critical care secrets

CRITICAL CARE


CRITICAL CARE

Fifth Edition
Polly E. Parsons, MD

E.L. Amidon Professor and Chair, Department of Medicine, University of Vermont
College of Medicine; Medicine Health Care Service Leader, Fletcher Allen Health Care,
Burlington, Vermont

Jeanine P. Wiener-Kronish, MD

Henry Isaiah Dorr Professor of Research and Teaching in Anesthetics and Anesthesia,
Harvard Medical School; Anesthetist-in-Chief, Massachusetts General Hospital,
Boston, Massachusetts


3251 Riverport Lane
St. Louis, Missouri 63043
Critical Care Secrets
Fifth Edition

ISBN: 978-0-323-08500-7

Copyright © 2013 by Mosby, an imprint of Elsevier Inc.
Copyright © 2007, 2003, 1998, 1992 by Mosby, Inc, an affiliate of Elsevier Inc.
All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any
means, electronic or mechanical, including photocopying, recording, or any information storage and
retrieval system, without permission in writing from the Publisher.

Notice
Knowledge and best practice in this field are constantly changing. As new research and experience
broaden our knowledge, changes in practice, treatment, and drug therapy may become necessary
or appropriate. Readers are advised to check the most current information provided (i) on
procedures featured or (ii) by the manufacturer of each product to be administered, to verify the
recommended dose or formula, the method and duration of administration, and contraindications.
It is the responsibility of the practitioner, relying on his or her own experience and knowledge
of the patient, to make diagnoses, to determine dosages and the best treatment for each individual
patient, and to take all appropriate safety precautions. To the fullest extent of the law, neither
the Publisher nor the editors assume any liability for any injury and/or damage to persons or
property arising out of or related to any use of the material contained in this book.
Library of Congress Cataloging-in-Publication Data
Critical care secrets / [edited by] Polly E. Parsons, Jeanine P. Wiener-Kronish. – 5th ed.
p. ; cm. – (Secrets series)
Includes bibliographical references and index.
ISBN 978-0-323-08500-7 (pbk. : alk. paper)
I. Parsons, Polly E., 1954- II. Wiener-Kronish, Jeanine P., 1951- III. Series: Secrets series.
[DNLM: 1. Critical Care–Examination Questions. WX 18.2]
616.02’8–dc23
2012017925

Executive Content Strategist: James Merritt
Content Development Specialist: Barbara Cicalese
Publishing Services Manager: Anne Altepeter
Project Manager: Louise King
Design Manager: Steven Stave

Printed in China
Last digit is the print number: 9

8 7 6 5

4 3 2 1


To our husbands, Jim and Daniel, and our children, Alec, Chandler, Jessica, and Samuel,
for their patience and support, and for allowing us to take the time to complete this edition


CONTRIBUTORS
Neil Agrawal, MD
Cardiology Specialist, Oklahoma Heart Institute, Tulsa, Oklahoma

Ali Al-Alwan, MD
Clinical Instructor, Pulmonary and Critical Care Medicine, University of Vermont College of
Medicine; Fellow, Pulmonary and Critical Care Medicine, Fletcher Allen Health Care, Burlington,
Vermont

Hasan B. Alam, MD, FACS
Professor of Surgery, Harvard Medical School; Director of Surgical Critical Care/Acute Care
Surgery Fellowship Program, Division of Trauma, Emergency Surgery, and Surgical Critical Care,
Massachusetts General Hospital, Boston, Massachusetts

Rae M. Allain, MD
Assistant Professor of Anesthesia, Harvard Medical School; Division Chief, Thoracic, Vascular,
Radiology, and Neuroanesthesia, Department of Anesthesia, Critical Care, and Pain Medicine,
Massachusetts General Hospital, Boston, Massachusetts

Gilman B. Allen, MD

Associate Professor of Medicine, Director of Medical Intensive Care Unit, Pulmonary and Critical
Care Medicine, University of Vermont College of Medicine; Attending Physician, Pulmonary and
Critical Care Medicine, Fletcher Allen Health Care, Burlington, Vermont

Michael N. Andrawes, MD
Instructor, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General
Hospital/Harvard Medical School, Boston, Massachusetts

Abbas Ardehali, MD, FACS
Professor of Surgery and Medicine, Division of Cardiothoracic Surgery, UCLA; Director of Heart,
Lung, and Heart/Lung Transplant Programs, Division of Cardiothoracic Surgery, Ronald Reagan
UCLA Medical Center; Chief, Division of Cardiac Surgery, Veterans Affairs Greater Los Angeles
Healthcare System, Los Angeles, California

Aranya Bagchi, MBBS
Clinical Fellow in Anesthesia, Department of Anesthesia, Critical Care and Pain Medicine,
Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts

Keith Baker, MD, PhD
Assistant Professor of Anesthesia, Harvard Medical School; Assistant Anesthetist, Department of
Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston,
Massachusetts

Arna Banerjee, MD
Assistant Professor of Anesthesiology and Surgery, Department of Anesthesiology and Critical
Care, Vanderbilt University Medical Center, Nashville, Tennessee

vii

viii CONTRIBUTORS
Carolyn E. Bekes, MD, MHA, FCCM
Professor of Medicine, Cooper Medical School of Rowan University; Chief Medical Officer,
Cooper University Hospital, Camden, New Jersey

William J. Benedetto, MD
Anesthesia Instructor, Department of Anesthesia, Critical Care, and Pain Management,
Massachusetts General Hospital, Boston, Massachusetts

Pavan K. Bendapudi, MD
Clinical Fellow, Pathology Department, Harvard Medical School; Clinical Fellow, Blood
Transfusion Service, Brigham and Women’s Hospital, Boston, Massachusetts

John R. Benjamin, MD, MSc
Fellow in Critical Care Medicine, Department of Anesthesia, Critical Care, and Pain
Management, Massachusetts General Hospital, Boston, Massachusetts; Commander,
Medical Corps, United States Navy, Walter Reed Memorial Military Medical Center, Bethesda,
Maryland

Philip E. Bickler, MD, PhD
Professor, Department of Anesthesia and Perioperative Care, UCSF, San Francisco, California

Luca M. Bigatello, MD
Adjunct Professor of Anesthesiology, Tufts University School of Medicine, Boston; Director,
Surgical Critical Care, Department of Anesthesiology and Pain Medicine, St. Elizabeth’s Medical
Center, Brighton, Massachusetts

Edward A. Bittner, MD, PhD
Assistant Professor of Anesthesia, Harvard Medical School; Associate Director, Surgical
Intensive Care Unit, Program Director, Critical Care-Anesthesiology Fellowship, Department of

Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston,
Massachusetts

Brad W. Butcher, MD
Fellow, Department of Internal Medicine, Division of Nephrology, UCSF Medical Center, San
Francisco, California

Michael E. Canham, MD
Associate Professor of Medicine, National Jewish Medical and Research Center, University of
Colorado Health Sciences Center, Denver, Colorado

William E. Charash, MD, PhD
Associate Professor, Surgery, Chief, Division of Trauma, Burns, and Surgical Critical Care,
University of Vermont College of Medicine, Burlington, Vermont

Jonathan E. Charnin, MD
Instructor, Harvard Medical School; Assistant Residency Program Director, Department of
Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston,
Massachusetts

Hovig V. Chitilian, MD
Instructor in Anesthesia, Harvard Medical School; Staff Anesthesiologist, Department of
Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston,
Massachusetts

Alexandra F.M. Cist, MD
Instructor in Medicine, Harvard Medical School; Assistant in Medicine, Pulmonary and Critical
Care Unit, Massachusetts General Hospital, Boston, Massachusetts

CONTRIBUTORS ix

Jaina Clough, MD
Assistant Professor, Primary Care Internal Medicine, University of Vermont College of Medicine/
Fletcher Allen Health Care, Burlington, Vermont

J. Perren Cobb, MD
Associate Professor, Departments of Anesthesia and Surgery, Harvard University; Director,
Critical Care Center, Vice-Chair for Critical Care, Department of Anesthesia, Critical Care, and
Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts

Elizabeth Cox, MD
Anesthesia Resident, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts
General Hospital, Boston, Massachusetts

Bruce A. Crookes, MD, FACS
Associate Professor of Surgery, Department of Surgery, Medical University of South Carolina,
Charleston, South Carolina

Harold L. Dauerman, MD
Professor of Medicine, University of Vermont College of Medicine; Director, Cardiovascular
Catheterization Laboratories, Fletcher Allen Health Care, Burlington, Vermont

Marc A. DeMoya, MD
Assistant Professor of Surgery, Division of Trauma, Emergency Surgery, and Surgical
Critical Care, Massachusetts General Hospital/Harvard Medical School, Boston,
Massachusetts

Anne E. Dixon, MA, BM, BCh
Associate Professor, Department of Medicine, University of Vermont College of Medicine,

Burlington, Vermont

Cameron Donaldson, MD
Clinical Instructor, University of Vermont College of Medicine; Fellow, Cardiology, Fletcher Allen
Health Care, Burlington, Vermont

Shawn P. Fagan, MD
Medical Director, Division of Burns, Massachusetts General Hospital and Shriners Hospital for
Children, Boston, Massachusetts

Peter J. Fagenholz, MD
Attending Surgeon, Department of Surgery, Division of Trauma, Emergency Surgery, and Critical
Care, Massachusetts General Hospital; Instructor in Surgery, Harvard Medical School, Boston,
Massachusetts

Corey R. Fehnel, MD
Clinical Fellow, Neurology, Harvard Medical School; Neurocritical Care Fellow, Massachusetts
General Hospital, Boston, Massachusetts

Michael G. Fitzsimons, MD, FCCP
Director, Division of Cardiac Anesthesia, Assistant Professor, Department of Anesthesia, Critical
Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts

Zechariah S. Gardner, MD
Assistant Professor, Primary Care Internal Medicine, University of Vermont College of Medicine;
Attending Physician, Hospitalist Medicine, Primary Care Internal Medicine, Fletcher Allen Health
Care, Burlington, Vermont


x CONTRIBUTORS

Edward E. George, MD, PhD
Medical Director, Post Anesthesia Care Units, Assistant Anesthetist, Department of Anesthesia,
Critical Care, and Pain Management, Massachusetts General Hospital, Boston, Massachusetts;
Assistant Professor in Anesthesia, Harvard Medical School, Boston, Massachusetts;
Commander, Medical Corps, United States Navy, Walter Reed Memorial Military Medical Center,
Bethesda, Maryland

Matthew P. Gilbert, DO, MPH
Assistant Professor of Medicine, Endocrinology, Diabetes, and Metabolism, University of
Vermont College of Medicine, Burlington, Vermont

Jeremy Goverman, MD, FACS
Instructor, Department of Surgery, Harvard Medical School; Assistant in Surgery, Division of
Burns, Massachusetts General Hospital; Medical Staff, Burns, Shriners Hospital for Children,
Boston, Massachusetts

Christopher Grace, MD, FACP
Director, Infectious Diseases Unit, Fletcher Allen Health Care; Professor of Medicine, Department
of Medicine, University of Vermont College of Medicine, Burlington, Vermont

Michael A. Gropper, MD, PhD
Professor and Executive Vice Chairperson, Department of Anesthesia and Perioperative Care,
Director, Critical Care Medicine, Investigator, Cardiovascular Research Institute, UCSF,
San Francisco, California

Jennifer M. Hall, DO
Fellow, Geriatric Psychiatry, Duke University Hospital, Durham, North Carolina

Michael E. Hanley, MD
Professor of Medicine, Division of Pulmonary and Critical Care Medicine, University of Colorado

Denver Health Sciences Center; Associate Director of Medicine, Denver Health Medical Center,
Denver, Colorado

C. William Hanson, III, MD
Professor of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia,
Pennsylvania

John E. Heffner, MD
Professor of Medicine, Oregon Health and Science University; William M. Garnjobst Chair,
Department of Medicine, Providence Portland Medical Center, Attending Physician, The Oregon
Clinic, Portland, Oregon

David C. Hooper, MD
Professor of Medicine, Harvard Medical School; Associate Chief, Division of Infectious Diseases,
Chief, Infection Control Unit, Massachusetts General Hospital, Boston, Massachusetts

Christopher D. Huston, MD
Associate Professor, Infectious Diseases, Departments of Medicine, and Microbiology and
Molecular Genetics, University of Vermont College of Medicine, Burlington, Vermont

James L. Jacobson, MD
Associate Professor, Psychiatry, University of Vermont College of Medicine; Director, Outpatient
Psychiatry Department and Psychopharmacology Clinic, Fletcher Allen Health Care, Burlington,
Vermont


CONTRIBUTORS xi

Daniel W. Johnson, MD
Instructor, Harvard Medical School; Department of Anesthesia, Critical Care, and Pain Medicine,

Massachusetts General Hospital, Boston, Massachusetts

Christine Haas Jones, MD
Assistant Professor of Medicine, University of Vermont College of Medicine, Burlington,
Vermont

David A. Kaminsky, MD
Associate Professor, Pulmonary and Critical Care Medicine, University of Vermont College of
Medicine; Attending Physician, Pulmonary and Critical Care Medicine, Fletcher Allen Health Care,
Burlington, Vermont

George Kasotakis, MD
Instructor in Surgery, Harvard Medical School; Acute Care Surgery Fellow, Division of Trauma,
Emergency Surgery, and Surgical Critical Care, Massachusetts General Hospital, Boston,
Massachusetts

Dinkar Kaw, MD
Associate Professor of Medicine, Division of Nephrology, Department of Medicine, University of
Toledo College of Medicine, Toledo, Ohio

David R. King, MD, FACS
Instructor, Department of Surgery, Harvard Medical School; Attending Surgeon, Division of
Trauma, Emergency Surgery, and Surgical Critical Care, Massachusetts General Hospital,
Boston, Massachusetts

Themistoklis Kourkoumpetis, MD
Postdoctoral Research Fellow, Division of Infectious Diseases, Massachusetts General Hospital/
Harvard Medical School, Boston, Massachusetts

Asheesh Kumar, MD

Assistant Professor, Department of Anesthesiology, Uniformed Health Sciences University,
Bethesda, Maryland

David J. Kuter, MD, DPhil
Professor of Medicine, Harvard Medical School; Chief of Hematology, Department of Medicine,
Massachusetts General Hospital, Boston, Massachusetts

Stephen E. Lapinsky, MBBCh, MSc, FRCPC
Professor, Department of Medicine, University of Toronto; Site Director, Intensive Care Unit,
Mount Sinai Hospital, Toronto, Ontario, Canada

Jack L. Leahy, MD
Professor of Medicine and Chief of Endocrinology, Diabetes, and Metabolism, University of
Vermont College of Medicine, Burlington, Vermont

Kay B. Leissner, MD, PhD
Instructor, Department of Anesthesia, Harvard Medical School; Adjunct Assistant Professor
of Anesthesiology, Boston University School of Medicine; Adjunct Assistant Professor of
Anesthesiology, Tufts University School of Medicine, Boston; Chief, Anesthesiology Service,
Veterans Affairs Boston Healthcare System, West Roxbury, Massachusetts

Martin M. LeWinter, MD
Professor, Medicine and Molecular Physiology and Biophysics, University of Vermont College of
Medicine; Attending Physician, Cardiology, Fletcher Allen Health Care, Burlington, Vermont


xii CONTRIBUTORS
Stuart L. Linas, MD
Rocky Mountain Kidney Professor of Renal Research and Professor of Medicine, University of
Colorado School of Medicine; Chief of Nephrology, Denver Health Sciences Center, Denver,

Colorado

Kathleen D. Liu, MD, PhD, MAS
Assistant Professor, Departments of Medicine and Anesthesia, UCSF, San Francisco, California

Madison Macht, MD
Fellow, Pulmonary Sciences and Critical Care Medicine, University of Colorado Denver, Aurora,
Colorado

Theodore W. Marcy, MD, MPH
Professor Emeritus of Medicine, Pulmonary Disease and Critical Care Medicine, University of
Vermont College of Medicine, Burlington, Vermont

Annis Marney, MD, MSCI
Assistant Professor of Medicine, Division of Diabetes, Endocrinology, and Metabolism,
University of Vermont College of Medicine; Attending Physician, Fletcher Allen Health Care,
Burlington, Vermont

Jenny L. Martino, MD, MSPH
Attending Physician, Pulmonary and Critical Care Medicine, PeaceHealth Medical Group,
PeaceHealth Southwest Medical Center, Vancouver, Washington

Philip McArdle, MB, BCh, BAO, FFARCSI
Associate Professor, Department of Anesthesiology, University of Alabama at Birmingham,
Birmingham, Alabama

David W. McFadden, MD, FACS
Professor and Chair, Department of Surgery, University of Connecticut School of Medicine,
Farmington, Connecticut

Ursula McVeigh, MD
Assistant Professor, Department of Family Medicine, University of Vermont College of
Medicine; Interim Director, Palliative Care Service, Fletcher Allen Health Care, Burlington,
Vermont

Ali Y. Mejaddam, MD
Trauma Research Fellow, Division of Trauma, Emergency Surgery, and Surgical Critical Care,
Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts

Prema R. Menon, MD
Clinical Instructor, Pulmonary/Critical Care, University of Vermont College of Medicine/Fletcher
Allen Health Care, Burlington, Vermont

David W. Miller, MD
Assistant Professor, Department of Anesthesiology, Division of Critical Care and Perioperative
Medicine, Co-Director, Neurosciences Intensive Care Unit, University of Alabama at Birmingham,
Birmingham, Alabama

Benoit Misset, MD
Professor of Intensive Care Medicine, Paris Descartes University; Head of Medical Surgical
Intensive Care Unit, Paris Saint-Joseph Hospital Network, Paris, France


CONTRIBUTORS xiii

Sarah Mooney, MBBCh, MRCP
Fellow, Infectious Diseases, University of Vermont College of Medicine/Fletcher Allen Health
Care, Burlington, Vermont

Amy E. Morris, MD

Assistant Professor, Division of Pulmonary and Critical Care Medicine, University of Washington,
Seattle, Washington

Marc Moss, MD
Roger S. Mitchell Professor of Medicine, Division of Pulmonary Sciences and Critical Care
Medicine, University of Colorado Denver, Aurora, Colorado

Eleftherios E. Mylonakis, MD, PhD, FIDSA
Associate Professor of Medicine, Division of Infectious Diseases, Massachusetts General
Hospital/Harvard Medical School, Boston, Massachusetts

Claus U. Niemann, MD
Professor of Anesthesia and Surgery, Department of Anesthesia and Perioperative Care, and
Department of Surgery, Division of Transplantation, UCSF, San Francisco, California

Cindy Noyes, MD
Assistant Professor of Medicine, Infectious Disease, Fletcher Allen Health Care/University of
Vermont College of Medicine, Burlington, Vermont

Ala Nozari, MD, PhD
Assistant Professor of Anesthesia, Harvard Medical School; Assistant Anesthetist, Department of
Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston,
Massachusetts

Islem Ouanes, MD
Assistant Professor of Intensive Care Medicine, Intensive Care Unit, University Hospital Fattouma
Bourguiba, University of Monastir, Monastir, Tunisia

Pratik Pandharipande, MBBS, MSCI
Associate Professor of Anesthesiology, Department of Anesthesiology and Critical Care,

Vanderbilt University Medical Center and Tennessee Valley Healthcare System, Nashville,
Tennessee

Manuel Pardo, Jr., MD
Professor and Vice Chair for Education, Department of Anesthesia and Perioperative Care, UCSF,
San Francisco, California

Kapil Patel, MD
Clinical Assistant Professor of Medicine, Pulmonary and Critical Care Medicine, University of
Maryland Medical Center, Baltimore, Maryland; Attending Physician, Pulmonary and Critical Care
Medicine, Upper Chesapeake Medical Center, Bel-Air, Maryland

William Peery, MD
Assistant Professor of Surgery, Department of Surgery, West Virginia University, Charleston,
West Virginia

Sarah Pesek, MD
Clinical Instructor, Surgery, University of Vermont College of Medicine; Surgical Resident,
Fletcher Allen Health Care, Burlington, Vermont

Kristen K. Pierce, MD
Assistant Professor of Medicine, Infectious Disease, University of Vermont College of Medicine/
Fletcher Allen Health Care, Burlington, Vermont


xiv CONTRIBUTORS
Jean-Franc¸ois Pittet, MD
Director, Division of Critical Care and Perioperative Medicine, Professor and Vice-Chair,
Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, Alabama

Louis B. Polish, MD
Associate Professor of Medicine, Division of Infectious Diseases, Director, Internal Medicine
Clerkship, University of Vermont College of Medicine, Burlington, Vermont

Nitin Puri, MD, FACP
Medical Intensivist, Pulmonary/Critical Care, Inova Fairfax Hospital, Falls Church, Virginia

Allan Ramsay, MD
Professor Emeritus, Department of Family Medicine, University of Vermont College of Medicine,
Burlington, Vermont; Interim Medical Director, Hospice of the Champlain Valley, Colchester,
Vermont

Daniel Saddawi-Konefka, MD, MBA
Clinical Fellow, Department of Anesthesia, Harvard Medical School; Resident, Department of
Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston,
Massachusetts

Neeraj K. Sardana, MD
Fellow, Department of Gastroenterology and Hepatology, University of Vermont College of
Medicine/Fletcher Allen Health Care, Burlington, Vermont

Richard H. Savel, MD, FCCM
Associate Professor of Clinical Medicine and Neurology, Albert Einstein College of Medicine;
Medical Co-Director, Surgical Intensive Care Unit, Montefiore Medical Center, Bronx,
New York

Ulrich H. Schmidt, MD, PhD
Associate Professor, Department of Anesthesia, Critical Care, and Pain Medicine, Harvard
Medical School; Medical Director, Surgical Intensive Care Unit and Respiratory Care Services,
Massachusetts General Hospital, Boston, Massachusetts

Lynn M. Schnapp, MD
Professor, Pulmonary and Critical Care Medicine and Center for Lung Biology, University of
Washington; Attending Physician, Medical and Trauma Intensive Care Unit, Harborview Medical
Center, Seattle, Washington

Alison Schneider, MD
Clinical Instructor and Fellow, Endocrinology, Diabetes, and Metabolism, University of Vermont
College of Medicine, Burlington, Vermont

Joel J. Schnure, MD
Associate Professor, University of Vermont College of Medicine; Co-Director, Division of
Endocrinology, Diabetes, and Metabolism, Fletcher Allen Health Care; Burlington, Vermont

Lee H. Schwamm, MD, FAHA
Vice Chairman, Department of Neurology, C. Miller Fisher Endowed Chair and Director,
TeleStroke and Acute Stroke Services, Massachusetts General Hospital; Professor of Neurology,
Harvard Medical School, Boston, Massachusetts

Joseph I. Shapiro, MD
Dean, Marshall University Joan C. Edwards School of Medicine, Huntington, West Virginia


CONTRIBUTORS xv

Shailendra Sharma, MD
Academic Hospitalist, Denver Hospital and Health Authority; Nephrology Fellow, University of
Colorado School of Medicine, Denver, Colorado

Kenneth Shelton, MD

Clinical Fellow in Anesthesia, Department of Anesthesia, Critical Care, and Pain Medicine,
Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts

Erica S. Shenoy, MD, PhD
Research Fellow in Medicine, Harvard Medical School; Clinical and Research Fellow, Division of
Infectious Diseases, Infection Control Unit, Massachusetts General Hospital, Boston,
Massachusetts

David Shimabukuro, MDCM
Medical Director, Department of Anesthesia and Perioperative Care, UCSF, San Francisco,
California

Stuart F. Sidlow, MD
Attending Anesthesiologist, Department of Anesthesiology, Pennsylvania Hospital, Philadelphia,
Pennsylvania

Aaron B. Skolnik, MD
Clinical Fellow, Department of Medical Toxicology, Banner Good Samaritan Medical Center,
Phoenix, Arizona

Peter S. Spector, MD
Professor of Medicine, Department of Medicine, University of Vermont College of Medicine;
Director, Cardiac Electrophysiology, Attending Physician, Cardiology, Fletcher Allen Health Care,
Burlington, Vermont

Antoinette Spevetz, MD, FCCM, FACP
Associate Professor of Medicine, Cooper Medical School of Rowan University; Associate
Director, MSICU for Operations, Director, Intermediate Care Unit, Section of Critical Care
Medicine, Cooper University Hospital, Camden, New Jersey

Renee D. Stapleton, MD, PhD
Assistant Professor, Medicine, Pulmonary, and Critical Care Medicine, University of Vermont
College of Medicine, Burlington, Vermont

Scott C. Streckenbach, MD
Assistant Professor, Anesthesia, Massachusetts General Hospital/Harvard Medical School,
Boston, Massachusetts

Benjamin T. Suratt, MD
Associate Professor of Medicine and Associate Chief, Division of Pulmonary and Critical Care
Medicine, University of Vermont College of Medicine; Attending Physician, Department of
Medicine, Fletcher Allen Health Care, Burlington, Vermont

Lynda S. Tilluckdharry, MB, BCh, BAO, LRCP&SI
Consultant, Rheumatology and Immunology, Cross Crossing Medical Center, San Fernando,
Trinidad and Tobago, West Indies

Gwendolyn M. van der Wilden, MSc
Clinical Research Fellow, Surgery, Division of Trauma, Emergency Surgery, and Surgical Critical
Care, Massachusetts General Hospital, Boston, Massachusetts


xvi CONTRIBUTORS
Susan A. Vassallo, MD
Assistant Professor of Anesthesia, Harvard Medical School; Anesthetist, Department of
Anesthesia, Critical Care, and Pain Management, Massachusetts General Hospital, Boston,
Massachusetts

George C. Velmahos, MD, PhD, MSEd
John Francis Burke Professor of Surgery, Harvard Medical School; Chief, Division of Trauma,

Emergency Surgery, and Surgical Critical Care, Massachusetts General Hospital, Boston,
Massachusetts

Joseph L. Weidman, MD
Anesthesiology Resident, Department of Anesthesiology, Critical Care, and Pain Medicine,
Massachusetts General Hospital, Boston, Massachusetts

Jeanine P. Wiener-Kronish, MD
Henry Isaiah Dorr Professor of Research and Teaching in Anesthetics and Anesthesia, Harvard
Medical School; Anesthetist-in-Chief, Massachusetts General Hospital, Boston, Massachusetts

Susan R. Wilcox, MD
Staff Physician, Department of Anesthesia, Critical Care, and Pain Medicine, and Department of
Emergency Medicine, Massachusetts General Hospital, Boston, Massachusetts

Chad Wilson, MD, MPH
Assistant Professor of Surgery, New York University School of Medicine, New York, New York

Marie E. Wood, MD
Professor of Medicine, University of Vermont College of Medicine, Burlington, Vermont

Daniel Yagoda, MPH
Health Engineer, Critical Care Center, Massachusetts General Hospital, Boston, Massachusetts

Jon (Kai) Yamaguchi, MD, FACS
Assistant Professor of Surgery, University of Vermont College of Medicine; Chief, Division of
Transplant Surgery, Fletcher Allen Health Care, Burlington, Vermont

Michael Young, MD
Professor of Medicine, Pulmonary and Critical Care, Wake Forest University; Medical Director

and Attending Physician, Intermediate Care and Medical Intensive Care Unit, Wake Forest/Baptist
Medical Center, Winston-Salem, North Carolina

Pierre Znojkiewicz, MD
Clinical Instructor and Fellow, Cardiology, University of Vermont College of Medicine, Burlington,
Vermont


PREFACE
Over the course of the past five editions of Critical Care Secrets, critical care medicine has
become increasingly complex. The fundamentals and clinical skills required to care for
critically ill patients continue to transcend subspecialties, so in this edition we have again
included chapters from a wide range of specialists, including pulmonologists, surgeons,
anesthesiologists, psychiatrists, pharmacists, and infectious disease experts. We have
asked these experts to pose the key questions in critical care and formulate the answers so
practitioners can identify effective solutions to their patients’ medical and ethical problems.
A broad understanding of anatomy, physiology, immunology, and inflammation is
fundamentally important to effectively care for critically ill patients. For example, it is hard
to imagine understanding the principles of mechanical ventilation without being aware of
the principles of gas and fluid flow, pulmonary mechanics, and electronic circuitry.
Accordingly, the authors have incorporated these key elements into this edition. In addition,
critical care medicine requires knowledge of protocols and guidelines that are continuously
evolving and that increasingly dictate best practices.
In this fifth edition of Critical Care Secrets, we have again been fortunate to have many
of the leaders in critical care contribute chapters in their areas of expertise. In addition to
substantially revising and updating chapters from the previous edition, we have included
new chapters on timely topics such as intensive care unit ultrasound, extracorporeal
membrane oxygenation, influenza, disaster medicine, arterial and central venous catheters,
the immunocompromised host, toxic alcohol and cardiovascular drug poisoning, palliative
care, and organ donation.

We sincerely thank all of the authors who contributed their time and expertise to this
endeavor. We believe they have captured the essence of critical care medicine and have
presented it in a format that will be useful to everyone, from students to experienced
clinicians.
Polly E. Parsons, MD
Jeanine P. Wiener-Kronish, MD

xvii


TOP 100 SECRETS
These secrets are 100 of the top board alerts. They summarize the
concepts, principles, and most salient details of critical care medicine.
1. Elevated lactate levels suggest tissue hypoperfusion, and normal lactate clearance is
suggestive of adequate fluid resuscitation.
2. Always assume that even a single episode of hypotension in a trauma patient is due to
bleeding, and proceed accordingly.
3. Good cardiopulmonary resuscitation can make a difference for a successful resuscitation
from cardiac arrest. Know and perform it well.
4. Time to defibrillation is the most important factor in a return of spontaneous circulation
from ventricular tachycardia and/or ventricular fibrillation.
5. Pulse oximetry is good for continuous monitoring, but arterial blood gases (ABGs) are
best for diagnosis and acute management. If oximetry does not fit the clinical picture,
obtain an ABG.
6. Use the alveolar gas equation to help understand mechanisms of hypoxemia.
7. Hemodynamic monitoring assesses whether the circulatory system has adequate
performance to supply oxygen and sustain the “fire of life.” Monitoring provides data to
guide therapy but is not therapeutic.
8. There is no proved benefit to colloid over crystalloid in acute resuscitation.
9. Starting enteral nutrition early in critically ill patients increased survival.

10. Enteral feeding in patients with shock is acceptable after the patient is resuscitated and
hemodynamically stable, even if the patient is receiving stable lower doses of
vasopressors.
11. The primary indications for mechanical ventilation are inadequate oxygenation, inadequate
ventilation, and elevated work of breathing.
12. Low tidal volume mechanical ventilation can lead to improved outcomes in the patient with
acute respiratory distress syndrome.
13. Daily weaning assessments improve patient outcomes.
14. The rate of central venous catheter–related bloodstream infections can be reduced through
a combination of the use of maximal sterile barrier precautions, 2% chlorhexidine-based
antiseptic, centralization of line insertion supplies, and daily evaluation of the need for
continued central access.
15. Subclavian venous catheters have the lowest risk of bloodstream infection.

1


2 TOP 100 SECRETS
16. Lung sliding on ultrasound examination effectively rules out pneumothorax at the site of
the transducer.
17. Extracorporeal membrane oxygenation can be used successfully in patients with
respiratory failure in whom low tidal volume ventilation is failing.
18. Nonrecognition of an esophageal intubation leads to death; direct visual confirmation
or detection of carbon dioxide must be done to confirm the proper location of an
endotracheal tube.
19. If a tracheostomy tube falls out of its stoma within the first 1 to 5 days of placement, do not
attempt to reinsert it blindly. Perform translaryngeal intubation instead because blind
attempts at reinsertion misplace the tube into a paratracheal track, compress the trachea,
and cause asphyxia.
20. Any airway or stomal bleeding that develops more than 48 hours after tracheotomy should

suggest the possibility of a tracheoarterial fistula, which develops as a communication
between the trachea and a major intrathoracic artery.
21. A retrospective study showed that positive pressure ventilation (PPV) does not influence
the rate of recurrent pneumothorax or chest tube placements after removal. Consequently,
presence of mechanical PPV is not an indication to leave a chest tube in place.
22. Chest physiotherapy appears to be as effective as bronchoscopy in treating atelectasis,
although bronchoscopy has a role in retained, inspissated secretions or foreign bodies.
23. Pulmonary artery line placement in patients with a newly implanted (less than 3 months)
implantable cardioverter defibrillator or pacemaker is associated with high risk of lead
dislodgment, especially if there is a coronary sinus lead.
24. Intraaortic balloon pumps should be considered in patients who may benefit from
increased diastolic pressures (persistent refractory angina, cardiovascular compromise
from myocardial ischemia/infarction) or decreased afterload (acute mitral regurgitation,
cardiogenic shock).
25. Clinical judgment should supplement severity of illness scores in defining patients with
severe community-acquired pneumonia.
26. The use of clinical criteria alone will lead to the overdiagnosis of ventilator-associated
pneumonia.
27. A normal PCO2 in acute asthma is a warning sign of impending respiratory failure.
28. Noninvasive mechanical ventilation reduces the need for intubation in patients with a
chronic obstructive pulmonary disease exacerbation and impending respiratory failure.
29. Chronic hypoxemia is the most common cause of pulmonary hypertension.
30. Patients with acute lung injury and acute respiratory distress syndrome die of multiorgan
dysfunction far more frequently than they do of refractory hypoxemia.
31. For most patients, bronchial artery embolization is the treatment of choice to stop
hemorrhaging in massive hemoptysis.


TOP 100 SECRETS 3
32. Because death from massive hemoptysis is more commonly caused by asphyxiation than

exsanguination, it is important to emergently maintain airway patency and protect the
nonbleeding lung.
33. Deep venous thrombosis and pulmonary embolism are common and often
underdiagnosed in critically ill patients.
34. The key to treating heart failure is determining the cause, that is, reduced ejection fraction,
normal/preserved ejection fraction, restrictive cardiomyopathy, hypertrophic
cardiomyopathy, or right ventricular failure.
35. The best clinical guide to help in choosing which treatment is appropriate for the critically ill
patient with heart failure is to assess volume and perfusion status.
36. Acute myocardial infarction, complicated by out-of-hospital cardiac arrest, has a very high
mortality, and hypothermia may improve chances for survival and neurologic recovery.
37. It is important to distinguish hemodynamically unstable arrhythmias that need immediate
cardioversion/defibrillation from other more stable rhythms.
38. When managing acute aortic dissection, adequate beta blockade must be established
before the initiation of nitroprusside to prevent propagation of the dissection from a reflex
increase in cardiac output.
39. Pulsus paradoxus is when there is respiratory variation on arterial waveform seen during
pericardial tamponade of >10 mm Hg.
40. Severe sepsis ¼ sepsis plus acute organ dysfunction.
41. Early diagnosis and therapeutic interventions in patients with severe sepsis or septic shock
are associated with better outcomes.
42. Between 60% and 80% of cases of endocarditis result from streptococcal infection.
Staphylococcus aureus tends to be the most common etiologic agent of infective
endocarditis in intravenous (IV) drug users.
43. Streptococcus pneumoniae remains the most common cause of community-acquired
bacterial meningitis, and treatment directed to this should be included in the initial empiric
regimen.
44. Most patients do not require computed tomographic scan before lumbar puncture;
however, signs and symptoms that suggest elevated intracranial pressure should prompt
imaging. These include new-onset neurologic deficits, new-onset seizure, and papilledema.

Severe cognitive impairment and immune compromise are also conditions that warrant
consideration for imaging.
45. If you suspect disseminated fungal infection, do not wait for cultures to treat.
46. Reducing multidrug-resistant bacteria can only be accomplished by using fewer
antibiotics, not more.
47. Clinical or laboratory identification of an unusual pathogen (i.e., anthrax, smallpox, plague)
should raise suspicion for a biologic attack.


4 TOP 100 SECRETS
48. Pain disproportionate to physical findings; skin changes including hemorrhage, sloughing, or
anesthesia; rapid progression; crepitus; edema beyond the margin of erythema; and systemic
involvement should prompt intense investigation for deep infection and involvement of
surgical consultants as needed in the case of necrotizing fasciitis or gas gangrene.
49. During influenza season all persons admitted to the intensive care unit (ICU) with
respiratory illness should be presumed to have influenza and be tested and treated.
50. Asplenic individuals are at risk for infection with encapsulated organism.
51. The greatest degree of immunosuppression in solid organ transplant recipients is in the 1
to 6 months after transplantation.
52. Severe hypertension in absence of end organ damage can be safely treated outside
the setting of intensive care and reduction in blood pressure be achieved gently over
hours to days.
53. The serum creatinine level may not change much during acute renal failure in patients with
decreased muscle mass.
54. In the analysis of acid-base disorders, a normal serum pH does not imply that there is not
an acid-base disorder; rather it points to mixed disorder.
55. Serum magnesium level should be checked and corrected, if low, in patients with refractory
hypokalemia.
56. Overly rapid correction of hyponatremia or hypernatremia can result in devastating
long-term neurologic sequelae.

57. If a patient has neurologic symptoms associated with hyponatremia, one of the immediate
goals of therapy should be correction of serum sodium to a safe level.
58. Be systematic in your workup of gastrointestinal tract bleeding. Follow an algorithm.
59. In a patient with acute pancreatitis, make sure the patient’s fluid is replenished with an
adequate amount of IV fluid. This is as important as, if not more important than, the other
facets of treatment, including pain control, nutritional support, correcting electrolyte
abnormalities, treating infection (if present), and treating the underlying cause.
60. Steroids should be considered for the treatment of severe alcoholic hepatitis as defined by
a Maddrey’s discriminate score 32.
61. Abdominal compartment syndrome is an underappreciated diagnosis.
62. This is no secret—we all share the responsibility for reducing nosocomial infections.
63. Worsening confusion or a new impairment in mental state during treatment of diabetic
ketoacidosis or hyperosmolar hyperglycemic state is life-threatening cerebral edema until
proved otherwise.
64. Administering insulin without adequate fluid replacement during treatment of diabetic
ketoacidosis or hyperosmolar hyperglycemic state can lead to profound hypotension,
shock, or cardiovascular collapse.


TOP 100 SECRETS 5
65. An IV insulin infusion is the safest and most effective way to treat hyperglycemia in critically
ill patients.
66. If the blood pressure of an ICU patient with septic shock responds poorly to repeated fluid
boluses and vasopressors, hydrocortisone should be given regardless of cortisol levels.
67. In most cases you do not need to treat nonthyroidal illness syndrome with levothyroxine
despite low thyroxine, triiodothyronine, and thyroid-stimulating hormone levels; instead
follow expectantly, and recheck laboratory values in 4 to 6 weeks.
68. Stable anemia is well tolerated in critically ill patients. Transfuse blood products only when
necessary or if hemoglobin level drops below 7 gm/dL.
69. Although disseminated intravascular coagulation typically presents with bleeding or

laboratory abnormalities suggesting deficient hemostasis, hypercoagulability and
accelerated thrombin generation actually underlie the process.
70. Surgery for cord compression can keep people ambulatory longer than radiation alone.
71. For a neutropenic fever, draw cultures, give broad-spectrum antibiotics, then complete the
workup.
72. In a patient in the ICU who is seen with multiorgan failure or a clinical picture resembling
fulminant sepsis, consider the diagnosis of systemic lupus erythematosus or vasculitis.
73. Respiratory pattern, autonomic functions, and brain stem reflexes are critical in identifying
the cause of coma and should be recorded in all patients.
74. No ancillary test can replace an experienced clinical examination for determination of brain
death.
75. The mainstay of treatment for status epilepticus includes stabilizing the patient, controlling
the seizures, and treating the underlying cause.
76. ICU admission, invasive hemodynamic monitoring, and respiratory support with frequent
vital capacity measurements are keys to following patients with Guillain-Barre´ syndrome.
77. Tachypnea is often the first sign of respiratory muscle weakness. Respiratory muscle
strength is ideally measured by maximum inspiratory flow and vital capacity (VC) in
patients with myasthenia gravis. A quick surrogate for forced VC is to ask the patient to
count to the highest number possible during one expiration.
78. Benzodiazepines are the preferred agents for the treatment of alcohol withdrawal.
79. Time should not be wasted pursuing radiographic confirmation when a tension
pneumothorax is suspected in a hemodynamically unstable patient. Either formal tube
thoracostomy should be immediately performed or an Angiocath inserted into the second
intercostal space along the midclavicular line.
80. The condition of a significant number of patients with flail chest and/or pulmonary
contusion can be safely and effectively managed without intubation by using aggressive
pulmonary care, including face-mask oxygen, continuous positive airway pressure, chest
physiotherapy, and pain control.

6 TOP 100 SECRETS
81. The model for end-stage liver disease (MELD) calculates the severity of liver disease.
82. Delirium is a disturbance of consciousness with inattention, accompanied by a change in
cognition or perceptual disturbances that develop over a short period of time, fluctuate over
days, and remain underdiagnosed.
83. Therapeutic hypothermia (temperature 30 -34 C) improves neurologic outcomes in
comatose survivors of cardiac arrest.
84. Heat stroke is a true medical emergency requiring immediate action: Delay in cooling
increases mortality.
85. When caring for a critically ill poisoned patient, the diagnostic and therapeutic interventions
should be started on the basis of the clinical presentation, with use of the history, the
physical examination, and recognition of toxidromes.
86. Syrup of ipecac and gastric lavage have no role in the routine management of the poisoned
patient.
87. Oral or IV N-acetylcysteine should be administered promptly to any patient with suspected
or confirmed acetaminophen toxicity.
88. Patients with methanol and ethylene glycol ingestions present with an osmolal gap, which
closes with metabolism and develops an anion gap acidosis. Isopropanol toxicity begins
with an osmolal gap but is not metabolized to an anion gap.
89. Patients with toxic alcohol ingestion and any vision disturbance, severe metabolic acidosis,
or renal failure should undergo urgent hemodialysis.
90. The treatment of choice for calcium channel blocker toxicity is hyperinsulinemiaeuglycemia therapy to maximize glucose uptake into cardiac myocytes.
91. Neuroleptic malignant syndrome can occur at any age in either sex with exposure to any
antipsychotic medication.
92. Although radiologic investigations and drug treatment may carry some risk of harm to the
fetus, necessary tests and treatment should not be avoided in the critically ill mother.
93. Patients and their families are the experts on the patient’s goals and values, and clinicians
are the experts on determining which clinical interventions are indicated to try to achieve
reasonable clinical goals.
94. Timely ethics consultation in the ICU may mitigate conflict and reduce ICU length of stay,

hospital length of stay, ventilator days, and costs.
95. Only discuss treatment choices after the patient or family has been updated on medical
condition, prognosis, and possible outcomes and once overall goals of medical care are
agreed on.
96. Family conferences are more successful when providers listen more and talk
less. Encourage the family to discuss their understanding of illness, their emotions,
and who the patient is as a person. Then respond with statements of support and
understanding.


TOP 100 SECRETS 7
97. All patients with impending brain death or withdrawal of care should be screened for the
possibility of organ donation.
98. The gap between those patients awaiting a transplant and those donating organs is
widening exponentially—the vast majority of those on the transplant list will die waiting.
99. The hospital systems investing today in advanced informatics, automated decision
analysis, telemedicine, and/or regionalized care will be the leading systems tomorrow.
100. Patient safety remains a concern in critically ill patients, and a primary barrier to improving
patient safety is physicians’ inability to change their practice patterns.


GENERAL APPROACH TO THE
CRITICALLY ILL PATIENT
Manuel Pardo, Jr., MD, and Michael A. Gropper, MD, PhD

CHAPTER 1

I. BASIC LIFE SUPPORT

This book deals with many different aspects of critical care. Each disorder has specific diagnostic

and management issues. However, when initially evaluating a patient, one must have a
conceptual framework for the patterns of organ system dysfunction that are common to many
types of critical illness. Furthermore, in the patient with multiple organ failure, resuscitation or
stabilization is often more important than establishing an immediate, specific diagnosis.
1. Which organ systems are most commonly dysfunctional in critically ill patients?
The respiratory system, the cardiovascular system, the internal or metabolic environment, the
central nervous system (CNS), and the gastrointestinal tract.
2. What system should be evaluated first?
The first few minutes of evaluation should address life-threatening physiologic abnormalities,
usually involving the airway, the respiratory system, and the cardiovascular system. The
evaluation should then expand to include all organ systems.
3. Which should be performed first—diagnostic maneuvers or therapeutic
maneuvers?
The management of a critically ill patient differs from the typical sequence of history and physical
examination followed by diagnostic tests and therapeutic plans. The pace of assessment and
therapy is quicker, and simultaneous evaluation and treatment are necessary to prevent
further physiologic deterioration. For example, if a patient has a tension pneumothorax, the
immediate placement of a chest tube may be lifesaving. Extra time should not be taken to
transport the patient to a monitored setting. If there are no obvious life-threatening abnormalities,
it may be appropriate to transfer the patient to the intensive care unit (ICU) for further
evaluation. Many patients are admitted to the ICU solely for continuous electrocardiogram
monitoring and more frequent nursing care.
4. How do you evaluate the respiratory system?
The most important function of the lungs is to facilitate oxygenation and ventilation. Physical
examination may reveal evidence of airway obstruction or respiratory failure. These signs include
cyanosis, tachypnea, apnea, accessory muscle use, gasping respirations, and paradoxic
respirations. Auscultation may reveal rales, rhonchi, wheezing, or asymmetric breath sounds.
5. Define paradoxic respirations and accessory muscle use. What is their
significance?
Normal breathing involves simultaneous rise and fall of the abdomen and chest wall.

n A patient with paradoxic respirations has asynchrony of abdominal and chest wall
movement. With inspiration, the chest wall rises as the abdomen falls. The opposite occurs
with exhalation.
n Accessory muscle use refers to the contraction of the sternocleidomastoid and scalene
muscles with inspiration. These patients have increased work of breathing, which is the

9


10 CHAPTER 1 GENERAL APPROACH TO THE CRITICALLY ILL PATIENT
amount of energy the body consumes for the work of the respiratory muscles. Most patients
use accessory muscles before they have development of paradoxic respirations. Without
support from a mechanical ventilator, patients with paradoxic respirations or increased work of
breathing will eventually have respiratory muscle fatigue, hypoxemia, and hypoventilation.
6. What supplemental tests are useful in evaluating the respiratory system?
Although all tests should be individualized to the particular clinical situation, arterial blood
gas (ABG) analysis, pulse oximetry, and chest radiography rapidly provide useful information at a
relatively low cost-benefit ratio.
7. What therapy should be considered immediately in a patient with obvious
respiratory failure?
Mechanical ventilation may be an immediate life-sustaining therapy in a patient with obvious or
impending respiratory failure. Mechanical ventilation can be carried out invasively or
noninvasively. Invasive ventilation is carried out via endotracheal intubation or
tracheotomy. Noninvasive ventilation is instituted with a nasal mask or a full face mask. Even if
the patient does not have obvious respiratory distress, supplemental oxygen should be
administered until the oxygen saturation is measured. The risk of development of oxygeninduced hypercarbia is rare in any patient, including those with an acute exacerbation of chronic
obstructive pulmonary disease.
8. How do you evaluate the cardiovascular system?
The most important function of the cardiovascular system is the delivery of oxygen to the body’s
vital organs. The determinants of oxygen delivery are cardiac output and arterial blood oxygen

content. The blood oxygen content, in turn, is determined primarily by the hemoglobin
concentration and the oxygen saturation. It is difficult to determine the hemoglobin
concentration and the oxygen saturation by physical examination alone. Therefore the initial
evaluation of the cardiovascular system focuses on evidence of vital organ perfusion. New
technology may allow rapid assessment of hemoglobin with use of a noninvasive
spectrophotometric sensor.
9. How is vital organ perfusion assessed?
The measurement of heart rate and blood pressure is the first step. If the systolic blood pressure
is below 80 mm Hg or the mean blood pressure is below 50 mm Hg, the chances of inadequate
vital organ perfusion are greater. However, because blood pressure is determined by cardiac
output and peripheral vascular resistance, it is not possible to estimate cardiac output from blood
pressure alone. The vital organs and their method of initial evaluation are as follows:
n Lungs (see Questions 4-7)
n Skin: Assess warmth and capillary refill in all extremities.
n CNS: Assess level of consciousness and orientation.
n Heart: Measure blood pressure and heart rate, and ask for symptoms of myocardial ischemia
(e.g., chest pain).
n Kidneys: Measure urine output and creatinine level.
10. What supplemental tests are useful in the initial evaluation of the
cardiovascular system?
Electrocardiography is a potentially useful diagnostic test with a low cost-benefit ratio.
Cardiac enzyme tests, such as troponin measurement, are generally available within hours and
can suggest myocardial injury. Other tests, which may entail more risk and cost, should be
determined after the initial evaluation. These may include echocardiography, right-sided heart
catheterization, central venous pressure measurement, or coronary angiography.


CHAPTER 1 GENERAL APPROACH TO THE CRITICALLY ILL PATIENT 11
11. What therapies should be considered immediately in a patient with hypotension
and evidence of inadequate vital organ function?

Fluid and vasopressor therapy can rapidly restore vital organ perfusion, depending on the cause of the
deterioration. In most patients, a fluid challenge is well tolerated, although it is possible to precipitate
heart failure and pulmonary edema in a volume-overloaded patient. Other therapies that may be
immediately lifesaving include thrombolysis or coronary angioplasty for an acute myocardial
infarction. Patients with hypotension from sepsis may benefit from early therapy involving defined
goals for blood pressure, central venous pressure, central venous oxygen saturation, and hematocrit.
12. How do you evaluate the metabolic environment?
The clinical laboratory is required for most metabolic tests. It is difficult to evaluate the metabolic
environment by physical examination alone.
13. Why are metabolic changes important to detect in a critically ill patient?
Metabolic abnormalities such as acid-base, fluid, and electrolyte disturbances are common in
critical illness. These disorders may compound the underlying illness and require specific
treatment themselves. They may also reflect the severity of the underlying disease. Metabolic
disorders such as hyperkalemia and hypoglycemia can be life threatening. Prompt testing and
treatment may reduce morbidity and improve patient outcome.
14. Which laboratory tests should be performed in the initial evaluation of the
metabolic environment?
The selected tests should have a rapid reporting time, be widely available, and be likely to produce
a change in management. Tests that fit these criteria include measurements of glucose, white
blood cell count, hemoglobin, hematocrit, electrolytes, anion gap, blood urea nitrogen,
creatinine, and pH. Elevated lactate levels suggest tissue hypoperfusion, and normal lactate
clearance is suggestive of adequate fluid resuscitation. Some of these tests may be unnecessary
in a particular patient, and supplemental testing may be useful in others.
15. How do you evaluate the CNS?
A neurologic examination is the first step in evaluating the CNS. The examination should include
assessment of mental status (i.e., level of consciousness, orientation, attention, and higher
cortical function). CNS disturbances in critical illness can be subtle. Common changes include
fluctuations in mental status, changes in the sleep-wake cycle, or abnormal behavior. The
remainder of the neurologic examination includes assessment of respiratory pattern, cranial
nerves, sensation, motor function, and reflexes. Delirium, which is common in ICU patients, can

be evaluated with the confusion assessment method (CAM-ICU).
16. What diagnostic tests and therapies should be immediately considered in a
patient with altered mental status?
Oxygen therapy may be useful in patients with altered mental status from hypoxemia. Pulse
oximetry or ABG analysis should be done to evaluate this. Intravenous dextrose may be lifesaving
in patients with hypoglycemia. Additional diagnostic tests may be indicated depending on the
clinical situation. Lumbar puncture, head computed tomographic (CT) or magnetic resonance
imaging scan, electroencephalography, and metabolic testing may be useful in directing specific
therapies. Patients with acute ischemic stroke may benefit from tissue plasminogen activator
therapy, which is most effective when administered within 90 minutes of symptom onset.
17. How do you evaluate the gastrointestinal tract?
History and abdominal and rectal examination are the first steps in an initial evaluation of the
gastrointestinal tract. Abdominal catastrophes such as bowel obstruction and bowel
perforation are common inciting events leading to multiple organ failure. In addition, abdominal
distention can reduce the compliance of the respiratory system, leading to progressive
atelectasis and hypoxemia. Further diagnostic tests such as chest radiography, abdominal