
efit from a working knowledge of what oc-
curred intra-operatively. as this will lead to
better postoperative care and anticipation
of expected complications.

A discussion on newer techniques, such
as video-assisted thorascopic surgery and
lung volume reduction surgery, is included
and discussed in detail. This section will
really only be of interest to the operating
room anesthesiologist, as none of these pro-
cedures occur out of the operating r(X>m.

The field of pediatric thoracic anesthesia
is addressed in the next chapter, with a de-
scription of much of the ehildhiHid pathol-
ogy that warrants such anesthesia. This topic
can easily be discussed as a textbook in its
own right, and this chapter makes ;in admi-
rable attempt to cover this vast topic in a
short space, but lacks the depth of infoniia-
tion required lo really take c;u-c of these
children undergoing thoracic anesthesia.
The specific workup of these children is
directed to the requirements of the British

Rfspiratory Carl • May 2UU1 Vol 46 No 5

495

Books, Films. Tapes, & Soi twaku

medical system and ma> be i|iiile difleienl
in the Amenean medical cinironiiienl

The final chapters of this bocik deal with
piist-operative pain relief, commonly seen
post-operative complications and modes of
respiratory suppon. as well as the contro-
versies in the field between the dillerent
schools of thought. This linal chapter shows
that experts in their fields have opinions
that ditfer from one another. It gives the
novice an insight into an evolving and ad-
vancing field, while allowing one the lee-
way to develop one's own anesthesia prac-
tice within the guidelines recommended in
this book.

The book is relati\el\ short. .^.^5 pages.
and light enough to cany around. It is well
laid out and has an easy-to-read style, w ith
good use of pictures, tables, and graphics. I

think that the summaries at the end of most
ol the chapters will be helpful to those us-
ing this book as a study aid. The informa-
tion is factual, informative and accurate. The
index is useful for quick reference to the
key concepts put forward in the book.

In summary. I feel that the editors
achieved their stated goal of pro\iding a
useful text for the benefit of junior and se-
nior anesthesiologists administering anes
thesia for thoracic surgery. The terminol-
ogy is written in the Knglish style with the
use of ""theatre" for ""operating room" and
"high dependence area" for ""intensive care
unit," which In no way detracts from the
valuable infonnation that it imparts to the
reader. 1 do not think this is a book that
would be of prim;u7 interest to the respira-
torv therapist or bedside nurse, as it is mostly

directed at pre-opcrative and intra-operative
care, though some of the chapters may pro-
vide insight into a patient's post-operative
course. Very little post-operative informa-
tion is given for these patients as, on the
whole, anesthesiologists are not responsible
for the post-operative care of these patients,
which falls back into the realm of the at-
tending thoracic surgeon.

1, as an anesthesiologist, enjoyed reading
this book.

Lisa M Weavind MBBCh

Department ot Anesthesiology and

Critical Care

University of Texas

MD Anderson Cancer Center

Houston. Texas

CORRECTION

In the letter "Aerosols and the Profession of Respiratory Care:

Leading the Way Out of the Fog" by Kenneth E Noblett (Respir Care

2001 :46[3]:275-276) the location of the author is in error. He is from

Evansville, Indiana — not Illinois.

496

Respiratory Care • Ma^i 200 1 Vol 46 No 5

The American Association for Respiratory Care
Clinical Practice (>uiclelines

• |{|(mkI (ias Analysis and Hcni»»\inu(r>: 2001 Ke\isiun iV I pdate
. |{(wlv l'k'tlnsniojira|)li>: 2(M(I Kcxision iV I |)<la(i'

» Kveicisi' H'stinj: lor Kxaluation of MxpoM'niia and/or Ik-saturation: 2(M)I Ki>isi()n
<!(: I pdate

• Mi'tliacholine Challenge Testin}': 2(HH Revision & Ipdate

• Static Liuifj Volume: 2(K)I Revision & I pdate

RcspirCair 21)01 ;46(5):498-539
Previously Published Guidelines:

• Remin;il iililic Ijuldtracheal Tube

• Sinulc-Hivalh taihon Mormxidc l^it'fusing Capacity. 1999 Update

• Suctioning oi itie Patient in tlie Home

• Selection of Device, Administration oi BroiiLhodilatoi, ami
Hvalualiiin of Response to Tlierapy in MeeharnL-all_\ Venlilaleii
Patients

Kcspir Can- 1 999:44( I l:N5- 1 1 J

•Spirometry. 1996 Update

• Selection ol an Oxygen Delivery Device for Neonatal and Pediatric
Patients

• Selection of a Device lor Deli\ery of Aerosol to ihe l.ung
Parenclnma

• Training the Health-Care Professional for the Role of Patient and
Caregi\er Educator

• Pro\ iding Patient and Caregiver Training

Rcspir Care 1996:4l(7):629-663

• Assessing Response to Bronchodilator Therapy at Point of Care

• Discharge Planning for the Respiratory Care Patient

• Long-Tenn ln\asi\e Mechanical Ventilation in the Home

• Capnographv /Capnometry during Mechanical Ventilation

• Selection of an Aerosol Delivery De\ice for Neonatal and Pediatric
Patients

• Poly.somnography

Respir Care 1995:401 12): 1300- I.W

• Defibrillation during Resuscitation

• Management of A\irvvay Emergencies

• Infant/Tixldler Pulmonarv' Function Tests

Respir Care 1995;40(7):744-76S

• Metabolic Measurement Using Indirect Calorimetiy during
Mechanical Ventilation

• Transcutaneous Blood Gas Monitoring for Nconalal and Pediatric
Patients

• Capillars BI(hxI Gas Sampling for Neonatal anil Pcilialric Patients

• Bod\ Plelhvsmograpin

Respir Care 1 994: 39( 1 2): 1 1 70- 1 1 90

Ri:si'iRATORV Care • Ma^ 2001 Vol 46 No 5

• Ventilator Circuit Changes

• Delivcrv of Aerosols to the Upper Airvvay

• Neonatal Time-Triggered. Pressure-Limited. Time Cycled
Mechanical Ventilation

• Application of Continuous Positi\e Airway Pressure to Neonates
via Nasal Prongs or Nasopharyngeal Tube

• Surfactant Replacement Therapy

• Sialic Lung Volumes

Respir Care l994:39{S):797-836

• Transpoii ol the Mechanically Ventilated Patient

• Fiberoptic Bronchoscopy Assisting

• Resuscitation in Acute Care Hospitals

• liucniiillcnt Positive Pressure Breathing

• Bland Aerosol Administration

Rc'.i'ir Care 1993:38(1 1 ): 1 1 69-1 2(X)

• Directed Cough

• Endotracheal Suctioning of Mechanically Ventilated Adults
and Children with Artificial Airways

• In-Vitro pH and Blood Gas Analysis and Hemoximetry

• Single-Breath Carbon Monoxide Diffusing Capacity

• Use of Positive Airway Pressure Adjuncts to Bronchial
Hygiene Therapy

Respir Care 1993:3S(5):49?-52I

• Patient-Ventilator System Checks

• llumidillcation during Mechanical Ventilation

• Selection of Aerosol Delivery Device

• Nasotracheal Suctioning

• Bronchial Provocation

• Exercise Testing for E\ aluation of Hyiioxemia and/or Desaturation

• Artenal BIochI Gas Sampling

• Oxygen Therapy in the Home or lixlended Care Facility

Respir Care l992:37(8):882-922

' Incentive Spirometry

• Pulse Oximetry

• Oxygen Therapy in the Acute Care Hospital

• Spiromeliy

• Postural Drainage Therapy

Respir Care 1991:361 12): 1398-1426

497

AARC Guideline: Blood Gas Analysis and Hemoximetry: 2001 Revision & Update

AARC Clinical Practice Guideline

Blood Gas Analysis and Hemoximetry: 2001 Revision & Update

B(;A l.OPROCKDURK:

BliHtd gas and pi I analysis and hemoximetry (ie,
CO-o\imetiy )

BG A 2.0 DESCRIPTION:

Analysis of arterial and/or mixed venous blood pro-
vides information concerning the oxygenation, ven-
tilatory, and acid-base status of the subject from
v\hom the specimen was obtained. Analysis of sam-
ples from other sources (ie, capillary, peripheral ve-
nous, umbilical venous samples, and pH measured
from other body fluids) may provide limited infor-
mation The variables most generally measured are
the partial pressures for carbon dioxide and oxygen
(Pco-, and Pqt). and hydrogen ion concentration
(pH). Additional clinically useful variables are the
concentration of total hemoglobin (tHb), oxyhe-
moglobin saturation (02Hb), and saturations of the
dyshemoglobins (carboxyhemoglobin, or COHb,
and methemoglobin. or metHb).'"^ and other calcu-
lated or derived values such as plasma bicarbonate
and base excess/deficit.

EGA 3.0 SETTING:

Analysis should be performed by trained individu-
als"*^ in a variety of settings including, but not limit-
ed to:

3.1 hospital laboratories,

3.2 hospital emergency areas,

3.3 patient-care areas,

3.4 clinic laboratories,

3.5 laboratories in physicians" offices.^

B(;A 4.0 INDICATIONS:

Indications for blood gas and pH analysis and

hemoximetry include:

4.1 the need to evaluate the adequacy of a pa-
tient's ventilatory (Paco;)- acid-base (pH and
PaCO:). and/or oxygenation (P-,(): and 02Hb)
status, the oxygen-carrying capacity (PaO:-

OiHb, tHb, and dyshemoglobin saturations)'-''
and intrapulmonary shunt (Qsp/Qt);

4.2 the need to quantitate the response to thera-
peutic interventit)n (eg. supplemental oxygen
administration, mechanical ventilation) and/or
diagnostic evaluation (eg, exercise desatura-
tion);' '

4.3 the need to monitor severity and progres-
sion of documented disease processes.'-

BGA 5.0 CONTRAINDICATIONS:

Contraindications to performing pH-blood gas
analysis and hemoximetry include:

5.1 an improperly functioning analyzer:

5.2 an analyzer that has not had functional sta-
tus validated by analysis of commercially pre-
pared quality control products or tonometered
whole blood'^*'""' or has not been validated
through participation in a proficiency testing
program(s ):'■**• '"'^

5.3 a specimen that has not been properly anti-
coagulated:"''^ '"•

5.4 a specimen containing visible air bubbles:'-'*

5.5 a specimen stored in a plastic syringe at
room temperature for longer than 30 minutes,
stored at room temperature for longer than 5
minutes for a shunt study, or stored at room
temperature in the presence of an elevated
leukocyte or platelet count (PaO: in samples
drawn from subjects with very high leukocyte
counts can decrease rapidly. Immediate chilling
and analysis is necessary).'* '"■-"

5.6 an incomplete requisition that precludes ad-
equate interpretation and documentation of re-
sults and for which attempts to obtain addition-
al information ha\e been unsuccessful. Requi-
sitions should contain

5.6.1 patient's name or other unique iden-
tifier, such as medical record number;
birth date or age, date and time of sam-
pling;

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5.6.2 location ot patient:

5.6.3 nann.- oi rccjucsting physician or aii-
tlnni/cil iiuii\ itlual;

5.6.4 clinical imiication and tests to he
pertbrmcd;

5.6.5 sample souice (arterial line, central
\eiuHis catheter, peripheral artcr\ i;

5.6.6 respiratory rate and lor the patient
on supplemental oxygen fractional con-
centration of inspired oxygen (FioO or
oxygen How;

5.6.7 ventilator settings for mechanically
\enlilated patients (tidal \olimie. respira-
tory rate. Hioj. mode);

5.6.8 signature of person who obtained
sample.'*''

It may also be useful to note body temperature,
activity level, and working diagnosis. Test rec|-
uishuni should be electronically generated or
handu ritten and must be signed by the person
ordering the test. Oral requests must be sup-
ported by written authorization within 30 days.''
5.7 an inadequately labeled specimen lacking
the patient's full name or other unique identifier
(eg. medical record number), date, and time of
sampling.'''

BGA 6.0 HAZARDS/COMPLICATIONS:

Possible hazards or complications include:

6.1 infection of specimen handler from blood ciir-
rying the human immunodeficiency \ ims. or HIV.
hepatitis B, oilier blood-borne pathogens:"'^"-'

6.2 inappropriate patient medical treatment
based on improperly analyzed blood specimen
or from analysis of an unacceptable specimen
or from incorrect reporting of results.

BCA 7.0 LIMITATIONS OF PROCEDURE/
VALIDATION OF RESULTS:

7.1 Limitations of technique or methodology
can limit value of the procedure. Erroneous re-
sults can arise froni

7.1.1 sample clotting due to improper an-
ticoagulation or improper mixing;'-'--

7.1.2 sample contamination by

7.1.2.1 air.

7.1.2.2 improper anticoagulant and/or
improper anticoagulant concentration.

7.1.2.3 saline or other fluids (specimen
obtained via an indwelling calheler).

7.1.2.4 inadvertent sampling of sys-
temic venous blood:

7.1.3 deterioration or distortion of vari-
ables to be measured resulting from

7. 1. 3. 1 delay in sample analysis (Sec-
tion ,s..^):

7.1.3.2 inappropriate collection and
handling (Accurate total hernoglobin
concentration measurement depends
on hoiiKJgeneous mixture of specimen,
appropriate anticoagulant concentra-
tion and specimen-size ratio, and ab-
sence of contamination of specimen by
analyzer solutions or calibration gases.
The concentration measured may also
be dependent on the method incorpo-
rated b\ the specific analyzer.'^):

7.1.3.3 incomplete clearance of analyz-
er calibration gases and previous waste
or Hushing solulion(s);^

7.1.4 Hyperlipidemia causes problems
with analyzer membranes and may affect
CO-oximetry.''

7.1.5 Appropriate sample size is deter-
mined by the type of anticoagulant' - '^ and
the sample requirements of the
analyzer(s).'' Attempts should be made to
keep sample sizes as small as is technical-
ly feasible to limit blood loss, particularly
in neonates.''

7.1.6 Some calculated values may be in
error (eg. calculated SaO: may not reflect
OiHb in the presence of COHb and/or
metHb and with changes in 2..^ DPG con-
centration).

7.1.7 Arteriali/ed capillary samples may
be adequate to assess acid-base disorders
but may not adequately reflect patient
oxygenation.

7.1.8 The laboratory must have a defined
procedure for temperature correction of
the measured results. Errors in the mea-
surement of the patient's temperature may
cause erroneous temperature-con'ected re-
sults. If temperature-adjusted results are
reported, the report should be clearly la-
beled as such, and the measured results at
37 ° C must also be reported.'^

7.2 Results of analysis can be considered valid if
7.2.1 analytic procedure conforms to rec-

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AARC GuiDKLiNE: BLOOD Gas Analysis and Hemoximi-try: 2001 Revision & Update

ommended. established guidelines'-'' and
follows manufacturer's recommenda-
tions;

7.2.2 results of pH-blood gas analysis fall
within the calibration range of the analyz-
er(s) and quality control product ranges.''
If a result outside of the usual calibration
range is obtained (eg, PaO: measured as
250 torr. hut analyzer calibrated to 140
torr), the analyzer should be recalibrated
to accommodate this unusual value (using
"calibration override" function and high-
er 100'/< -oxygen standard gas).

7.2.3 laboratory procedures and personnel
are in compliance with quality control and
recognized proficiency testing pro-
grams."''''^''

7.3 If questionable results are obtained and are
consistent with specimen contamination:

7.3.1 the labeling of the blood sample
container should be rechecked for pa-
tient's full name, medical record number
(patient identifier), date and time of ac-
quisition, and measured Fio: (or supple-
mental oxygen liter flow);'*-'

7.3.2 the residual specimen should be rean-
alyzed (preferably on a separate analyzer);

7.3.3 an additional sample should be ob-

tained if the discrepancy cannot be re-
solved;

7.3.4 results of analysis of discarded sam-
ples should be logged with reason for dis-
carding.''

BGA 8.0 ASSESSMENT OF NEED:

The presence of a valid indication (BGA 4.0) in the
subject to be tested supports the need for sampling
and analysis.

BGA 9.0 ASSESSMENT OF QUALITY OF
TEST AND VALIDITY OF RESULTS:

The consensus of the committee is that all diag-
nostic procedures should follow the quality
model described in the NCCLS GP26 A Quality
System Model for Health Care.-' (Fig. 1 ) The
document describes a laboratory path of work-
flow model that incorporates all the steps of the
procedure. This process begins with patient as-
sessment and the generation of a clinical indica-
tion for testing through the application of the test
results to patient care. The quality system essen-
tials defined for all healthcare services provide
the framework for managing the path of work-
flow. A continuation of this model for respiratory
care services is further described in NCCLS
HS4-A A Quality System Model for Respiratory

Laboratory Path of Workflow

Quality
System
Essentials

Organization
Personnel
Equipmenl
Purchasing/

Invenlory
Process

control
Documents/

Records
Occurence

management
Internal

assessment
Process

improvement
Service and
\ Satisfaction

Preanalvlical

Anahtical

Patient Test Specimen Specimen Specimen Testing Laborator>'
Assessment Request Collection Transpon Receipt Review Interpretation

Post- Infomialion N

Analytical Manageniinl s

Results Posl-test LabordtoT> Interpretation/

Report Specimen Information Consultation

Management Testing System

Quality system essentials
apply to all operations
in the path of workflow

Fig. 1 . StruclLire tor a Quality .System Model for a Laboratory Ser\ ice (From Reference 23. w ith permission)

500

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Care.-"' In both qiuililv huhIcIs the ixiticni is the
central focus.

9.1 (Icncial consideration iiiclLicie:

9.1.1 AspartolaiiN qiiahly assLiraiice pro-
gram, indicators must be developed to
monitor areas addressed in the path of"
woiktlow.

9.1.2 l-.icli laboratory siioiikl siaiulardize
procedures and demonstrate inteitechnol-
ogist reliability. Test results can be con-
sidered valid only if they are derived ac-
cording to and conform to established lab-
oratory i.|ualil\ control, quality assurance,
and inonilormg protocols.

9.1.3 Documentation of results, therapeu-
tic intervention (or lack of) and/or clinical
decisions based on testing should be
placed in the patient's medical record.

9.1.4 The mode of ventilation, the oxygen
concentration, and the oxygen delivery
device and the results of the pretest as-
sessment should be documented.

9.1.5 Report of test results should contain
a statement by the technician performing
the test regarding test quality (including
patient understanding of directions and
effort expended) and. if appropriate,
which recommendations were not met.

9.1.6 Test results should be interpreted by
a physician, taking into consideration the
clinical question to be answered.

9.1.7 Personnel who do not meet annual
competency requirements or whose com-
petency is deemed unacceptable as docu-
mented in an occurrence report should not
be allowed to participate, until they have
received remedial instruction and have
been re-evaluated.

9.1.8 There must be evidence of active re-
view of quality control, proficiency test-
ing, and physician alert, or "panic" values,
on a level commensurate with the number
of tests performed

9.2 Blood gas-pH analysis and hemoximetry
are beneficial only if no preanalytical error has
occurred.''

9.3 Considerations related to equipment quality
control and control materials:

9.3.1 For internal-equipment quality con-
trol usin" ct)mmercial ct)nlix)ls:

9.3.1.2 Rstablish the mean and sian-

danl deviation (SHi inr each con-
stituent (ie, pH, F( (, . \\, ) in each level
for a new lot number of commercial
quality control material prior to expira-
tion of the old lot number The labora-
tory director or designee should deter-
mine the acceptable range lor quality
control results based on statistically
relevant or medical-needs criteria.

9.3.1.3 The frequency of each control
run and number of levels is dependent
on regulatory requirements and manu-
facturer's recommendations beyond a
minimum ol I level every 8 hours and
2 levels each day that the instrument is
in operation.''

9.3.1.4 Quality control results outside
predefined acceptability limits should
trigger ei|ui[iment troubleshooting.
Quality contri)! must be verified to be
"in control" prior to analysis of speci-
mens. Appropriate documentation of
actions taken and results of veritlcation
are required.

9.3.1.5 Duplicate specimen analysis
(ie. twice on one instrument or once on
two instruments) may also be per-
formed on a regular basis as an addi-
tional method of quality control. Dupli-
cate analysis of the same analytes on
different nu)dels of equipment is gener-
ally required by accrediting agencies.

9.3.1.6 Tonometry is the reference pro-
cedure to establish accuracy for blood
Po: and Pco:- If issues of true accuracy
arise, tonometry should be a\ail-
able.5-5

9.3.1.7 Electronic quality control mon-
itors onl\ the equipment performance.
The use of nonelectronic controls at pe-
riodic intervals should also be em-
ployed to evaluate the testing process.'

9.3.1.8 Record keeping. Summarize all
quality control data for a specified lot
number. Maintain and generate reports
according to regulatory and institution-
al policy.

9.3.2 External quality control or profi-
ciency testing'' considerations:

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9.3.2.1 Proficiency testing is required
by the Clinical Laboratory Amend-
ments t)l 14SS (CLIA'SS)" tor each reg-
ulated analyte. Specimens ol unknown
values from an external source are to
be analyzed a minimum of 3 times a
year.

9.3.2.2 Proficiency-testing materials
should be obtained from an approved
source to meet regulatory require-
ments.

9.3.2.3 The proficiency testing survey
rept)rt should be carefully re\'iewed by
the medical director and laboratory su-
pervisor. If the results are suboptimal,
the medical director and supervisor
should promptly review their equip-
ment, procedures, and materials to as-
certain the cause of the poor perfor-
mance.-^

9.3.3 With new equipment installation:-"'

9.3.3.1 CLIA '88 requires the evalua-
tion of equipment accuracy and impre-
cision prior to analysis of patient sam-
ples.^

9.3.3.2 Tonometry is the reference
method for establishing accuracy for
PaO: and PaCO:-"^ tiut unless the entire
tonometry process is of the highest
quality, it. too. can ha\e errors.

9.3.3.3 When an existing instrument is
replaced, duplicate analysis must be
performed to compare the new instru-
ment to the existing instrument.

9.3.4 Calibration verification-^

9.3.4.1 Calibration verification is per-
formed prior to initial use and at 6-
month intervals. Calibration verifica-
tion is completed by analyzing a mini-
mum of ?i levels of control material to
verify the measuring range of the ana-
lyzer. A fourth level should be consid-
ered if samples with high O2 levels are
analyzed on the instrument.

9.3.4.2 l-requency of calibration verifi-
cation may vary according to regulato-
ry agencies under which the laboratory
is accredited or licensed |ie. College of
American Pathologists (CAP).
CLIA"88 or Joint Commission on Ac-

creditation of Healthcare Organizations
(JCAHO)I.

9.4 Testing (analytical phase) is carried out ac-
cording to an established proven protocol, con-
I'orming to manufacturer recommendations;''''
The following aspects of analysis should be mon-
itored and corrective action taken as indicated:

9.4.1 detection of presence of air bubbles
or clots in specimen, with evacuation
prior to mixing and sealing of syringe;''* '^

9.4.2 assurance that an uninterrupted (ie,
solid or continuous) sample is aspirated
(or injected) into analyzer and that all of
the electrodes are covered by the sample
(confirmed by direct viewing of sample
chamber if possible;"

9.4.3 assurance that 8-hour quality control
and calibration procedures have been
completed and that instrumentation is
functioning properly prior to patient sam-
ple analysis;^*'**

9.4.4 assurance that specimen was proper-
ly labeled, stored, and analyzed within an
acceptable period of time^ ■" (see Section
5.5).

9.5 Post-testing (post-analytical phase) The re-
sults should validate or contradict the patient's
clinical condition (ie, the basis for ordering the
test),-*-'

9.5.1 Documentation of results, therapeu-
tic intervention (or lack of), and/or clini-
cal decisions based upon the pH-blood
gas measurements should be available in
the patient's medical record and/or be oth-
erwise readily accessible (eg, at the test-
ing area) for at least 2 years.*

9.5.2 Reference intervals and 'critical \ al-
ues' must be determined for each analyte
prior to sample analysis. If the reference
interval is determined by transference, the
interval should be validated. Defining and
determining reference intervals is de-
scribed in NCCLS document C24-A2.28

BGA 10.0 RESOURCES:
Federal regulations," stipulate that requirements
relative to personnel (levels of education and train-
ing), documentation pmcedures and equipment be
lulfilled. Blood gas mstrumentatit>n is classilied as
being either moderately or highly complex.
Persons performing blood gas analysis should be

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A ARC Cil IDI.I.IM.; IJl.OODCiA.S ANALYSIS ANU I ll.M( JXIMI, I m . JOOl KlAISKJN i: I I'lJATI;

con\ois;iiil willi ;i|i|ilii.ablc Icilcr;!! ivuulalions
(CLIA'SS)" aiul .ippm|iiiak'l\ i|iialiticil.

10.1 Kocoiinik'iklL'il I'liLiipiiK'nl;

10. 1.1 AuUimatcd or' scmiauloiiialcil pll-
bloi)i.l gas analy/.er wilh iclaicil (.alibia-
tioii gases, electrodes, iiiembiaiies, elec-
liol\ tes, reagents, and accessories.^''-''

10.1.2 li\e\l. nuilliplc \\a\elcngth spec-
tro|iholonieler i hcinoxiincler or CO-
t)\inieler) or other device lor determining
total hemoglobin and its components.

10.1.3 Protective eye wear as necessary
ant! outer wear, protective gloves, impen-
etrable needle container, lace mask and/or
face-shield.-''

10.1.4 r)iiality control and proficiency
tcstnig materials.

10.2 Personnel:

The following recommendations are for tests of
moderate complexity, as designated by CLIA
"88.*' Persons at either of the levels described
should pcrlorm jiFf-blood gas analysis under
the direction and responsibility of a laboratory
director and technical consultant (may be the
same individual) who possess at least a bac-
calaureate degree and who have specific train-
ing in blood gas analysis and interpretation.''
10.2.1 Level 1: Personnel should be
specifically trained in pH-blood gas anal-
ysis, oxygen delivery devices, and related
equipment, record keeping, and hazards
and sources of specimen and handler con-
tamination(s) associated with sampling
and analysis. Such persons should be, at
minimum, high school graduates (or
equivalent) with strong backgrounds in
mathematics, and preferably with one or
more years of college courses in the phys-
ical and biological sciences.'" Such per-
sons must have documented training and
demonstrated proficiency in pH-blood gas
analysis, preventive maintenance, trou-
bleshooting, instrument calibration, and
awareness of the factors that influence test
results, and the skills required to verify
the validity of test results through the
evaluation of quality-control sample \al-
ues, prior to analyzing patient specimens
and reporting results'' '" Performance of

|il I blood gas analysis must be supervised
b\ a l.e\el-ll technologist.
10.2.2 Level II: l.evel-11 personial super-
vise l.e\el-l ix'isonnel aiul arc hcallli care
professionals specilically trained (with
proven, documented proficiency) in all
aspects ol blood gas analysis and
hemoximelry:

10.2.2.1 quality control, quality assur-
ance, and |irol'iciency testing;

10.2.2.2 operation and Inniiations. in-
cluding instrument troubleshooting and
appropriate corrective measures.

10.2.2.3 Ix'vel-11 personnel should be
cognizant ol \ ai ious ineans for speci-
men collection and the causes ant! im-
pact of preanalytical and instrument
error(s).

10.2.2.4 Level-II personnel should be
trained in patient assessment, acid-base
and oxygenation disorders, and diag-
nostic and therapeutic alternatives. A
baccalaureate, or higher, degree in the
sciences or substantial experience in
pulmonary function technology is pre-
ferred. Although, 2 years of college in
biological sciences and mathematics,
plus 2 years of training and experience,
or equivalent may be substituted for
personnel supervising arterial pH-
blood gas analysis."' A recognized cre-
dential (MT. MLT, CRT, RRT, CPFT,
RPFT) is strongly recommended.''

BGA 11.0 MONLrORINC:

Monitoring of personnel, sample handling, ami ana-
lyzer performance to assure proper handling, analy-
sis, and reporting should be ongoing, during the
process.

B(,A 12.0FRKQLKNCV:

Frequency of execution ot preicedurcs depcnels
upon the sample load of the laborators and the re-
quirements of agencies that specify quality control
maneuvers.

BGA 13.0 INFKCTION C ONTROL:

13.1 The staff, supers isors. and physician-di-
rectors associated w ith the pulmonary laboralo-

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AARC CiuiDLLiNb: Bi.cKJu Gas Analysis and Hhmoximi-try; 2001 Ri:\ isiu.n & Update

ry should be conversant with "Guideline for
Isolation Precautions in Hospitals" made by the
Centers lor Disease Control and the Hospital
Infection Control Practices Ad\ isorv Commit-
tee (HICPAC)." and develop and implement
policies and procedures for the laboratory that
comply with its recommendations for Standard
Precautions and Transmission-Based Precau-
tions.

13.2. The laboratory's manager and its medical
director should maintain communication and
cooperation with the institution's infection
control service and the personnel health ser-
vice to help assure consistency and thorough-
ness in complying with the institution's poli-
cies related to immunizations, post-exposure
prophylaxis, and job- and community-related
illnesses and exposures. '-
13.3 Primary considerations include

13.3.1 adequate handwashing, '''

13.3.2 provision of prescribed ventilation
with adequate air exchanges,'^

13.3.3 careful handling and thorough
cleaning and processing of equipment."

13.3.4 the exercise of particular care in
scheduling and interfacing with the pa-
tient in whom a diagnosis has not been es-

tablished

.< I M

BGA 14.0 AGE-SPECIFIC ISSUES:

This document applies to samples from neonatal,
pediatric, adult, and geriatric populations.

Pulmonary Function Testing Clinical Practice
Guidelines Committee (The priiuipal uiilhor i\ list-
ed first):
Susan Blonshine BS KKT RPFT, Mason MI

Catherine M Foss BS RRT RPFT. Ann Arbor Ml
Curl Mottram BA RRT RPFT Chair. Rochester MN
Greiin Riippel MEd RRT RPFT. St Louis MO
Jack Waniier MS RRT RPFT. Lene.xa KS

The current Pulmonary Function Clinical Practice
Guidelines Committee updated an earlier version
(CPG: Sampling for arterial blood gas analysis.
RespirCare 1992:37(8):9I3-917) and gratefully ac-
knowledges the contributions of those individuals
who provided input to that earlier version: Robeil
Brown, Michael Kochansky. and Kc\in Shrake.

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qualifications. American Thoracic Society Position Paper.
ATS News; November 1982.

3 1. Garner JS. Hospital Infection Control Practices Advisory
Committee, Centers for Disease Control and Prevention.
Guideline for isolation precautions in hospitals. Am J Infect
Control I996;24( 1 ):24-31. or http//vv\vw. apic.org/html/
resc/gdisolat.html.

32. Centers for Disease Control and Prevention. Hospital Infec-
tion Control Practices Advisory Committee. Guideline for
infection control in health care personnel. 1998. Am J In-
fect Control 1998:26:269-354 or Infect Control Hosp Epi-
demiol 1998;19(6):407-463.

33. Larson EL. APIC guideline for handwashing and hand anti-
sepsis in health care settings. Am J Infect Control
1995;23(4):25l-269.

34. Centers for Disease Control & Prevention. Guidelines for
preventing the transmission of Mycobacterium tuberculosis
in health-care facilities. 1994. MMWR 1994;43(RR13): 1-
32 or Federal Register 1994;59(208):54242-54303 or
http://aepo-xd\ -www .epo.cdc.gov/wonder/prevguid/
m0035909/m00359()9.htm

Interested persons may pliDlocop) these Ciiiidelines tor noneniniiiercial purposes of scientific
or educational advancement. Plea.se credit AARC and RESPIRATORY CARE Journal.

RlspiRATORV Cari: • Ma'i- :()()I Vol 46 No 5

505

AARC Ciiinri INI : Boiiv PiHTtivsMonRAPnv: 2001 Ki vision & Update

AARC Clinical Practice Guideline

Body Plethysmography; 2001 Revision & Update

BP i.oprocp:diirk:

Body plethysmography for determination of thoracic-
gas volume ( VTG) anil airways resistance (R.iw)-

BP 2.0 DKSCRIPTION/DEHNITION:

During body plethysmography, the subject is en-
closed in a chamber equipped to measure pressure,
tlow, or vt)lume changes. The most common mea-
surements made using the body plethysmograph are
VTG and Rav,-'" Airways conductance (G;,u) is also
commonly calculated as the reciprocal of R^v Spe-
cific airways conductance (ie. conductance/unit of
lung \t)lume) is routinely reported as sGaw Other
tests thai can be administered in the body plethys-
mograph include spirometry, bronchial challenge,
diffusing capacity (Dlco)- single-breath nitrogen
(N:). multiple-breath N: washout, pulmonary com-
pliance, and occlusion pressure. These will not be
discussed as part of this guideline. Some have been
previously addressed.-^"^

2.1 VTG is expressed in liters (BTPS. or body
temperature and pressure saturated) and is the
volume of gas in the lung when the mouth shut-
ter is closed. In plethysmographic studies, it is
commonly used to represent the functional
residual capacity (FRC).

2.2 Raw is reported in cm HiO/L/s (ie, cm H2O •
L-'-s-').

2.3 sGaw is reported in L/s/cm H2O (ie, L ■ s' ■
cm HiO') and is the reciprocal of the Raw
(l/Rau) divided by the lung volume at which
the resistance measurement is made.

BP 3.0 SETTINGS:

3.1 Pulmonary function laboratories

3.2 Cardiopulmonary laboratories

3.3 Clinics and physician's offices

BP 4.() INDICATIONS:

Body plethysmographic determination of VTG,
Raw. and sGaw may be indicated:

4.1 lor diagnosis of restrictive lung disease;

4.2 for measurement of lung volumes to distin-
guish between restrictive and obstructive pro-
cesses;

4.3 for evaluation of obstructive lung diseases,
such as bullous emphysema and cystic fibrosis,
which may produce artifactually low results if
measured by helium dilution or N2 washout.^
With simultaneously determined volumes, an
index of trapped gas (ie, FRCpieihs sinograph/
FRChc dilution) can be established.''

4.4 for measurement of lung volumes when
multiple repeated trials are required or when
the subject is unable to perform multibreath
tests;"^

4.5 for evaluation of resistance to airflow;'"

4.6 for determination of the response to bron-
chodilators, as reflected by changes in Raw-
sGaw, andVTG;"

4.7 for determination of bronchial hyperreac-
tivity in response to methacholine, histamine,
or isocapnic hyperventilation as reflected by
changes in VTG, Raw. and sGaw;'""'"^

4.8 for following the course of disease and re-
sponse to treatment,

BP 5.0 CONTRAINDICATIONS:

Relative contraindications to body plethysmogra-
phy are:

5.1 mental confusion, nuiscular incoordination,
body casts, or other conditions that pre\ ent the
subject from entering the plethysmograph cabi-
net or adequately performing the required ma-
neuvers (ie, panting against a closed shutter);

5.2 claustrophobia that ma> be aggra\ated by
entering the plethysmograph cabinet:

5.3 presence of devices or other conditions,
such as continuous intravenous infusions with
pumps or other equipment that will not fit into
the plcth\ sinograph, that should not be discon-
liiuicd. or that might mlerferc with pressure

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changes (eg. chest tube. transt!ache;il Oi
catheter, or rupturcil oaalruin):
5.4 conimiiDLis o\\L;L'n therapy that shoiikl not
be icniporarils disLiiniiiua'tl.

BP 6.0 H AZARI)S/C OMPLK ATIONS:

6.1 VTG and Raw measurements require the

suhjecl in pant against a closed shutter: improp-
er panting technique ma\ result in e\cessi\e in-
trathoracic pressures.

6.2 Prolonged confinement in the plethysmo-
graph chamber could result in hypercapnia or
hypoxia: ho\\e\er. because ot the limited
length ol the test and the tad thai the plethys-
mograph must be vented periodically, this is an
uncommon occurrence.

6.3 Transmission of infection is possible \ia
improperly cleaned equipment (ie. mouth-
pieces) or as a consequence of the inac.i\cilcnt
spread of droplet nuclei or both fluids (paticnl-
to-patient or patient-to-technologist).

BP 7.(1 LIMITATIONS OF METHODOLOCJV/
VALID.4TION OF RESULTS:

Limitations of the body plethysmograph in mea-
surement of VTG. Rju. and sG;,^ include but are
not limited to:

7.1 overestimation of VTG in subjects with se-
vere obstruction or induced bronchospasm un-
less a slow 'panting" speed (ie. approximately 1
cycle/s) is maintained.'"" '^

7.2 Erroneous measurement of VTG. R;,«. t)r
sGaw due to improper panting technique. Ex-
cessive pressure fluctuations or signal drift dur-
ing panting may invalidate VTG, Raw. or
sG "*

7.3 Nonpanting measurements ha\e been sug-
gested for use HI children or others who have
difficulty mastering the panting maneuver.''*-"
Nonpanting maneuvers in plethysmographs
with built-in thermal leaks may invalidate VTG
or Rau measurements.- -'

7.4 Computer-determined slopes of either VTG
or R,iw tangents may be inaccurate. Many sys-
tems calculate the slopes using a best-fit regres-
sion analysis. This technique may produce
widely varying results if extraneous data points
are included (due to improper panting or exces-
sive signal drift). All slopes shoLiki be \isually
inspected and adjusted according to an estab-

lished laboratory procedure.-^-'

7.5 F-xcessive abdominal gas or panting tech-
niques that employ accessory muscles may in-
crease the measured VTG, due to compression
effects.--'

7.6 Plethysmography is a complex test. Careful
calibration of multiple transducers is required.
Attention to frequency response, thermal stabil-
ity, and leaks is necessary.-''

7.7 Choice and application of reference values
affect interpretation. Reference values for VTG
using plethysmographically determined lung
volumes are not widely available.

7.7.1 Make a tentative selection from
whatever published reference values are
available. The characteristics of the
healthy reference population should
match the study group with respect to age,
body size, gender, and race. The equip-
ment, techniques, and measurement con-
ditions should be similar.

7.7.2 Following selection of seemingly
appropriate reference \alues, compare
measurements obtained from a represen-
tative sample of healthy individuals (10-
20 subjects, over an appropriate age
range) to the predicted values obtained
from the selected reference values. If an
appreciable number of the sample fall out-
side of the normal range, more appropri-
ate reference values should be sought.
This procedure detects only relatively
gross differences between sample and ref-
erence populations.-^

BP 8.0 ASSESSMENT OF NEED:

8.1 .See Section 4.0 Indications.

8.2 Protocols may define the need for measure-
ment of lung volumes and airway resistance
measurements based on the results of previous-
ly performed tests (ie. spirometry, diffusing ca-
pacity) and the clinical question to be an-
swered.

BP 9.0 ASSESSMENT OF QL ALIT^ & \ ALI-
DATION OF RESILTS:

The consensus of the Committee is iluii .ill diagnos-
tic procedures should follow the quality model de-
scribed in the NCCLS GP26-A A Quality System
Model for Health Care.-" (Fig. 1 ) The diKument de-

Rr-spiR ATORY Carp • May 2001 Vf)i 46 No ."i

507

AARC Guideline: Body Plethysmography: 2001 Rivision & Update

scribes a laboratoi> path of workllow model that in-
corporates all the steps of the procedure. This pro-
cess begins with patient assessment and the genera-
tion of a clinical indication for testing through the
application ol the test results to patient care. The
quality system essentials defined for ail health care
services pro\ ide the framework for managing the
path of workflow. A continuation of this model for
respiratory care services is further described in
NCCLS HS4-A A Quality System Model for Res-
piratory Care.-^ In both quality models the patient is
the central focus.

9.1.3 Documentation of results, therapeutic
intervention (or lack of) and/or clinical de-
cisions based on the testing sht)uld be
placed in the patient's medical record.

9.1.4 The type of medications, dose, and
time taken prior to testing and the results
of the pretest assessment should be docu-
mented.

9.1.5 Report of test results should contain
a statement by the technician performing
the test regarding test quality (including
patient understanding of directions and ef-

Pulmonary Diagnostics Path of Worlvflow

Quality
System
Essentials

Organi/allun
Personnel
Eujuipment
Purchasing/

Inventor^'
Process

control
Documents/

Records
Occurence

management
Internal

assessment
Process

improvement
Service and

Satisfaction
S

Pretest

Patient Assessment
Test Request
Patient Preparation
Equipment Preparation

Testing Session

Patient Trainmg

Test Pertbrmance

Results Review and Selection

Patient Assessment for Further Testing

Information Management

Inlomiation System

Quality system essentials
apply to all operations
in the path of workflow

Post-test

Results Report
Interpretation
Clinical Consult

Fig. 1 . Structure for a Quality System Model for a Pulmonary Diagnostics Service (From Reference 27. with permission)

9.1 General consideration include:

9.1.1 As part of any quality assurance pro-
gram, indicators must be developed to
monitor areas addressed in the path of
workflow.

9.1.2 Each laboratory should standardize
procedures and demonstrate intertechnol-
ogist reliability. Test results can be con-
sidered valid only if they are derived ac-
cording to and conform to established lab-
oratory quality control, quality assurance,
and monitoring protocols.

fort expended) and, if appropriate, which
recommendations were not met.-''""

9.1.6 Test results should be interpreted by
a physician, taking into consideration the
clinical question to be answered.

508

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A ARC (li IDI 1 INI : IJoD"! I'l I iin s\i()(,K \l'in : 2001 Kl. vision <t ri'DAll-

boon ie-cv;ilii;itec!.

9.1.8 I'lieic iiuisi be evidence i)t active re-
view of t|iiality control, proticieney test-
ing, and piiysician alert, or 'panic' values,
on a level commensurate with the number
of tests iiertbrmed.

9.2 Calibration ami (.|uality control measiues
specific to equipment used in plethysmography
include:

9.2.1 Calibration at recommended Ire-
quencies, at any time accuracy is su.spect,
and when the equipment is moved to a
dillerenl location.

9.2.2 On a daily basis, calibrate volume,
mouth and box pressure.

9.2.3 At least monthly, manually calibrate
systems in addition to daily use of the au-
tocalibration system.

9.2.4 At least weekly, assess linearity of
nt)w-sensing device.

9.2.5 At least quarterly, perform airway
resistance with a known resistor and cal-
culate results. ^-

9.2.6 At least annually or at a frequency
established by the laboratory on the basis
of the tendency of the device to vary,
check volume with isothermal bottle. ''

9.2.7 At least monthly and at any time ac-
curacy is suspect, perform tests on stan-
dard subjects (biologic controls, or bio-
QC).""-

9.2.8 Test standard subjects more fre-
quently initially to establish statistical
variation for comparison.

9.2.9 It may be advantageous to perform
Bio-QC at weekly or semi-monthly inter-
vals.

9.3 Test Quality Assessment: Results are valid
if the equipment functions correctly and the
subject is able to perform acceptable and repro-
ducible maneuvers.

9.3.1 VTG maneuvers are acceptable

when:

9.3.1.1 the displayed or recorded trac-
ing indicates proper panting technique
(the loop generated against a closed
shutter should be closed or nearly so).
The patient should support his/her
cheeks with the hands to prevent pres-
sure changes induced bv the mouth. ^■'

This should be done without supporting
the elbow s or elc\ ating the shoulders.

9.3.1.2 Recorded pressure changes
should be within the calibrated pres-
sure range of each transducer (See Sec-
tion 10.1..^). The entire tracing should
be visible. Pressure changes that are
too large or too small may yield erro-
neous results.

9.3.1.3 Thermal eL|uililiruim sluiukl he
evident; tracings should not drift on the
display or recording. (This typically
takes 1-2 minutes.)

9.3.1.4 The panting frequency is ap-
pro.ximately 1 Hz. Nonpanting maneu-
vers may be acceptable if the plethys-
mograph system is specifically de-
signed to perform such maneuvers.'''-^'

9.4. R;,« and sG^^ maneuvers may be con-
sidered acceptable if:

9.4.1 they meet criteria given in Sec-
tions 9.3.1.1 through 9.3.1.3:

9.4.2 the open-shutter panting maneu-
ver shows a relatively closed kxip. par-
ticularly in the range of -t-()..'> to -0.5 L/s;

9.4.3 the panting frequency during seri-
al measurements in a given patient is
kept constant to aid in interpretation.
Consensus of the group suggests a
range of 90- 1 50 cycles per minute ( 1 .5-
2.5 Hz). Frequency should be held con-
stant for within-testing session compar-
isons (ie, pre- and post-bronchodilator
testing) and serial testing.

9.5 Test Results Reporting:
9.5.1 The reported VTG

9.5.1.1 should be averaged from a min-
imum of 3-5 separate, acceptable pant-
ing maneuvers;^^'^^

9.5.1.2 should be calculated using val-
ues that agree within yi of the mean
(widely varying v alues should be aver-
aged, and reported as variable);

9.5.1.3 should indicate whether the
thoracic volume vv as at FRC or at some
other level;

9.5.1.4 should be compared with other
lung volume determinations (He dilu-
tion. N2 washout) if such are being per-
formed;

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AARC GUIDF.l.lNF,: BODY Pl.ITHYSMOGRAPHY: 2001 REVISION & UPDATE

9.5.1.5 should be corrected lor paiicnl

vvcii;hl tor siMiie systems.
9.5.2 Lung Volumes including llie slow \ ilal
capacity (VC) maneuver and its subdivi-
sions inspiratory capacity ( IC) and expirato-
ry reser\c \olume (ERV) should be per-
tbmied iluring the same testing session. The
ERV, IC. aiul VC should be measured in
conjunction u itli each VTG trial before dis-
connecting from the measuring system. Add
tracing to illustrate correct performance.

9.5.2.1 The largest volume of VC or
FVC obtained should be used for cal-
culation of derived lung volumes (ie,
total lung capacity, or TLC. residual
\olume. or RV. and RV/TLC7r).

9.5.2.2 The mean \alues should be re-
ported for IC and ERV from acceptable
VTG maneuvers.

9.5.2.3 There are various methods to
calculate TLC. but by consensus the
Committee recommends use of:
TLC = mean FRC + mean IC*
*(Note: Mean IC should be close to the
largest IC)

RV = TLC- largest VC

9.6 The reported R,,^, and sCr^^

9.6.1 should be calculated from the ratio
of closed and open shutter tangents for
each maneuver.^** (Airway resistance and
lung volume are interdependent in a non-
linear fashion);

9.6.2 should be averaged from 3-5 separate,
acceptable nianeu\ers as calculated in 9.4;
reproducibility should be based on sGaw
and the suggested limit for variance is with-
in 10% of the mean; (eg. if the measured re-
sults are < 0. 1 7. accept ± ().() 1 or if the mea-
sured results are > 0.20. use ± 0.02)'''

9.6.3 should ha\e the open-shutter tangent
(V/Pu,\) measured between flows of -1-0.5
and -0.5 L/s. For loops that display hystere-
sis, the inspiratory limbs may be used;"*

9.6.4 should have the sG;,u calculated
using the VTG at which the shutter was
closed for each indi\idual maneu\er.-^

9.7 Report of lest results should contain a state-
ment by the technologist performing the test
concerning test quality and, if appropriate.
\\ hich recommendations were not met.

9.8 Reference equations; l:ach laboratory
should select reference e(.|uations appropriate
for the methods and the po|iulation tested. Ciuid-
ance for defining and determining reference in-
tervals is provided in American Thoracic Soci-
ety (ATS)'- and NCCLS^" documents.

9.9 Test quality monitoring; Plethysmography
results should be subject to ongoing review by
a supervisor, uith feedback to the technologist.
The monitoring should include visual nispec-
tion of the VTG and Raw loops and fitted lines.
Quality assurance (QA) and/or quality im-
provement (Ql) programs should be designed
to monitor the technologist both initially and on
an ongoing basis.

BP 10.0 RESOURCES:
10.1 Equipment:

10.1.1 Volume-measuring devices used in
the plethysmograph (ie, the pneumota-
chometer) should meet or exceed ATS
recommendations. A 3-L syringe should
be available for calibration."

10.1.2 Either pressure (constant volume) or
flow-type plethysmographs may be used.

10.1.3 Transducers in the plethysmograph
shoLild meet prescribed range specifica-
tions:"''

Mouth pressure: ±20 to 50 cm H2O
Box pressure: ±2 cm H^O (500-L box)
Flow; 0.2 to 1.5 L/s

10.1.4 Pressure and volumes signals
should be phase aligned up to 10 Hz.

10.1.5 A plenum or similar device that fa-
cilitates thermal equilibrium is recommend-
ed. Some plethysmographs utilize air con-
ditioning to maintain thermal equilibrium.

10.1.6 The plethysmograph cabinet
should be easy for the subject to enter and
exit. The door should preferably be opera-
ble from within the box. The cabinet
should be equipped with an intercom and
should provide adequate visibility for
both the technologist and the subject.

10.1.7 The plethysmograph system, if
compuleri/ed. should allow for technolo-
gist adjusinicnl of open- and closed-shut-
ter tangents.

lO.l.S Calibration dc\iccs should mcludc
(in addition to a 3-L syringe) 30-50 mL

510

Re.spiraiory Care • Ma'i 2001 Vol 46 No 5

AARL tiL IIM.UM.: Hum I'l.l.lin.SMUCKAI'in: 2001 Kl \ ISION ct I 'PDA II.

sine-u;i\e pimip (\ ariahle spcetl. used pri-
mal i Is tor Lalibialion ol pivssmv boxes),
walor inaiiomelci' ±20 cm ll;() (used lor
ealibralion ol the nuuilh |iressure Iraiis-
diicer). and lolaineler lo 1..^ I./s (used
for ealibralion of the pneumotaehomeler).
10.2 Personnel: Plethysmography shoiikl be
perforined uiuler the (.lireetioii ol a ph\sleian
trained in |iulmonar_\ liinetion testing. It may be
performed by teehnologisis who meet criteria
for either Level I or Level II. Plethysmographie
results ean be compromised if the test is per-
formed by inadei|uately trained personnel.

10.2.1 Level 1: The technologist pcrlorm-
ing plethysmography sht)uid be a high
schoi)l graduate or equivalent with a
demonstrated ability to perform spirome-
try and lung volume determinations.
Level 1 personnel should perform plethys-
mography only under the super\'isit)n of a
Level II technologist or a physician.

10.2.2 Level II: Personnel supervising
plethysmography should have formal ed-
ucation and training.'*' This may be part of
an accredited program in respiratory ther-
apy or pulmonary function technology or
2 years of college work in biological sci-
ences and mathematics. Level II person-
nel should also have 2 or more years ex-
perience performing spirometry, lung vol-
umes, and diffusing capacity tests.
Attainment of the credential of Certified
Pulmonary Function Technologist (CPFT)
or Registered Pulmonary Function Tech-
nologist (RPFT) is recommended.

BF. 11.0 PATIKNT MONITORING:

(See also Section '■).() Assessment of Quality)

11.1 Evaluate the patient's breathing pattern to
verify a stable FRC level.

11.2 Verify appropriate shutter-closure timing.

11.3 Gauge the level of understanding (of test in-
structions), effort, and cooperation by the sub-
ject.

BP 12.0 FREQUKNCY:

The frequency with which plethysmography is re-
peated should depend on the clinical iiucstion(s) to
be answered.
BP 13.0 INFECTION CONTROL:

13.1 The staff, supervisors, and physician-di-
rectors associated with the pulmonary laborato-
ry should be conversant with "Guideline for
Isolation Precautions in Hospitals"'- and devel-
op anil implement |iolicies and procedures for
the laboratory that comply with its recommen-
dations for Standard Precautions and Transmis-
sion -Baseil Precautions.

13.2 1 he laborator\s manager and its medical
director should maintain communication and
cooperation v\ ith the institution's infection con-
trol service and the personnel health service to
help assure consistency and thoroughness in
complying w ith the institution's policies related
to immunizations, post-exposure prophylaxis,
and job- and communit\-rclatcd illnesses and
exposures."

13.3 Primary considerations include adequate
handwashing.'''' provision of prescribed ventila-
tion with adequate air exchanges.^^ careful han-
dling and thorough cleaning and processing of
equipment.'"' and the exercise of particular care
in scheduling and interfacing w ith the patient in
whom a diagnosis has not been established.''^
Considerations specific for plethysmography
measurement inclutic:

13.3.1 The use of filters is neither recom-
mended nor discouraged. Filters may be
appropriate for use in systems that use
valves or manifolds on which deposition
of expired aerosol nuclei is likely.^"

13.3.2 If filters are used in gas-dilution
procedures, their volume should be sub-
tracted when FRC is calculated.

13.3.3 If fillers are used in the plethy sino-
graph system, the resistance of the filters
should be subtracted from the airv\ays re-
sistance calculation.

13.3.4 Nondisposable mouthpieces and
equipment pails that come into contact with
mucous membranes, sali\a. and expirate
should be cleaned and sterilized or subject-
ed to high-level disinfection between pa-
tients.""" GUnes should be wiirn when han-
dling pt)tentially contaminated equipment.

13.3.5 Flow sensors, \al\es, and tubing not
in direct ct)ntact with the patient should be
routinely disinfected according to the hos-
pital's infection control policy. Any equip-
ment surface that displays visible conden-
sation from expired gas should Iv disin-
fected or sterilized before it is reused.

13.3.6 Water-sealed spirometers should
be drained weekly and allow cd to dry.-^"

RtiSPiK.ATORV Caki. • Mav 2001 Vol 46 No 5

511

AARC Guideline: Body Pi itiiysmocrapiiy: 2001 Ri vision & UpnAxn

13.3.7 Closed circuit spiroiiictcrs, such as
those used for He-dilution HRC determi-
nations, should be Hushed at least 5 times
over their entire volume to facilitate clear-
ance of droplet nuclei. Open circuit sys-
tem need only have the portion of the cir-
cuit throuijh which rebreathing occurs de-
contaminated between patients.

14.0 AGE-SPKCIKIC ISSUES:

Test instructions should be pro\ ided and techniques
described in a manner that takes into ct)nsideiation
the learning ahiiits and communications skills of
the patient being .served.

14.1 Neonatal: This Guideline does not apply
to the neonatal population.

14.2 Pediatric: These procedures are appropri-
ate for children w ho can perform spirometry of
acceptable quality and can adequately follow
directions for plethysmographic testing.

14.3. Geriatric: These procedures are appropri-
ate for members of the geriatric population who
can perform spirometry of acceptable quality
and adequately follow directions for plethys-
mographic testing.

Cardiopulmonary Diagnostics Guidelines Com-
mittee (The principal author is listed first ):
Susan Blonshine BS RPFT RRT, Mason MI

Catherine Foss BS RRT RPFT. Ann Arbor MI
CarlMottram BA RRT RPFT. Chair Rochester MN
Gregg Ruppel MFd RRT RPFT. St Louis MO
.lack WangerMBA RRT RPFT Lcncxa KS

The current Pulmonary Function Clinical Practice
Guidelines Committee updated an earlier version
(Body plethysmography. Respir Care 1994:39
(12):l 184-1 190) and wishes to acknowledge those
individuals who provided input to that earlier ver-
sion: Robert Brown. Michael Decker, and Kevin
Shrake.

REFERENCES

1. DuBois AB. Botclho SY. Bedell GN. Marshal R. Coniroe
JH. A rapid plethysmographic method for measuring tho-
racic gas volume: a comparison with nitrogen washout
nieth<Kl lor measuring functional residual capacit\ in nor-
mal subjects. J Clin Invest 1956:.\'S;322.

2. DuBois AB, Botelho SY. Comroe JH. A new method for

measuring airway resistance in man using a body plethys-
mograph: values in normal subjects and in patients with

respiratory disease. J Clin Invest 19.'i6;.3.S:.327.

3. American Association for Respirators Care. Clinical Prac-
tice Guideline: Spiromolr). 1 '>')(> update. Respir Care
l9%:47(7):629-6.%.

4. American Association for Respiratory Care. Clinical Prac-
tice Guideline: Bronchial provocation: 2001 revision & up-
date. Re.spirCare 2001:46(5):506-5I3.

5. American Association for Respiratory Care. Clinical Prac-
tice Guideline: Single-breath carbon monoxide diffusing
capacity. 1999 update. Respir Care l999:44(.';i:.S.^9-.S46.

6. American Association for Respiratory Care. Clinical Prac-
tice Guideline: Static lung voluines: 2001 revision & up-
date. Respir Care 2001 :46(5):53 1-539.

7. Ferris BG. Epidemiology Standardization Project lAmeri-
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8. Pearle JL. Correlation of helium and plethysmographic lung
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9. Miller WF, Scacci R. Cast LR. Laboralorv evaluation of
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10. Reinoso MA, Jett JR, Beck KC. Body plethysmography in
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I 1. Watanabe S. Renzetti AD Jr. Begin R. Bigler AH. Airway
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12. Fish JE. Rosenthal RR, Baira G. Menkes H. Summer W.
Permutt S. Norman P. Airway responses to methachiiline
in allergic and nonallergic subjects. Am Re\ Respir Dis
1976:1 1 3(5):579-586.

13. Crapo RO. Casaburi R. Coates AL. Enright PL. Hankinson

JL, Irvin CG, et al. Guidelines for methacholine and exer-
cise challenge testing, 1999. This official statement of the
American Thoracic Society was adopted by the ATS
Board of Directors, July 1999. Am J Respir Crit Care Med
2000:161(11:309-329.

14. Rodenslein DO. Stanescu DC. Francis C. Demonstration of

failure of body plethysmography in airway obstruction. J
Appl Physiol 1982:52(4):949-954.

15. Shore SA, Huk O, Mannix S. Martin JG. Effect ol panting

frequency on the plethysmographic determination of tho-
racic gas volume in chronic obstructive pulmonary dis-
ease. Am Rev Respir Dis 1 983: 1 28(0:54-59.

16. Shore S. Milic-Emili J. Martin JG. Reassessment of body
plethysmographic technique for the measurement of tho-
racic gas volume in asthmatics. Am Rex Respir Dis
l982:r26(3):5l5-520.

17. Bohadana AB, Peslin R. Hannhart B. Teeulescu D Inllu-
ence of panting frequencv on pleth\smographic measure-
ments of thoracic gas volume. J .^ppl Physiol
1982:52(31:7.^9-747.

18. Habib MP, Fngel LA. Inlluence of the panting technique on

the plethysmographic measurement of thoracic gas vol-
ume. Am Rev Respir Dis I97S:1 17(21:265-271.

19. Barter CE. Campbell -AH. Comparison of airways resis-
tance measurements during panting and quiet breathing.
Respiration I973:.30( I ):l-l I.

20. Chowienczyk PJ, Rees PJ, Clark TJH. Automated system

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AARCGl IDI I l\l ; lioD^ I'l l i in smock \l'll^ : :()()l Kl \ isios .V: ll'DATE

tor ihc mcasuicmciit dI airways rcNislaiKc. lung \oliimcs,
and now-volunic loops. Thorax I9«l:36( l2):944-949.

21. Bales JHT. Corroclinj; for the ihcrmoilynamic charactcris-
IJLs of a body plclhysmoiiraph. \n\\ Hiomcil ling
IW9:l7(6):(i47-h5.'i.

22. Lord PW, Brooks AGF. A comparison of nianiial and aulo-

nialcd niclhods ol' measuring airway rcsislance and tho-
racic gas \olunic. Thorax I977;.^2( 1 );6()-6(i.

23. Sander LR. C'ompiiler analysis versus technician analysis
ot" body plethysmographic analog recordings of airway re-
sistance and thoracic gas vohiiiie, Respir Care
1982:27(l):62-(i').

24. Brown R. Hoppni 1(1 Jr. Ingram Rll Jr. Sainidcrs N,\. Mc-

l-addcn l{R Jr. InlUiciicc ol abdonnnal gas on the Boyle's
law determination of thoracic gas volume. J .'\ppl Physiol
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25. Bargeton D, Banes G. Time characteristics and frec|uency re-

sponse of body plethysmograph. In; DuBois .'\B. Van dc
Woestijne KP. ller/og H, editors. Progress in respiration re-
search, body plethysmography. New York: S Karger; 1969.

26. Crapo RO. Morris AH. Clayton PD. Ni,\on CR. Lung vol-

umes in healthy nonsmoking adults. Bull Lur Physiopathol
Respir 1 982; 18( 3 );4 19-425.

27. NCCLS. GP26-A A quality system model for health care:
approved guideline (1999). Available from NCCLS:
phone 610-688-0100; Fax 610-688-0700; e-mail exof-
fice@nccls.org.

28. NCCLS. HS4-A A quality system model for respiratory
care: approved guideline (2000). Available from NCCLS:
phone 610-688-0100: Fax 610-688-0700; c-mail exof-
tlceC"' nccls.org.

29. Gardner RM. Clausen JL, Crapo RO. Lpler GR. Hankinson

JL, Johnson JL. Plummer AL. Quality assurance in pul-
monary function laboratories. .Xm Rev Respir Dis
1986:l34(3):625-627.

30. Quanjer PH. Tammeling GJ. Cotes JF. Pcdersen OF. Peslin

R. Yernault JC. Lung volumes and Ibrced ventilatory
flows. Report Working Party Standardization of Limg
Function Tests. Furopean Community for Steel and Coal.
Official Statement of the Furopean Respiratory Society.
Fur Respir J SuppI 1993 Mar: 16:5-40.

31. American Thoracic Society. Standardization of spirome-
try, 1994 update. Am J Respir Crit Care Med
1995:152(3):l 107-1 1.36.

32. American Thoracic Society . Puhiionarv function laboratory

management and procedure manual. Wanger J. editor.
New York: ATS: 1998..

33. Kanner RE. Morris AH, Crapo RO, Gardner RM. editors.
Clinical pulmonary function testing: a manual of uniform
laboratory procedures for the intermountain area. 2nd ed.
Salt Lake City: Intermountain Thoracic Society: 1984.

34. Ruppel GL. Manual of pulmonary function testing. 7th ed.

St Louis: Mosby- Yearbook: 1998.
.35. Demi/io DL. Allen PD. Beaudry PH. Coatcs AL. An alter-
nate method for the determination of functional residual
capacity in a plethysmograph .\m Re\ Respir Dis
1988:137(2):273-276.

36. Gibson GJ. .Measurement ol the mechanical properties of
the thorax, lungs, and airways. In: Las/.lo G, Sudluw MP,
editors. Measurement in clinical respiratory physiology.
New York: Academic Press; 1982.

37. Recommendations of British Thoracic Society and the As-

sociation of Respiratory Technicians and Physiologists.
Guidelines lor the mcasurenient of respiratory function.
Respir Med 1 994;88( 3 ); 1 65- 1 94.

38. Zarins LP. Clausen JL. Plethysmography In: Clausen JL.
editor. Pulmonary function testing: guidelines and contro-
versies. New York: Academic Press; 1982.

39. Pel/.cr A. Thomson ML. Effect of age. sex, stature, and
smoking habits on human airway conductance. J AppI
Physiol 1966:2 1 (2(;469-476.

40. NCCLS. C28-A2. How to define and determine reference
intervals in the clinical laboratory: approved guideline,
2nd ed. 2000. Available from NCCLS; phone 610-688-
0100; Fax 610-688-0700; e-mail exofficeC" nccls.org.

41. Gardner R.VI. Clausen JL. lipler G. Hankinson JL. Permutt

S. Plummer -XL. Pulmonary function laboratory personnel
qualifications. American Thoracic Society Position Paper.
ATS News. November 1982.

42. Garner JS. Hospital Infection Control Practices .Advisory,
Centers for Disease Control and Prevention. Guideline for
isolation precautions in hospitals. Am J Infect Control
I996;24{ 1 ) or http//w w w apic.org/htinl/resc/gdisolat.html.

43. Centers tor Disease Contriil and Prevention. Hospital Infec-

tion Control Practices Advisory Committee. Guideline for
infection control in health care personnel. 1998. Am J In-
fect Control 1998:26:269-354 or Infect Control Hosp Epi-
dennol 1998:19(61:407-463.

44. Larson FL. .APIC guideline for handwashing and hand anti-

sepsis in health care settings. Am J Inlect Control
1995:23(4);251-269.

45. Centers for DLsease Control ^: Prevention. (Juidelines for

preventing the transmission of tuberculosis in health-care
facilities. 1994. MMWR 1994;43(RR-l3):l-32 o;- Federal
Register l994;59(208):54242-54303 or http://aepo-xdv-
www.epo.cdc.gov/vvonder/prev2uid/m0035909/m(K13590
9.htm.

46. Rutala W.A. APIC guideline for selection and use of disin-

fectants. Am J Infect Control 1990:18(21:99-1 17.

47. Kirk 'il.. Kenday K. Ashvvorlh llA. Hunter PR. Laboratory

evaluation of a filter for the control cit cross-infection dur-
ing pulmonary function testing. J Hosp Infect
1992;20:193-198.

ADDII lONAI. Kl ADING

Coates AL. Peslin R. Rodenstein D. Stocks J. ERS/ATS Work-
shop Report Series. Measurement of lung volumes by plethy s-
mographv. Fur Respir J 1997:10:1415-1427.

Iiilcicstcd persons may iiliotocopy these Guidelines for iioncomnicivial purposes of scientific
or educational advaneemenl. Please credit AARC and KiSPIRATORY CarF JouinaL

RbSPIKAlURY CAR1-. • MAY 20Ui VuL 4ti NO 5

513

AARC (iriDiiUNi-:: Exercise Testing ior Evaluaiion of Hyk)XEmia and/or desatliration: 2(X)l Rivision & Update

AARC Clinical Practice Guideline

Exercise Testing for Evaluation of Hypoxemia and/or Desaturation:

2001 Revision & Update

ETD 1.0 PROCEDURE:

Exercise testing for evaluation of hypoxemia
and/or desaturation.

ETD 2.0 DESCRIPTION/DEFINITION:

Exercise testing may be performed to determine the
degree of oxygen desaturation and/or hypoxemia
that occurs on exertion. Desaturation is defined as a
vaUd decrease in arterial oxygenation as measured
by CO-oximetry saturation. (S.,o:) of y^c (based on
the reproducibility of HbO^ measurement at ±1%),'
an SaO: < 88%,-' and/or a blood gas PaO: ^ 55 torr.-*

2.1 Exercise testing may also be performed to
optimize titration of supplemental oxygen for
the correction of hypoxemia. An SpOi of 93%
should be used as a target.'

2.2 It is preferable that this procedure be per-
formed using a method that allows quantitation
of workload and heart rate achieved (as % pre-
dicted).

2.2.1 This evaluation can be incorporated
into other more complex test protocols
(eg, cardiac stress testing).

2.2.2 Continuous noninvasive measure-
ment of arterial oxyhemoglobin saturation
by pulse oximetry can provide qualitative
information and an approximation of oxy-
hemoglobin saturation, with a 4% de-
crease in Sp(), considered significant,"" but
evaluation of desaturation on exertion re-
quires analysis of arterial blood samples
drawn with the subject at rest and at peak
exercise.' ■''-

2.3 Arterial blood specimens may be obtained
by single puncture or by arterial cannulation."'''

2.4 Exercise testing performed with exhaled gas
analysis is addressed in a separate gLiideline.

2.5 This guideline is appropriate lor pediatric.
adult, and geriatric patients v\ ho are capable of
following test instructions and techniques.

2.5.1 The learning ability and communi-

cation skills of the patient being served,
should be taken into consideration when
performing these tests.
2.5.2 The neonatal population is not
served by this guideline.

ETD 3.0 SETTINGS:

Exercise testing may be performed by trained
personnel in a variety of settings including

3.1 pulmonary function laboratories

3.2 cardiopulmonary exercise laboratories

3.3 clinics

3.4 pulmonary rehabilitation facilities

3.5 physicians" offices

ETD 4.0 INDICATIONS:

Indications for exercise testing include

4.1 the need to assess and quantify the adequa-
cy of arterial oxyhemoglobin saturation during
exercise in patients who are clinically suspect-
ed of desaturation (eg, those who manifest dys-
pnea on exertion, decreased Di co- decreased
Pao-i at rest, or documented pulmonary dis-
ease);2.7.'5-'s

4.2 the need to quantitate the response to thera-
peutic inter\ention (eg. oxygen prescription,
medications, smoking cessation, or to reassess
the need for continued supplemental oxy-

gen

.:, 7.15.1')-: I

4.3 the need to titrate the optimal amount of
supplemental oxygen to treat hypoxemia or de-
saturation during acti\ity:--^--'--

4.4 the need for preoperative assessment for
lung resection or transplant;-^

4.5 the need to assess the degree of impaimient
for disability evaluation (eg. pneumoconiosis,
asbestosis).-^

ETD 5.0 CONTRAINDICATIONS:

5.1 Absolute contraindications include

5.1.1 acute electrocardiographic changes

514

Ri;Spiratc)r^ Care • \\\\ 200 1 Vol 46 No 5

AAKt (ll IDl-LINK: E\l kl LSI I'l.SriNG FOR EVALUATION ( )l ll'i lt)XEMIA AND/OR DliSATURATION: 2001 RliVISION & UPDATE

Miggestini; myocardial ischemia or seri-
ous cardiac dysrhythmias including
bradydysrhylhmias. tachydysrhythmias,
sici\ sinus syndrome, and nuihit'ocal pre-
mature ventricular contractions (F'VCs).
causuii: ssmptoms or hemod\namic com-
promise (occasional PVCs are not a con-
irainilication):-"' -"

5.1.2 unstahie angina;-''-''-'

5.1.3 recent myocardial inlarction (within
the previous 4 weeks) or myocarditis;-^'-*"

5.1.4 aneurysm of the heart or aorta;-''-''

5.1.5 uncontrolled systemic hyperten-

by exercise;-^ -"'

5.2.8 uncontrolled metabolic disease (eg,

diabetes, thyrotoxicosis, or myxede-

sion:

:>.26

5.1.6 acute thrombophlebitis or deep ve-
nous thrombosis;-'' -"

5.1.7 second- or third-degree heart
block ;-5-''

5.1.8 recent systemic or pulmonary embo-
lus;-'-"

5.1.9 acute pericaiditis;-^-^

5.1.10 symptomatic severe aortic steno-
sis;

5.1.11 uncontrolled heart failure;-^

5.1.12 uncontrolled or untreated asthma;

5.1.13 pLilmonary edema;-''

5.1.14 respiratory failure;-^

5.1.15 acute non-cardiopulmonary disor-
ders affected by exercise.

5.2 Relative contraindications include

5.2.1 situations in which pulse oximetry
may pro\ ide invalid data (eg. elevated
HbCO. HbMet. or decreased perfusion).
(See AARC Pulse Oximetry Guidelines.'")

5.2.2 situations in which arterial puncture
and/or arterial cannulation may be con-
traindicated;"'-

5.2.3 a non-compliant patient or one u ho
is not capable of performing the test be-
cause of weakness, pain, fever, dyspnea,
incoordination, or psychosis;-^-''

5.2.4 severe pulmonary hypertension (cor
pulmonale);-''-''

5.2.5 kmn\n electrolyte disturbances (hy-
pokalemia, hypomagnesemia);-''-"

5.2.6 resting diastolic blood pressure >
1 10 torr or resting systolic blood pressure
> 200 torr;-' -"

5.2.7 neuromuscular, nuisculoskelclal. or
rheumatoid disorders that are exacerbated

ma;

!s.:'>

5.2.9 S,,(). or .S|,(), < S5'/( on room air;-''
5.2.1U complicated or advanced pregnan-

5.2.11 hvpertrophic cardiomyopathy or
other lorms t)f outflow tract obstruction;-''

5.2.12 patient's inability to cooperate or
follow directions for testing.

ETl) 6.0 PRKC Al TIONS AM)/()R PO.S.SIBLE
COMPLICATIONS:

6.1 Indications for immediate termination of
testing include

6.1.1 electrocardiographic abnormalities
(eg, dangerous dysrhythmias, ventricular
tachycardia. ST-T wave changes);-"' -''

6.1.2 severe desaturation as indicated by
an SaO; ^80% or SpO: <83% (A number of
pulse oximeters have been found to over-
estimate Spo:'-'-'' '") and/or a \{)Vc fall
from baseline values; (Underestimation of
saturation has been noted to occur u ith
certain pulse oximeter models. ''■'"')

6.1.3 angina;-^-''

6.1.4 hypotensive responses;

6.1.4.1 a fall of > 20 torr in systolic
pressure, occurring after the normal ex-
ercise rise;'^

6.1.4.2 a fall in s_\stolic blood pressure
beKn\ the pre-exercise level;'"

6.1.5 lightheadedness;-''-''

6.1.6 request from patient to terminate
test.

6.2 Abnormal responses that may require dis-
ct)nliiuiation i)f exercise include

6.2.1 a rise in systolic blood pressure to >
250 torr or of diastolic pressure to > 120
loir.-' -'' or a rise in systolic pressure of <
20 ton from resting le\el;

6.2.2 mental confusion or headache;-"'-*'

6.2.3 cyanosis;-^-"

6.2.4 nausea or vomiting;

6.2.5 muscle cramping.--''-''

6.3 Hazards associated with arterial puncture,
arterial cannulation. and pulse oximetry:'" '-
Pulse oximetry is a noninvasive safe procedure,
but because of device limitations, false-nega-

RESPIRATORV CaRK • Ma"! 2001 Voi. 46 No 3

51.S

A ARC Gl'IDHLINH: EXERCISE TESTING FOR EVALUATION Ol HM'OXHMIA AND/OR DESATURATION: 2fX)l REVISION & UPDATE

live results for hypoxemia" and/or false-posi-
tive results for normoxcniia or hyperoxemia
may lead to inappropriate treatment of the pa-
tient. Although it is rare, tissue injury may
occur at the measuring site as a result of probe
misuse, such as pressure sores from prolonged
application or electrical shock and burns from
the substitution of incompatible probes be-

tween instruments

30,38-42

ETD 7.0 LIMITATIONS OF PROCEDURE/
VALIDATION OF RESULTS:

7.1 Limitations of equipment:

7.1.1 Because of possible limitations of
pulse oximetry with exercise and at rest,
measurements may read falsely low or
falsely high and should be validated by
comparison with baseline arterial samples
analyzed by CO-oximetry."'-'''*'

7.1.1.1 Only a limited number of pulse
oximeters have been validated with re-
sults of concurrent arterial blood gas
analysis in diseased subjects under ex-
ercise conditions.'^

7.1.1.2 Overestimation of oxygen satu-
ration may occur with carboxyhe-
moglobin saturations (> 4 %).-■■*•*•■*'
7.1.L3 Decreasing accuracy in SpOa
has been reported with desaturations to
< SWc. This is assumed to be the result
of limitations of in vivo calibration to
85% with extrapolation of the calibra-
tion curve below that value. '''•■*^
7.L1.4 Decreased perfusion with car-
diovascular disease, vasoconstriction,
or hypothermia may result in false-
positive results or no valid data in
some pulse oximeter models." ■'^
Use of an alternative site should be
evaluated (eg, ear, finger, forehead).
Alternative handwarming methods
may be used to increase circulation.

7.1.1.5 Reduced ear perfusion associat-
ed with heavy exercise has been shown
to affect SpO: in some models of pulse
oximeters."-*''-''*

7.1.1.6 Motion artifact may appear
with exercise. '^■^" Some pulse oxime-
ters are better then others at rejecting
motion artifact." ■'*-

7.1.1.7 Pulse oximeter response time

may be inadequate to describe rapid
changes in saturation.^- "'■'''^

7.1.1.8 Skin pigmentation should, in
theory, not affect pulse oximeter read-
ings, but various studies report con-
nicting data depending on the manu-
facturer and model. ^■"*-''

7.1.1.9 Hemoglobin disorders may af-
fect the accuracy oi the pulse oximeter
reading. '^-'^•''^ Important underestima-
tion of arterial saturation may result
from pulse oximetry in subjects with
total hemoglobin levels of <8 g/dL."^'

7.1.1.10 Pulse oximetry is less useful
over the range in which large changes
in PaO: are associated with small
changes in SaO: ('S' PaO: ^60 torr).'*
7.LL11 Ambient light during testing
may interfere with measurements of
pulse oximetry.''"'

7.1.1.12 Exercise testing in which oxy-
hemoglobin saturation by pulse oxime-
try is the only variable measured pro-
vides limited information.
7.1.2 Limitations related to the patient:

7.1.2.1 Additional limitations common
to arterial sampling and analysis under
resting conditions should be consid-
ered. ^'-^^

7.1.2.2 Patient cooperation level or
physical condition may limit the sub-
ject's ability to exercise at a workload
sufficient to evoke a response.-" -'' Vari-
ables that are not adequately monitored
(eg, free walking) have limited applica-
tion.

7.2 Validation of results:

7.2.1 Arterial blood gas samples should
be obtained at rest and at peak exercise.
Samples from single arterial punctures
have been shown to be equi\ alent to sam-
ples drawn from indwelling cannulas.''-^"'

7.2.2 In the unlikely event that a single
puncture at peak exercise is unsuccessful
in an uncannulated patient, a sample
drawn within 10-15 seconds of the termi-
nation of exercise will suffice unless anal-
ysis shows a decrease from the resting
values, in which case quantitation of de-

516

Respiratory Care • May 2001 Vol 46 No 5

AARC Guideline: Exercise Testing for Evaluation of Hypoxemia and/or desaturation: 2001 Revision & Update

satiiratiiMi ret|iiires a peak exercise sample
obtained hy cannula.''"

7.2.3 Arterial blood gas results should be
obtained according to the Guidelines for
arterial blood gas sampling and for arteri-
al blood gas analysis." '-^'

7.2.4 Validity of piilsL- o\mietr\ results is
\erified by comparison with the results of
analysis by CO-oximetry.'"^' preferably
at rest and at end of exercise.

7.2.4.1 Spo may be used to assess re-
sponse to supplemental oxygen. If ad-
ministration of supplemental oxygen
does not improve a low Sp02. arterial
blood analysis may be warranted.

7.2.4.2 Testing should be performed in
compliance with the AARC Pulse
Oximetry Clinical Practice Guideline.-^"

7.2.4.3 Correlation between pulse
oximetry heart rate and palpated pulse
rate and/or electrocardiogram should
be established.'*'^

7.2.4.4 Pulse oximetry with pulse
waveform display may be desirable.
For patients with normal adult
hemoglobin, the highest accuracy and
best performance is attained when the
probe is attached to the patient in such
a way that the arterial signal has the
largest possible amplitude, which is
only available w iih systems that yield a
plethysmographic tracing.''^

KTD S.(» ASSKSSMKNT OF M FI):

Exercise testing for evaluation ot hypoxemia and/or
desaturation may be indicated (see section ETD 4.0
INDICATIONS) in the presence of

8.1 a history and physical indicators suggesting
hypoxemia and/or desaturation (eg, dyspnea,
pulmonary disease);

8.2 abnormal diagnostic test results (eg. Di.co-
FEV|. resting arterial blood gases including di-
rectly measured HbO:, HbCO. and Hb.Mct):

8.3 the need to titrate or adjust a therapy (eg,
supplemental oxygen ).

ETD 9.0 ASSESSMENT OF QUALITY OF
TEST AND \ALll)n V OF RESULTS:

The consensus of the committee is that all diag-
nostic procedures should follow the quality model
described in the NCCLS GP26-A A Quality Sys-
tem Model for Health Care.^*^ (Fig. I ) The docu-
ment describes a laboratory path of workflow
model that incorporates all the steps of the proce-
dure. This process begins with patient assessment
and the generation of a clinical indication for test-
ing through the application of the test results to
patient care. The quality system essentials de-
fined for all health care services provide the
framew ork for managing the path of w orktlow. A
continuation of this model for respiratory care
services is further described in NCCLS HS4-A A
Quality System Model for Respiratory Care.^'' In
both quality models the patient is the central
focus.

Quality
System
Essentials

Organization
Personnel
Equipment
Purctusing/

Invenlofy
Process

control
Documents/

Records
Occurence

management
Internal

assessnKnt
Process

improvement
Service and

Salisfaclion

Pulmonar) Diagnostics Patii of Workflow

Pretest Testing Session

Panenl Training

Tcsl l^rformancc

Results Review and Selection

Patient Assessment for Further Testing

Patient Assessmeni
TesI Request
Patient Preparation
Equipment Preparation

Infortnalion Management

Inlomiation System

Quality system essentials
apply to all operations
in the path of workflow

Results Report
Interpretation
riinical Consult

Fig. 1. Structure for a Quality System Model for a Pulmonary Diagnostics Service (From Reference 55. with permission)

Respiratory Care • May 2001 Vol 46 No 5

517

AARC ("inni:i.iNi;: ExHRCiSE Testing K)R Evall ahon oi Hn poxkmia and/or DbSATURAiioN: 2(X)I Riaision & Uf'date

9.1 General considerations include:

9.1.1 As part of any quality assurance pro-
gram, indicators must be developed to
monitor areas addressed in liie path of
u'orkt'lovv.

9.1.2 Each laboratory should standardize
procedures and demonstrate intertechnol-
ogist reliability. Test results can be con-
sidered valid onlv' it" they are deri\ed ac-
cording to and conform to established lab-
oratory quality control, quality assurance,
and monitoring protocols.

9.1.3 Documentation of results, therapeu-
tic intervention (or lack of) and/or clinical
decisions based on the exercise testing
should be placed in the patient's medical
record.

Report of test results should contain a
statement by the technician performing
the test regarding test quality (includ-
ing patient understanding of directions
and effort expended) and. if appropri-
ate, which recommendations were not
met.

9.1.4 The type of medications, dose, and
time taken prior to testing and the results
of the pretest assessment should be docu-
mented.

9.1.5 Test results should be interpreted by
a physician, taking into consideration the
clinical question to be answered.''^

9.1.6 A technologist who has not met an-
nual competency requirements or whose
competency is deemed unacceptable as
documented in an occurrence report
should not be allowed to participate, until
he has received remedial instruction and
has been re-evaluated.

9.1.7 There must be evidence of active re-
view of quality control, proficiency test-
ing, and physician alert, or 'panic' values,
on a level commensurate with the number
of tests performed

9.2 Calibration and quality control measures
specific to equipment used in exercise testing
for desaturation include:

9.2.1 Calibration procedures as defined
by the laboratory protocols and manufac-
turer's specifications should be adhered

9.2.2 Treadmills and bicycle ergometers
should be calibrated according to the
manufacturer's recommendations, with
periodic re-verification. (One reference
suggests every 3-6 months.'*-)

9.2.3 Pulse oximeters monitors should be
maintained as described under quality as-
.surance in the manufacturer's manual.

9.2.4 Biological controls should be tested
regularly (self-testing of normal laborato-
ry staff). ^«

9.3 Test quality: Results of arterial blood gas
analysis and/or Spo, should confirm or rule out
oxygen desaturation during exercise to validate
the patient's clinical condition.

9.4 Test results:The exercise should have a
symptom-limited or physiologic end point docu-
mented (eg. heart rate or onset of dyspnea).

ETD 10.0 RESOURCES:
10.1 Equipment:

10.1.1 Treadmill, cycle ergometer, or
equivalent equipment, adaptable to pa-
tients who may be severely limited (eg,
low-speed treadmill, low-watt ergometer,
arm crank ergometer). -^••^^•^'~^' Other
forms of exercise may be utilized (stair
climbing, step test, timed walking): how-
ever, such modes do not eliminate the ne-
cessity for adequate monitoring as de-
scribed in Sections 7 and 9 and the neces-
sity for adequate documentation of
procedure and patient response.

10.1.2 Arterial blood sampling equipment
tor single puncture or arterial cannulation
and analyzers that have been properly cal-
ibrated and for which multilevel controls
indicate proper function" '-^■'

10.1.3 Pulse oximeter monitor and related
accessories.^"

10.1.4 Electrocardiographic monitor with
the capacity to nti)nitor heart rate to a pre-
dicted maximum and accurately display
cardiac rhythm during exercise. (Multiple
leads are preferred.)-''-''

10.1.5 Resuscitation equipment including
oxygen with \arious delivery devices,
such as nasal cannula and mask.-^ -"

10.1.6 An easils accessible cardiac arrest
cart and delibnllaior with resuscitation

518

Ri:SiMKAT()R'i Cari; • Ma^ 2001 Vol 46 No 5

AARC tiL 1I)1.1.IM.: LM.KCISI. iLSriNC K ll< lA Al 1 A I ION ( il ll'i !■< IXIMIA AND/OR DESAIURATION: 20()1 RhVISION & UPDATE

l(KI.7 lilcmd pressure nionilorint; do\ice.

maiuuil or automatic. (If an aiilomaled

system is used, a manual hlood |iressiire

cutT aiul slcthoscoix' slioidil he asailahle

as a backup.)'^ '"

10.1.8 Visual aids (eg. Borg scales for

dyspnea and iatiszue) thai are large, easy

to read, and in clear view.^""- "'

10. 1.*) RK)od gas sampling and anal) sis

equipment. -"-^-■■''■*

10.2 Background history and data:

10.2.1 Results ot appropriate haseline di-
agnostic tests and patient history (eg,
electrocardiogram, chest radiograph, and
pulmonary function test results) should be
aNadahlc.'-'-"-'^

10.2.2 The need l\)r written consent
should be determined w ithin the specific
institution.-"-"

10.2.3 A list of the patient's current medi-
cations and an\ pharmacologic allergies
should be included.

10.3 Personnel:

10.3.1 The presence of a physician trained
in exercise testing may be required de-
pending on patient condition and hospital
policy.-'-"'^^

10.3.2 Personnel administering the test
should possess experience and knowl-
edge in exercise physiology and testing,
including arterial blood gas sampling
and analysis; cardiopulmonary resusci-
tation (certified in Basic Cardiac Life
Support, or BCLS. Qualification in Ad-
vanced Cardiac Life Support, or ACLS,
is recommended); ECG abnormality
recognition: oxygen therapy: blood pres-
sure monitoring: and application and
limitations of pulse oximeters.-** Train-
ing and demonstrated competency must
be documented for all testing person-
nel.^"

10.3.3 Testing personnel should have the
knowledge and skills to respond to ad-
verse situations with the patient and to
know when cessation of further testing is
indicated (versus coaching the patient to
continue ).-**• -"'-^^

KTD 11.0 MOM r()Kl\(;:

11.1 Keconunemled momlormi; ol patient dur-
ing testing:

11.1.1 Electrocardiograph with strip
recorder, preferably screened m real-time
to check lt)r displaced leads,

11.1.2 Oxygen delivery devices with doc-
umented F|)(),

11.1.3 Physical assessment (chest pain,
leg cramps, color, perceived exertion,
dyspnea)-'--^

11.1.4 Respiratory rate---''

11.1.5 Patient cooperation and eflorl level

11.1.6 Borg, modified Borg, or visual ana-
log dyspnea or symptom scales'^- ''-^

11.1.7 Blood gas sampling using site and
technique consistent with the AARC
Clinical Practice Guideline for blood gas
sampling," and NCCLS Guidelines'^

11.1.8 Continuous monitoring of oxy-
genation status (SpO;)

11.1.9 Heart rate, rhythm, and ST-T wave
changes-- -"

11.1.10 Blood pressure"'"

11.2 Recommended equipment monitoring dur-
ing testing: Pulse waveforms of Spo, and/or
SaO: should be analyzed to assure adequate sig-
nal acquisition for reliable readings.

ETD 12.0 FREQUENCY:

The frequency of testing depends on the patient's
clinical condition and the need for changes in ther-
apy. Exercise may be repeated for certification of
supplemental o.xygen needs.

ETD 13.0 INFECTION CONTROL:

13.1 The staff, super\isors. and physician-di-
rectors associated with the pulmonary laborato-
ry should be conversant with "Guideline for
Isolation Precautions in Hospitals" made b\' the
Centers for Disease Control and the Hospital
Infection Control Practices Ad\ isoiA Commit-
tee (HICPAC),'''' and develop and imiilcment
policies and procedures for the laborator\ that
comply with its recommendations for Standard
Precautions and Transmission-Based Precau-
tions.

13.2. The laboratory's manager and its medical
director should maintain communication and

Ri:si'lRATC)R^- Cari- • Ma'i 2001 Vol 4fi No 3

51')

AARC Cli'iDKLiNi;: E\i:Kcish Ti-stint; ior Faai.i ai ion oi Hmhiximia and/or I)i;saturati()n; 2(K)I Revision & Update

cooperation with llic iiislilulion's infection con-
trol service and the personnel health ser\ ice to
help assure ct)nsistency and thoroughness in
complying with the institution's policies related
to immunizations, post-exposure prophylaxis,
and job- and conimunil\ -related illnesses and
exposures."'
13.3 Primary considerations include:

13.3.1 adet|uale handwashing,''**

13.3.2 pro\ ision ol prescribed \ entilation
with adequate air exchanges/'''

13.3.3 careful handling and thorough
cleaning and processing of equipment.''''
Procedure-specific considerations include:

13.3.3.1 disposable items are for single
patient use;

13.3.3.2 disposable electrt)des should
be used for electrocardiographic moni-
toring with Standard Precautions ob-
served during patient skin preparation.
Cables and equipment that touch the
patient should be wiped down with a
disinfectant after each u.se;

13.3.3.3 reusable pulse oximeter
probes should be cleaned between pa-
tient use. following the manufacturer's
guidelines.

13.3.4 the exercise of particular care in
scheduling and interfacing with the pa-
tient in whom a diagnosis has not been es-
tablished.

ETD 14.0 .\GE SPECIFIC ISSUES

14.1 This guideline does not apply to the
neonatal population.

14.2 This CPG document applies to pediatric,
adolescent, adult, and geriatric populations.

14.3 Test instructions and techniques should be
given in a manner that takes into consideration
the learning ability, communication skills, and
age of the patient being served.

Cardiopulmonary Diagnostics Giiideiines Com-
mittee (the principal author is listed first):
Catherine M Foss US RRT RFIT. Ann Arbor MI

Susan Bhmslww BS RRT RFIT. Mason Ml
CarlMottram BA RRT RPFT. Chair. Rochester MN
Grci^i^ Riippel MEd RRT RFIT. St Louis MO
Jack Wander MS RRT RPFT. I.euexa KS

The current Pulmonary Diagnostic Clinical Practice
Guidelines Committee updated an earlier version
(Exercise testing for evaluation of hypoxemia
and/or desaturation. Respir Care 1992;37(8):907-
912) and gratefully acknowledges the contribution
of those individuals who provided input to that ear-
lier version: Ke\ in .Shiake. Robert Brown, and
Michael Kochansky.

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9. Douglas NJ. Brash HM. Wraith PK. Calverley PM.
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10. Hansen JE, Casaburi R. Validity of ear oxmietrv in clinical
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11. Powers SK. Dodd S, Woodyard J. Beadle RE.
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12. Smyth RJ, D'Urzo AD. Slutsky AS. Galko BM, Rebuck
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13. Ries .AL. Fedullo PF, Clausen JL. Rapid changes In arterial
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19.

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18. Ries AL. Farrow JT. Clausen LF. Pulmonary function tests
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Moore DP. Weston AR. Hughes JMB. Oakley CM. Cle-
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Carlone -S, Angeliei E. Palange P. Sena P. Farber MO. Ef-
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28. Pina IL. Balady GJ. Hanson P. Labovitz AJ. Madoiuia

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29. Wasserman K. Hansen JE. Sue DY. Casahuri R. Whipp BJ.

Principles of exercise testing and interpretation. 3rd ed.
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American Association for Respiratory Care. AARC Clini-
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Norton LH. Squires B. Craig P. McLeay G. McGrath P.
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Severinghaus JW. Naifeh KH. Koh SO. Errors in 14 pulse
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Dubach P. Froelicher VF. Klein J. Oakes D. Grover-
McKay M. Friis R. Exercise-induced hvpolension in a
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Hannhart B. Michalski H. Delorme N. Chapparo G. Polu J-
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PA. ECRl.June29. 1990.

Wangcr J. editor. ATS pulmonary function laboratory
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Morris RW. Niiirn M. Tonla T.A. .A comparison of tll'leen
pulse oximclers. Part I; a clinical comparison; Part II: a test
of performance under conditions of poor perfusion.
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Williams J. Powers S. Stuart M. Hemoglobin desaturaiion
in highly trained endurance athletes during heavy exercise.
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Ear lobe blood samples for blood gas analysis al rest and
during exercise. Br J Dis Chest 1971:65:58-65.
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Criswcll D. Validity of pulse oximetrx during exercise in

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clilc ciulunmcc ;ilhlclcs. J AppI I'hvsiol 1 W2;72(2):455-

458.
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Ohmeda .^7(H) pulse o.xinieter. Thorax 1987:42:892-896.
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limes 1999;2.^(2):45-48.89.

52. Poets CF. Stebbens VA. Detection of movement artifact in
recorded pulse o.ximeter saturation. Fur .1 Pcdiair
I997:I56(I0):808-811.

53. Severinghaus JW. Koh SO. Effect of anemia on pulse
oximeter accuracy at low saturation. J Clin Monit
1990(6):85-88.

54. Blonshine S, Albert! R. Olesinski RL. NCCLS H1I-A3.
3rd ed. Procedures for the collection of arterial blood spec-
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from NCCLS; phone 610-688-0100; Fax 610-688-0700; e-
mail exoffice@nccls.org.

55. NCCLS. GP26-A A quality system model for health care:
approved guideline ( 1999|. Available from NCCLS: phone
610-688-0100: Fax 610-688-0700: e-mail exoffice®
nccls.org.

56. NCCLS. HS4-A A quality system model for respiratory
care. Available from NCCLS: phone 610-688-0100: Fax
610-688-0700; e-mail exofficeCg'nccls.org.

57. European Respiratory Society. Clinical exercise testing
with reference to lung diseases: indications, standardiza-
tion and interpretation strategies. ERS Task Force on Stan-
dardization of Clinical Exercise Testing. Eur Respir J
1997:10(1 1):2662-2689.

58. Morgan MDL. Exercise testing. In: Hughes JMB. Pride
NB editors. Lung function tests: physiological principles
and clinical applications. Philadelphia: WB Saunders; 1999.

59. Lear SA, Brozic A. Myers JN. Ignaszewski A. Exercise
stress testing: an overview of current guidelines Sports
Med 1999: May 27 (5):285-312.

60. Martin TW. Zeballos RJ. Weisman IM. Use of arm crank
exercise in the detection of abnormal pulmonary gas ex-
change in patients at low altitude. Chest 1992:102:169-
175.^

61 . Martin TW, Zeballos RJ, Weisman IM. Gas exchange dur-
ing maximal upper extremity exercise. Chest 1991 ;99:420-
425.

62. Borg GAV. Psycho-physical basis of perceived exertion.
Med Sci Sports Exercise 1982;14:377-381.

63. Borg GA. Borg's perceived exertion and pain scales.
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1999:13:171-181.

65. Aitken RCB. Measurement of feelings using \ isual ana-
logue scales. Proc R Soc Med 1969:62:989-993.

66. Gamer JS. Hospital Infection Control Practices Advisory
Committee, Centers for Disease Control and Prevention.
Guidelines for isolation precautions in hospitals. Atlanta
GA: Centers for Disease Control and Prevention, 1-01-
1 996. www.cdc.gov or Am J Infect Control 1 996:24( 1 ):24-52.

67. Centers for Disease Control and Prevention, Hospital In-
fection Control Practices Advisory Committee. Guideline
for infection control in health care personnel. 1998. Am J
Infect Control 1998;26:269-354 or Infect Control Hosp
Epidemiol 1998:19:407-463.

68. Larson EL. APIC guideline for handwashing and hand an-
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.\DDlTION.Al. Rt.^UI.NC;

Jones NL. Clinical exercise testing. 4th ed. Philadelphia: WB
Saunders Co; 1997.

Zavala D. Manual on exercise testing. 2nd ed. Iowa City: Uni-
versity of Iowa Press; 1987.

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Interested persons may photocopy these Guidelines for noncommercial purposes of scientific
or educational advanccnicnl. Please credit AARC and Rl SI'lR \TOR^■ Carf .lournal.

52:

Respiratory Care • May 2001 Vol 46 No 5

AARCGuidfxine:Mi-:tii\(ii()i INI C'liMi.BNGE Testing: 2001 Revision & Update

AARC Clinical Practice (Guideline

Methachollne Challenge Testing: 2001 Revision & Update

MCT 1.0 PROCEDURE:

Mclliacliolinc challcniic test. This guideline does
not address other hroiiehial challenges (eg, his-
tamine, exereise. occupational exposures, specific
antigens, i.socapnic hyperventilation.)

MCT 2.0 DES( RIPTION/DKI INITION:

2.1 The nieihacholine challenge test is one
nietln)d oT assessing airway responsi\eness. In
this lest, the patient inhales an aerosol ol'one or
more concentrations ot methacholme. Results
of pulmonary function tests (eg. spirometry,
specific conductance) performed before and
after the inhalations are used to quantitate re-
sponse. This guideline applies to adults and
children capable of adequately performing
spirometry or body plethysmography and of co-
operating during the course of the challenge.

2.2 A positive test is defined as a decrease from
the baseline forced expiratory volume in the
first second (FEV| ) or of the postdiluent FEV|
\ alue of 20'/ . or oi a decrease in specific ei>n-
ductance of 35-45% from the baseline or post-
diluent \akie.'"*

MCT 3.0 SETTINGS:

Possible settings include:

3.1 pulmonar\ function laboraloiy;

3.2 clinic or physician's office:

3.3 field site (eg. occupational setting or unrk-
place).

MCT 4.0 INDICATIONS:

Indications for testing include:

4.1 the need to exclude a diagnosis of airway
hyperreactivity (ie, asthma):' -^''

4.2 the need to evaluate occupational asthma;'-

4.3 the need to assess the severity of h\ perre-
sponsiveness:' -

4.4 the need to determine the relalne risk o\\\c-
\eloping asthma:-

4.5 the need to assess response to therapeutic

inter\entions:-

MCT 5.0 CONTRAINDK VITONS:

5.1 Absolute contraiiulications are:

5.1.1 ventilators impairment: FEV| <50%
of predicted or < 1 .0 L;- |This may be a
relative contraindication depending on the
age or size of the patient or on the pres-
ence of a restrictive lung disorder (re-
duced forced vital capacity, or FVC. with
a relatively normal FRV|/FVC)1:

5.1.2 heart attack or stroke w ithin the pre-
vious 3 months;' -

5.1.3 know n aortic or cerebral aneurysm;'-

5.1.4 uncontrolled hypertension [The
American Thoracic .Society (ATS) sug-
gests systolic pressure > 200 and/or dias-
tolic pressure >1 10 mm Hg.|.-

5.2 Relati\e contraindications are:

5.2.1 \entilatory impairment: FEV| >
50% or > 1 .5L but < 60' r of predicted;-

5.2.2 inability to perform spirometry of
acceptable quality ;-

5.2.3 significant response to the diluent, if
administered (ie. > lO'f fall in FEV| from
baseline):'"

5.2.4 upper- i)r lower-respiratory-tract in-
fection within previous 2 to 6 weeks;'"'-

5.2.5 cunent use of cholinesterase-inhibitor
medication ( for mya.sthenia gravis): -

5.2.6 pregnancy (The effect of metha-
choline on the fetus is unknow n. ):'-'

5.2.7 lactatiim:''

5.3 i-ailure to w ithhold mediealions ma_\ aflect
the meihacholine challenge test. Recommended
periods for withholding medications are gener-
ally based on their duration of action.' - Labora-
tories may choose to develop a simplified with-
holding schedule that makes allowances forain
of the following used b\ the palienl:

Respiratory Care • May 2001 Voi. 46 No 5

52:

A ARC Guideline: Methacholine Challenge Testing: 2001 Revision & Update

Agent

Withholding Time

short-acting inhaled
bronchodilators

6-8 hours

long-acting inhaled
bronchodilators (eg: sahiieterol.
formoterol)

4S iiours

anticholinergic aerosols
(eg: ipratropium)

24 hours

tiotropium

up to 1 week''*

disodium cromoglycate

8 hours

nedocromil

48 hours

oral beta2-adrenergic agonists

24 hours

theophyllines, depending on
specific preparation-

12-48 hours

leukotriene modifiers

24 hours-

corticosteroids, inhaled or oral
(may decrease
hyperresponsiveness)

Duration of effect
is unknown but

may be prolonged.'-"'

5.4 Foods: Ingestion of coffee, tea. cola drinks,
chocolate, or other foods containing caffeine
may decrease bronchial responsiveness. These
substances should be withheld on the day of test.

5.5 Other factors that may confound results in-
clude:

5.5.1 smoking.'''

5.5.2 occupational sensitizers,'**

5.5.3 respiratory infection, "•'-

5.5.4 specific antigens,'*'

5.5.5 vigorous exercise.-" -- (Performing
other bronchial challenge procedures or
exercise testing immediately prior to
methacholine challenge may affect inter-
pretation.)

MCT 6.0 HAZARDS/COMPLICATIONS:

Possible hazards or untoward reactions include:

6.1 bronchoconstriction, hyperintlalion, .severe
coughing:

6.2 hazards associated with spirometry, such as
dizziness, light-headedness, chest pain:-^

6.3 possible exposure of testing personnel to
provocative substance.

MCT 7.0 LIMITATIONS OF METHOD &
VALIDATION OF RESULTS:

7.1 Limitations of pulmonary function testing
used to quantitate response including intralabo-
ratory variability for each pulmonary function
test variable:

7.1.1 In some patients, spirometry may

not be sensitive enough or specific
enough to detect response, and other mea-
surements such as airways resistance
(Ra«) and/or specific conductance (sGaw)
may be used. Differences of opinion exist
regarding the spirometric values that best
track response in particular airways.'--''

7.1.2 Deep inspiration taken while perform-
ing spirometry variably alters bronchial
tone and may result in either bronchocon-
striction or bronchodilatation.-'^'-^

7.1.3 Poor patient effort during pul-
monary function testing can produce
false-positive results and make interpreta-
tion more difficult or impossible. Results
from spirometry should be acceptable ac-
cording to the most recent ATS recom-
mendations, and the quality of the flow-
volume curves should be examined after
each maneuver.--**

7.1.4 Spirometry .should be performed ac-
cording to the cun^ent acceptability guide-
lines of the ATS. Alternatively, the expira-
tory maneuver can be shortened to about 2
seconds after the methacholine doses are
inhaled if FEV| is the only outcome mea-
sure. If this shortened expiratory maneu-
ver is used, care should be taken to assure
that the inspiration is maximal.- After the
inhalation of diluent (if used) and of each
dose of methacholine, FEV] measure-
ments should be made at 30 and 90 sec-
onds after the last inhalation. The time in-
terval between doses should be standard-
ized at 5 minutes to keep cumulative
effect constant.

7.2 A limitation of the method is the variability
due to the effects of various factors including
medications, time of day. and differences in
technique and equipment.

7.3 Inconsistencies in technique and equipment
can affect the amount of agonist reaching the
airways and. thus, the subject's response —
making meaningful interpretation difficult or
impossible. Factors influencing response that
must be controlled and held constant across
testing include nebuli/er output and particle
size, volume inhaled, length (if breath-hold, and
inspiratory flow.---^--"'

7.4 If clinical suspicions are not confirmed by

52.

Respiratory Care • May 2001 Vol 46 No 5

AARC Guideline: Mini \( ii< )i im Cm \i i i noi Ti:sting: 2001 Revision & Update

one icsl, addiiioiuil ic^is iua_\ Ix' iiKlicalcd.
7.5 The tinal tost report should include:

7.5.1 PC':i)HHV| (ic. the provocative con-
centration that causes a 20'/; tall in FHV|).

7.5.2 coniinent on tiie atlec|uac\ ot spiro-
nielric elToii and i|ualil\ oT other mea-
surements;