Evidence-Based Emergency Medicine E-Book

Brian Rowe

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Serie: Evidence-Based Medicine
• Sprache: Englisch

Seitenzahl: 2176

Veröffentlichungsjahr: 2011

Beschreibung

Emergency physicians assess and manage a wide variety of problems from patients presenting with a diversity of severities, ranging from mild to severe and life-threatening. They are expected to maintain their competency and expertise in areas where there is rapid knowledge change. Evidence-based Emergency Medicine is the first book of its kind in emergency medicine to tackle the problems practicing physicians encounter in the emergency setting using an evidence-based approach. It summarizes the published evidence available for the diagnosis and treatment of common emergency health care problems in adults. Each chapter contextualizes a topic area using a clinical vignette and generates a series of key clinically important diagnostic and treatment questions. By completing detailed reviews of diagnostic and treatment research, using evidence from systematic reviews, RCTs, and prospective observational studies, the authors provide conclusions and practical recommendations. Focusing primarily on diagnosis in areas where evidence for treatment is well accepted (e.g. DVTs), and treatment in other diseases where diagnosis is not complex (e.g. asthma), this text is written by leading emergency physicians at the forefront of evidence-based medicine. Evidence-based Emergency Medicine is ideal for emergency physicians and trainees, emergency department staff, and family physicians specialising in the acute care of medical and injured patients.

Leseprobe

Contents

List of Contributors,

Foreword,

Acknowledgments,

List of Abbreviations,

Part 1 General Issues

1 Introduction

Brian H. Rowe & Peter C. Wyer

Case scenario

Introduction

Why EBEM?

Levels of evidence

Levels of evidence and systematic reviews

The Cochrane Collaboration

The Cochrane Library and emergency medicine

Question development

Locating the evidence: literature searching

Clinical epidemiology terminology

Collecting and interpreting the evidence for clinical practice

Conclusions

Acknowledgments

Conflicts of interest

References

2 Knowledge Translation: A Primer for Emergency Physicians

Eddy S. Lang, Peter C. Wyer & Marc Afilalo

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Conflicts of interest

References

3 Critical Appraisal: General Issues in Emergency Medicine

Suneel Upadhye

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature:

Conclusions

Acknowledgments

Conflicts of interest

References

4 Continuing Education

Joel Lexchin

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Conflicts of interest

References

5 Quality Improvement

Andrew Worster & Ann McKibbon

Clinical scenario

Background

General search strategy

Clinical questions

Critical review of the literature

Conclusions

Acknowledgments

References

6 Medication Adherence

Ursula Whalen & Sunil Kripalani

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Conflicts of interest

References

7 Emergency Department Triage

Sandy L. Dong & Michael Bullard

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Acknowledgments

Conflicts of interest

References

8 Emergency Department Overcrowding

Michael Schull & Matthew Cooke

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Conflicts of interest

References

Part 2 Respiratory

9 Emergency Management of Asthma Exacerbations

Brian H. Rowe & Carlos A. Camargo, Jr.

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Acknowledgments

Conflicts of interest

References

10 Chronic Obstructive Pulmonary Disease Exacerbations

Brian H. Rowe & Rita K. Cydulka

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Conflicts of interest

References

11 Diagnosis and Treatment of Community-Acquired Pneumonia

Sam G. Campbell & Tom Marrie

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Conflicts of interest

References

12 Deep Vein Thrombosis

Eddy S. Lang & Phil Wells

Case scenario

Background

General search strategy

Clinical questions

Conclusions

Acknowledgments

References

13 Pulmonary Embolism

Phil Wells & Michael Brown

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Acknowledgments

References

14 Prevention and Treatment of Influenza

Stephen R. Pitts

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

References

15 Anaphylaxis

Theodore Gaeta

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Acknowledgments

Conflicts of interest

References

Part 3 Cardiology

16 Chest Pain

Alain Vadeboncoeur, Jerrald Dankoff & Eddy S. Lang

Case scenario

Background

Clinical questions

General search strategy

Critical appraisal of the literature

Conclusions

References

17 Acute Coronary Syndromes,

Kirk Magee

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Acknowledgments

Conflicts of interest

References

18 Acute Myocardial Infarction

Bjug Borgundvaag

Case scenario

Background

Clinical questions

General search strategy

Critical appraisal of the literature

Conclusions

References

19 Acute Decompensated Heart Failure

Brett Jones & Sean P. Collins

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

References

20 Atrial Fibrillation,

Barry Diner

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Acknowledgments

Conflicts of interest

References

21 Ventricular and Supraventricular Arrhythmias

Eddy S. Lang & Eli Segal

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Acknowledgments

References

22 Cardiac Arrest

Riyad B. Abu-Laban & Michael Shuster

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Reference

Part 4 General Medical Conditions, 235

23 Severe Sepsis and Septic Shock

Peter W. Greenwald, Scott Weingart & H. Bryant Nguyen

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Acknowledgments

References

24 Delirium

Denise Nassisi & Andy Jagoda

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

References

25 Caring for the Elderly

Christopher R. Carpenter, Michael Stern & Arthur B. Sanders

Case scenario

Background

Clinical questions

General search strategy

Critical appraisal of the literature

Conclusions

Acknowledgments

Conflicts of interest

References

26 Syncope

Richard Lappin & James Quinn

Clinical scenario

Background

Clinical questions

General search strategy

Conclusions

Acknowledgments

Conflicts of interest

References

27 General Toxicology

Luke Yip, Nicole Bouchard & Marco L.A. Sivilotti

SCENARIO 1

Clinical scenario

Background

Clinical questions

General search strategy

Conclusions

SCENARIO 2

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

SCENARIO 3

Clinical scenario

Background

General search strategy

Clinical question

Critical review of the literature

Conclusions

Acknowledgments

Conflicts of interest

References

28 Toxicology: Acetaminophen and Salicylate Poisoning

Mark Yarema & Richard Dart

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature: acetaminophen

Critical review of the literature: salicylate

Conclusions

Conflicts of interest

References

Part 5 Injury,

29 Mild Traumatic Brain Injury

Jeffrey J. Bazarian & Will Townend

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Conflicts of interest

References

30 Neck Injuries

Marcia L. Edmonds & Robert Brison

Clinical scenario

Background

Clinical questions

General search strategy

Conclusions

Acknowledgments

References

31 Ankle Injuries

Jerome Fan

Clinical scenario

Background

Clinical questions

Critical review of the literature

Conclusions

Acknowledgments

Conflicts of interests

References

32 Knee Injuries

Anita Pozgay & Elisabeth Hobden

Case scenario

Background

Clinical questions

General search strategy

Conclusions

References

33 Wrist injuries

Sandy L. Dong & Brian H. Rowe

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Acknowledgments

Conflicts of interest

References

34 Shoulder Injuries

Jenn Carpenter, Marcel Emond & Robert Brison

Clinical scenarios

Background

Clinical questions

General search strategy

Critical appraisal of the literature

Conclusions

Conflicts of interest

References

35 Chest Trauma

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

References

36 Hemorrhagic Shock

Dennis Djogovic, Jonathan Davidow & Peter Brindley

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

References

Part 6 Genitourinary and Abdominal,

37 Acute Appendicitis

James A. Nelson & Stephen R. Hayden

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

References

38 Ectopic Pregnancy

Heather Murray & Elisha David Targonsky

Clinical scenario

Background

Clinical questions

General search strategy

Critical appraisal of the literature

Conclusions

Acknowledgement

References

39 Acute Ureteric Colic

Andrew Worster

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Acknowledgments

Conflicts of interest

References

40 Urinary Tract Infection

Rawle A. Seupaul, Chris McDowell & Robert Bassett

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Conflicts of interest

References

41 Pelvic Inflammatory Disease

Linda Papa & Kurt Weber

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

References

42 Pregnancy

Ashley Shreves

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Conflicts of interest

References

43 Gastrointestinal Bleeding

Michael Bullard & Justin Cheung

Clinical scenario

Background

Clinical questions

General search strategy

Clinical review of the literature

Conclusions

Acknowledgments

References

Part 7 Neurosciences

44 Transient Ischemic Attack

Ted Glynn

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

References

45 Stroke

William J. Meurer & Robert Silbergleit

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Conflicts of interest

References

46 Subarachnoid Hemorrhage

Jeffrey J. Perry

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Acknowledgments

Conflicts of interest

References

47 Bacterial Meningitis

Cheryl K. Chang & Peter C. Wyer

Case scenario

Background

Clinical questions

General search strategy

Critical appraisal of the literature

Conclusions

References

48 Migraine and Other Primary Headache Disorders

Benjamin W. Friedman

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

References

49 Seizures

Elizabeth B. Jones

Clinical scenario

Background

Clinical questions

General search strategy

Conclusions

Conflicts of interest

References

50 The Agitated Patient

Michael S. Radeos & Edwin D. Boudreaux

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Conflicts of interest

References

Part 8 ENT

51 Sore Throat

Benson Yeh & Barnet Eskin

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Acknowledgments

Conflicts of interest

References

52 Rhinosinusitis

Errol Stern

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

References

53 Conjunctivitis

Nicola E. Schiebel

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

References

Part 9 Minor Procedures

54 Procedural Sedation and Analgesia

David W. Messenger & Marco L. A. Sivilotti

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

References

55 Wound Repair

Helen Ouyang & James Quinn,

Case scenario

Background

Clinical questions

General search strategy

Critical review of the literature:

Conclusions

Conflicts of interest

References

56 Soft Tissue Abscess,

Heather Murray

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Conflicts of interest

References

57 Ultrasound Use: Three Select Applications

Srikar Adhikari & Michael Blaivas

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

References

Part 10 Public Health

58 Injury Prevention

Mary Patricia McKay & Liesl A. Curtis

Clinical scenarios

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Conflicts of interest

References

59 Intimate Partner Violence

Debra Houry

Clinical scenario

Background

Clinical questions

General search strategy

Conclusions

Conflicts of interest

References

60 Smoking Cessation

Lisa Cabral & Steven L. Bernstein

Clinical scenario

Background

Clinical questions

General search strategy

Conclusions

Conflicts of interest

References

61 Immunization

Jeremy Hess & Katherine L. Heilpern

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Acknowledgments

Conflicts of interest

References

62 Alcohol and Other Drugs

Barbara M. Kirrane, Linda C. Degutis & Gail D’Onofrio

SCENARIO 1

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

SCENARIO 2

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Conflicts of interest

References

63 Elder Abuse

Ralph J. Riviello

Clinical scenario

Background

Clinical questions

General search strategy

Critical review of the literature

Conclusions

Conflicts of interest

References

Index

This book is dedicated to:

Our patients, who have generated the clinical questions proposed in this book and who deserve our best efforts to identify, synthesize, update and disseminate evidence-based care;

The many practitioners from within and outside emergency medicine who have helped advance the field of evidence-based emergency medicine over the past two decades;

And finally to our families, especially our spouses/partners, for their support and encouragement throughout our careers and during the production of this book.

This edition first published 2009, ©2009 by Blackwell Publishing Ltd

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Library of Congress Cataloguing-in-Publication Data

Evidence-based emergency medicine / edited by Brian H. Rowe.

p.; cm.

Includes bibliographical references.

ISBN 978-1-4051-6143-5

1. Emergency medicine. 2. Evidence-based medicine. I. Rowe, Brian H.

[DNLM: 1. Emergency Medicine-methods. 2. Evidence-Based Medicine-methods. WB 105 E935 2008]

RC86.7.E95 2008

616.02'5-dc22 2008010823

ISBN: 9781405161435

List of contributors

Riyad B. Abu-Laban MD, MHSc, FRCPCAssistant Professor Division of Emergency MedicineUniversity of British Columbia Vancouver, British Columbia, Canada andAttending Physician and Research Director Department of Emergency MedicineVancouver General Hospital Vancouver, British Columbia, Canada

Srikar Adhikari MD, RDMSAssistant ProfessorDepartment of Emergency MedicineUniversity of NebraskaOmaha, Nebraska, USA

Marc AfilaloAssociate ProfessorDepartment of Family Medicine McGill University Montreal, Quebec and Chief of Emergency Medicine Department of Emergency MedicineSMBD Jewish General Hospital Montreal, Quebec, Canada

Robert Bassett DODepartment of Emergency MedicineIndiana University School of MedicineIndianapolis, Indiana, USA

Jeffrey J. Bazarian MD, MPHAssociate ProfessorDepartments of Emergency Medicineand NeurologyUniversity of Rochester School of Medicine andDentistryRochester, New York, USA

Steven L. Bernstein MDVice Chair for ResearchAssociate Professor of Clinical EmergencyMedicineFamily/Social Medicine, Epidemiology/ Population Health Albert Einstein College of MedicineMontefiore Medical Center Department of Emergency Medicine Bronx, New York, USA

Michael Blaivas MD, RDMSAssistant Professor of Internal Medicine Department of Internal Medicine Northside Hospital Forsyth Cumming, Georgia, USA

Bjug Borgundvaag MD, PhDAssistant Professor Schwartz/Reisman Emergency Centre Mount Sinai Hospital Toronto, Ontario, Canada

Nicole Bouchard MDAssistant Clinical Professor Emergency Medicine Department New York–Presbyterian Hospital Columbia University Medical Center New Yorkand Director of Medical Toxicology New York City Poison Control Center New York, USA

Edwin D. Boudreaux PhDResearch DirectorDepartment of Emergency Medicine Cooper University Hospital Camden, New Jersey, USA

Peter Brindley MDStaff PhysicianDivision of Critical Care Medicine University of Alberta Hospital Edmonton, Alberta, Canada

Robert Brison, MD, MPH, MSc, FRCPCProfessorDepartments of Emergency Medicineand Community Health and EpidemiologyQueen’s UniversityKingston, Ontario, Canada

Michael Brown MD, MScProfessor of Epidemiology and EmergencyMedicineCollege of Human MedicineMichigan State UniversitySpectrum Health-Butterworth HospitalsGrand Rapids, Michigan, USA

Michael Bullard MD, CCFP(EM), ABEM,FRCPCProfessorDepartment of Emergency Medicine University of Alberta Edmonton, Alberta, Canada

Lisa Cabral MDAssistant Professor of Clinical EmergencyMedicineAlbert Einstein College of MedicineMontefiore Medical CenterDepartment of Emergency MedicineBronx, New York, USA

Carlos A. Camargo, Jr., MD, DrPHDirector, EMNet Coordinating Center Department of Emergency Medicine Massachusetts General Hospital Boston, Massachusetts, USA

Sam G. Campbell MB BCh, CCFP(EM),CHE, Dip PEC(SA)Associate ProfessorDepartment of Emergency MedicineDalhousie UniversityHalifax, Nova Scotia, Canada

Christopher R. Carpenter MD, MScAssistant ProfessorDivision of Emergency MedicineSt. Louis School of MedicineWashington UniversitySt. Louis, Missouri, USA

Jenn Carpenter MD, FRCPCAssistant ProfessorDepartments of Emergency Medicineand Community Health and EpidemiologyQueen’s UniversityKingston, Ontario, Canada

Cheryl K. Chang MD, MPHAssistant Clinical ProfessorDepartment of MedicineColumbia University College of Physicians andSurgeonsNew York, USA

Justin Cheung MD, FRCPStaff Physician Division of Gastroenterology Department of Medicine University of Alberta Edmonton, Alberta, Canada

Sean P. Collins MD, MScAssistant Professor Department of Emergency Medicine University of Cincinnati Cincinnati, Ohio, USA

Matthew Cooke PhD, FCEM, FRCS(Ed)Professor of Emergency MedicineWarwick Medical SchoolUniversity of Warwick, Coventryand Heart of England NHS Foundation TrustBirmingham, UK

Liesl A. Curtis MDEmergency Medicine Physician Department of Emergency Medicine Georgetown University Washington, District of Columbia, USA

Rita K. Cydulka MD, MSAssociate Professor and Vice ChairDepartment of Emergency MedicineMetroHealth Medical CenterCase Western Reserve University School ofMedicineCleveland, Ohio, USA

Jerrald DankoffAssistant ProfessorDepartment of Emergency MedicineMcGill UniversityMontreal, Quebecand Attending StaffDepartment of Emergency Medicine SMBD Jewish General Hospital Montreal, Quebec, Canada

Richard Dart MD, PhDDirectorRocky Mountain Poison and Drug CenterDenver, Colorado, USA

Jonathan Davidow MDStaff PhysicianDepartment of Emergency MedicineUniversity of AlbertaEdmonton, Albertaand Division of Critical Care MedicineUniversity of Alberta HospitalEdmonton, Alberta, Canada

Linda C. Degutis, DrPHAssociate ProfessorSection of Emergency MedicineYale UniversityNew Haven, Connecticut, USA

Barry Diner MD, MPH, FACEPAssistant ProfessorDepartment of Emergency MedicineEmory University School of MedicineEmory UniversityAtlanta, Georgia, USA

Dennis Djogovic MD, FRCPCAssistant Clinical ProfessorDepartment of Emergency MedicineUniversity of AlbertaEdmonton, Albertaand Division of Critical Care MedicineUniversity of Alberta HospitalEdmonton, Alberta, Canada

Sandy L. Dong MD, MSc, FRCPC, DABEMAssistant Clinical Professor and RCPS AssistantProgram DirectorDepartment of Emergency MedicineUniversity of AlbertaEdmonton, Alberta, Canada

Gail D’Onofrio MD, MSProfessor and ChairSection of Emergency MedicineYale UniversityNew Haven, Connecticut, USA

Marcia L. Edmonds MD, MScStaff PhysicianDivision of Emergency Medicine University of Western Ontario London, Ontario, Canada

Marcel Emond MD, MSc, FRCPCProfessorDepartments of Emergency Medicineand Family MedicineLaval UniversityQuebec, Canada

Barnet Eskin MD PhDAssistant Research Director Department of Emergency Medicine Morristown Memorial Hospital Morristown, New Jersey, USA

Jerome Fan MD, FRCPStaff PhysicianDepartment of Emergency MedicineMcMaster UniversityHamilton, Ontario, Canada

Benjamin W. Friedman MD, MSAssistant Professor Department of Emergency Medicine Albert Einstein College of Medicine Montefiore Medical Center Bronx, New York, USA

Theodore Gaeta DO, MPHVice-Chairman & Residency DirectorDepartment of Emergency MedicinebrNew York Methodist HospitalBrooklyn, New York, USA andAssociate Professor of Emergency in ClinicalMedicineWeill Medical College of Cornell UniversityNew York, USA

Ted Glynn MD, FACEPProgram DirectorMichigan State University, Emergency MedicineResidency, LansingandAssistant Clinical Professor of EmergencyMedicineColleges of Human and Osteopathic MedicineMichigan State UniversityEast LansingandAttending PhysicianIngham Regional Medical CenterLansing, Michigan, USA

Peter W. Greenwald MDVisiting Assistant Professor of MedicineDivision of Emergency MedicineNew York–Presbyterian HospitalWeill Medical College of Cornell UniversityNew York, USA

Stephen R. Hayden MDResidency Director Department of Emergency Medicine University of California at San Diego San Diego, California, USA

Katherine L. Heilpern MDResidency DirectorAda Lee and Pete Correll Professor and ChairDepartment of Emergency MedicineEmory University School of MedicineEmory UniversityAtlanta, Georgia, USA

Jeremy Hess MD, MPHAssistant ProfessorDepartments of Emergency Medicineand Environmental and Occupational HealthEmory University Schools of Medicine and PublicHealthEmory UniversityAtlanta, Georgia, USA

Elisabeth Hobden MD, FRCPC, DipSport MedDepartment of Emergency Medicine The Ottawa Hospital Ottawa, Ontario, Canada

Debra Houry MD, MPHDirector, Center for Injury Control Vice Chair for Research Department of Emergency Medicine, Emory University Atlanta, Georgia, USA

Andy Jagoda MDProfessorDepartment of Emergency Medicine Mount Sinai School of Medicine New York, USA

Brett Jones MD, PhDStaff PhysicianYa vapai Medical CenterPrescott, AZ, USA

Elizabeth B. Jones MD, FACEPAssistant Professor Department of Emergency Medicine University of Texas Health Science Center Houston, Texas, USA

Barbara M. Kirrane MDAssistant ProfessorSection of Emergency MedicineYale UniversityNew Haven, Connecticut, USA

Sunil Kripalani MD, MScAssistant ProfessorDivision of General Internal Medicine and PublicHealthVanderbilt UniversityNashville, Tennessee, USA

Eddy S. Lang MDCM, CCFP(EM), CSPQAssistant Professor of Emergency Medicine Department of Family Medicine McGill University Montreal, Quebecand Attending Physician Department of Emergency Medicine SMBD Jewish General Hospital Montreal, Quebec, Canada

Richard Lappin MD, PhDAssistant Professor of Clinical Medicineand Assistant Attending Physician Department of Emergency Medicine New York–Presbyterian Hospital Weill Cornell Medical Center New York, USA

Joel Lexchin MDProfessor, School of Health Policy andManagementYork UniversityToronto, Ontarioand Associate ProfessorDepartment of Family and Community MedicineUniversity of Toronto, Torontoand Attending StaffEmergency DepartmentUniversity Health NetworkToronto, Canada

Kirk Magee MD, MSc, FRCP(C)Associate Professor and RCPS Program DirectorDepartment of Emergency MedicineDalhousie UniversityHalifax, Nova Scotiaand QEII Health Sciences CentreHalifax InfirmaryHalifax, Nova Scotia, Canada

Tom Marrie MD, FRCPCProfessor and Dean Faculty of Medicine and Dentistry University of Alberta Edmonton, Alberta, Canada

Chris McDowell MDDepartment of Emergency Medicine Indiana University School of Medicine Indianapolis, Indiana, USA

Mary Patricia McKay, MD, MPHAssociate Professor Department of Emergency Medicine George Washington University Washington, District of Columbia, USA

Ann McKibbon PhDAssociate ProfessorDepartment of Clinical Epidemiology andBiostatisticsMcMaster University Hamilton, Ontario, Canada

David W. Messenger MDAssistant ProfessorDepartment of Emergency MedicineQueen’s UniversityKingston, Ontario, Canada

William J. Meurer MDLecturer in Emergency Medicine and Neurology Department of Emergency Medicine University of Michigan Ann Arbor, Michigan, USA

Heather Murray MD, MSc, FRCP(C)Assistant ProfessorDepartments of Emergency Medicineand Community Health and EpidemiologyQueen’s UniversityKingston, Ontario, Canada

Denise Nassisi MDAssistant Professor Department of Emergency Medicine Mount Sinai School of Medicine New York, USA

James A. Nelson MDAssistant Clinical Professor Department of Emergency Medicine University of California at San Diego San Diego, California, USA

David H. Newman, MDAssistant ProfessorDepartment of MedicineColumbia University College of Physiciansand Surgeons, New YorkandDirector of Clinical ResearchDepartment of Emergency MedicineSt. Luke’s/Roosevelt Hospital CenterNew York, USAAssociate ProfessorDepartments of Emergency Medicine andMedicineDivision of Pulmonary and Critical Care MedicineLoma Linda UniversityLoma Linda, California, USA

Helen Ouyang MD, MPHResident Physician in Emergency Medicine Department of Emergency Medicine Brigham and Women’s Hospital andMassachusetts General Hospital Boston, Massachusetts, USA

Linda Papa MD, MSc, CCFP, FRCP(C), FACEPDirector of Academic Clinical ResearchDepartment of Emergency MedicineOrlando Regional Medical CenterOrlando, Floridaand Adjunct ProfessorDepartment of Emergency MedicineCollege of Medicine, University of FloridaGainsville, Floridaand Clinical Associate ProfessorFlorida State University College of MedicineTallahassee, Florida, USA

Jeffrey J. Perry MD, MSc, CCFP-EMAssistant ProfessorDepartment of Emergency MedicineUniversity of OttawaOttawa, Ontario, Canada

Stephen R. PittsAssociate Professor Department of Emergency Medicine Emory University School of Medicine Emory Crawford Long Hospital Atlanta, Georgia, USA

Anita Pozgay MD, FRCPC, Dip Sports

MedAssistant ProfessorDepartment of Emergency MedicineThe Ottawa HospitalOttawa, Ontario, Canada

James Quinn MD, MSAssociate Professor of Surgery/EmergencyMedicineDivision of Emergency MedicineStanford UniversityStanford, California, USA

Michael S. Radeos MDResearch DirectorDepartment of Emergency Medicine New York Hospital Queens Flushing, New York, USA

Ralph J. Riviello MD, MS, FACEP,FAAEMAssociate Professor Director of Clinical Researchand Associate Program Director Department of Emergency Medicine Thomas Jefferson University Philadelphia, Pennsylvania, USA

Brian H. Rowe MD, MSc, CCFP(EM), FCCPProfessor and Research Director Department of Emergency Medicine University of Alberta Edmonton, Alberta, Canada

Arthur B. Sanders MDProfessorDepartment of Emergency Medicine University of Arizona College of Medicine Tucson, Arizona, USA

Nicola E. Schiebel MD, FRCPCAssistant ProfessorDepartment of Emergency MedicineMayo ClinicRochester, Minnesota, USA

Michael Schull MD, MSc, FRCPCSenior ScientistInstitute for Clinical Evaluative SciencesTorontoand DirectorDivision of Emergency MedicineDepartment of MedicineUniversity of TorontoToronto, Canada

Eli SegalStaff PhysicianDepartment of Family MedicineMcGill UniversityMontreal, Quebecand Department of Emergency MedicineSMBD Jewish General HospitalMontreal, Quebec, Canada

Rawle A. Seupaul MDAssociate Professor of Clinical EmergencyMedicineDepartment of Emergency MedicineIndiana University School of MedicineIndianapolis, Indiana, USA

Ashley Shreves MDAttending Physician Department of Emergency Medicine St. Luke’s–Roosevelt Hospital New York, USA

Michael Shuster MD, FRCPCStaff PhysicianDepartment of Emergency MedicineMineral Springs HospitalBanff, Alberta, Canada

Robert Silbergleit MDAssociate ProfessorDepartment of Emergency MedicineUniversity of MichiganAnn Arbor, Michigan, USA

Richard Sinert DOAssociate Professor and Research Director Department of Emergency Medicine Downstate Medical Center State University of New YorkBrooklyn, New York, USA

Marco L. A. Sivilotti MD, MSc, FRCPC,

FACEP, FACMTAssociate ProfessorDepartments of Emergency Medicineand Pharmacology and ToxicologyQueen’s UniversityKingston, Ontario andConsultantOntario Poison CentreToronto, Ontario, Canada

Errol Stern MDCM, FRCPC, FACEP, CSPQAssistant Professor Department of Family Medicine McGill University Montreal, Quebec andAttending Staff Emergency Medicine SMBD Jewish General Hospital Montreal, Quebec, Canada

Michael Stern MDAssistant Professor of Medicine Department of Medicine Division of Emergency Medicine Weill Cornell Medical Center New York, USA

Elisha David Targonsky BSc, MScDepartmental AssistantDepartment of Emergency Medicine andCommunity Health and EpidemiologyQueen’s UniversityKingston, Ontario, Canada

Will Townend MD, FCEMDepartment of Emergency MedicineHull Royal Infirmary Hull, UK

Suneel Upadhye MD, MSc, FRCPC, ABEMAssistant Clinical Professor Division of Emergency Medicine McMaster University Hamilton, Ontario, Canada

Alain Vadeboncoeur MD, CCFP, CSPQ(EM)Assistant Professor Department of Family Medicine University of Montreal Montreal, Quebecand Chief of Emergency Medicine Montreal Heart Institute Montreal, Quebec, Canada

Kurt Weber MDAttending PhysicianDepartment of Emergency MedicineOrlando Regional Medical CenterOrlando, Floridaand Clinical Assistant ProfessorFlorida State University College of MedicineTallahassee, Florida, USA

Scott Weingart MDDirectorDivision of Emergency Critical Care Department of Emergency Medicine Mount Sinai School of Medicine New York, USA

Phil Wells MD, MSc, FRCPCProfessor and Chief Division of Hematology Department of Medicine University of Ottawa Ottawa, Ontarioand Director of Clinical Research The Ottawa Hospital Ottawa, Ontario, Canada

Ursula Whalen MDDivision of General Internal Medicine and Public HealthVanderbilt University Nashville, Tennessee, USA

Andrew Worster MD, CCPF (EM), MSc,FCFPAssociate ProfessorEmergency MedicineClinical Epidemiology & BiostatisticsMcMaster UniversityHamilton, Ontario, Canada

Peter C. Wyer MDAssociate Clinical ProfessorDepartment of MedicineColumbia University College of Physicians andSurgeonsNew York, USA

Mark Yarema MD, FRCPCDivision Chief, Research Department of Emergency Medicine Calgary Health Region Calgary, Alberta, Canada

Benson Yeh MDResidency Director Department of Emergency Medicine Brooklyn Hospital Center Brooklyn, New York, USA

Luke Yip MD, FACMT, FACEM, FACEPConsultantDepartment of EmergencyThe Prince Charles HospitalChermside, Queensland, Australiaand Attending FacultyRocky Mountain Poison and Drug CenterDenver, Coloradoand Attending Staff PhysicianDepartment of MedicineDivision of Medical ToxicologyDenver Health Medical CenterDenver, Coloradoand Clinical Assistant ProfessorSchool of PharmacyUniversity of Colorado Health Sciences CenterDenver, Colorado, USA

Shahriar Zehtabchi MDAssociate ProfessorDepartment of Emergency MedicineDownstate Medical CenterState University of New YorkBrooklyn, New York, USA

Acknowledgments

The editors would like to acknowledge the publishers Wiley-Blackwell, and especially Ms. Mary Banks, for assisting in the early development of the Evidence-based Emergency Medicine idea. We would also like to express our sincerest appreciation to our development editor at Wiley-Blackwell, Ms. Laura Beaumont, for her guidance, patience and friendship during the production of this book. We wish her continued success in her future work. We would also like to thank the Evidence-based Emergency Medicine authors for their often Herculean efforts to produce the chapters that have contributed to the success of this book. We are indebted to Mirjana Misina for her careful guidance through production editing. Finally, as the editor, I would like to personally thank the section editors for their time, interest and dedication to the completion of this book.

Brian H. Rowe

List of Abbreviations

ABCairway, breathing and circulationACEangiotension-converting enzymeACEPAmerican College of Emergency PhysiciansAHRQAgency for Healthcare Research and QualityAPanteroposteriorARRabsolute risk reductionASAacetyl-salicylic acidBETbest evidence topic β2-agonistsbeta-2-receptor agonist agentsBMJBritish Medical JournalCADTHCanadian Agency for Drugs and Technologies in HealthCATScritically appraised topicsCDCCenters for Disease Control and PreventionCDSRCochrane Database of Systematic ReviewsCENTRALCochrane Central Register of Controlled TrialsCIconfidence intervalCINAHLCompedium of International Nursing and Allied Health LiteratureCMEcontinuing medical educationCOPDchronic obstructive pulmonary diseaseCPDcontinuing professional developmentCPGclinical practice guidelinesCPRclinical prediction ruleCTcomputerized tomographyCXRchest X-rayDAREDatabase of Abstracts of Reviews of EffectsDSMDiagnostic and Statistical Manual of MentalDisorders, 4th ednDVTdeep vein thrombosisEBEMevidence-based emergency medicineEBMevidence-based medicineECGelectrocardiogramEDemergency departmentELISAenzyme-linked immunoadsorbent assayEMBASEEuropean-based electronic database maintained by ElsevierEMSemergency medical servicesESeffect sizeFASTfocused assessment with sonography for traumaFDAUS Food and Drug AdministrationFEV1forced expiratory volume in one secondGCSGlasgow Coma ScoreHAHeadacheHIVhuman immunodeficiency virusHRhazard ratioICCintraclass correlation coefficientICDInternational Classification of DiseaseICUintensive care unitIMintramuscularINRinternational normalized ratioIQRinter-quartile rangeIVintravenousJAMAJournal of the American Medical AssociationKTknowledge translationLLMWlow molecular weightLOSlength of stayLRlikelihood ratioLWBSleft without being seenMDImetered dose inhalerMEDLINENational Library of Medicine electronic databaseMeSHmedical subject headingmgmilligramMgSO4magnesium sulfateMImyocardial infarctionmlmillilitersMMSEMini Mental Status ExaminationMRImagnetic resonance imagingMRSAmethicillin-resistant Staphylococcus aureusNHSUK National Health ServiceNICENational Institute for Health and ClinicalExcellenceNNHnumber needed to harmNNTnumber needed to treatNSAIDnon-steroidal anti-inflammatory drugO2oxygenORodds ratio/sPBLproblem-based learningPDSAplan, do, study and actPEpulmonary embolismPEFpeak expiratory flowPICOpopulation, intervention, control and outcomePICO-Dpopulation, intervention, control, outcome and designPOper oralQIquality improvementRCAroot cause analysisRCERational Clinical Examination Series of JAMARCTrandomized controlled trialROCreceiver operating curveRRrelative risk/sRRRrelative risk reductionSaO2oxygen saturationSARSsevere acute respiratory syndromeSCsubcutaneousSDstandard deviationSMDstandardized mean differenceSRsystematic reviewSTEMIST segment elevation myocardial infarctionSVCsuperior vena cavaTBITraumatic brain inTIAtransient ischemic attackt-PAtissue plasminogen activatorVTEvenous thromboembolismWBCwhite blood cellWHOWorld Health OrganizationWMDweighted mean difference

1 General Issues

1 Introduction

Brian H. Rowe1 & Peter C. Wyer2

1Department of Emergency Medicine, University of Alberta, Edmonton,Canada

2Department of Medicine, Columbia University College of Physicians and Surgeons, New York, USA

Case scenario

A 25-year-old woman presented to an emergency department(ED) with an exacerbation of her migraine headaches. Her migraine headaches had previously been well controlled; however, stressful conflicts had recently occurred at work, she had not been able to sleep properly for two nights and she admitted unusually low fluid intake for the previous 2 days. She reported that her headache developed gradually, was associated with nausea and vomiting, and she rated the headache as 9 on a 10-point headache pain scale. She denied fever, syncope or other signs of pathological headaches, and assessed the episode as being “similar to my last migraine headache that brought me to the emergency department 2 years ago”.

She improved quickly with intravenous saline and metoclopramide and was ready for discharge home after 90 minutes. Her headache at reassessment was 1 out of 10 and her nausea had resolved. The patient informed you that she was late for an important work meeting that would consume her time for the next 2 days and wondered what she could do to minimize the risk of suffering a recurrence.

Introduction

What is evidence-based emergency medicine (EBEM) and why is there such a controversy over the concept and contempt for the phrase? The term evidence-based medicine (EBM) was first coined in the early 1990s by Gordon Guyatt [1] and has now become a stable in the medical lexicon. In addition to EBM’s long history, controversy exists regarding its components and value in decision making [2,3]. In most cases, however, it can be described as the combined use of experience, best evidence and patient’s preference and values to develop an approach to a clinical problem, often referred to as evidence-based medical care.

The migraine headache example may help readers better understand the concept. The patient’s question related to prevention of headache and this topic is well covered in the chapter on migraine headaches in this book (See chapter 48). From an evidence perspective, the well-informed clinician knows that there is evidence that a dose of dexamethasone in the emergency department (ED) (best evidence based on a systematic review (SR) of randomized controlled trials (RCTs)) is helpful [4]. Moreover, experience reminds the clinician that patients with moderate to severe migraine headaches also can deteriorate, re-present to the ED, and/or lose valuable time from work and other activities (clinical experience). The clinician is concerned and wishes to protect the patient from any and all of these events (and so does her employer). Unfortunately, the patient protests this decision because corticos-teroids cause her to develop acne, retain water and have insomnia. She also has a major weekend function and feels these medications may create havoc with her social life. Despite the clinician’s reassurances, she refuses the intravenous corticosteroid treatment (patient preference and values). Readers in clinical practice will be very familiar with this type of scenario.

What is the evidence-based decision in this case? Some traditionalists may suggest that their decision is final and the patient should accept the corticosteroid treatment. The EBM clinician might further use the available evidence to explain the benefits and risks of treatment options, in conjunction with the patient’s preference and his/her experience. In the event that agreement cannot be reached between the clinician and the patient, the EBEM approach would propose an alternative “next-best evidence” and similarly reasonable approach. For example, the clinician may recognize that reduction of pain to less than two out of ten reduces headache relapse [5]. Moreover, the addition of education about triggers and very close follow-up may improve outcomes in such patients. It is this combination of evidence, patient preference and clinical experience that coalesces to form the EBEM decision.

Why EBEM?

The EBM approach may seem intuitive to many emergency practitioners. However, when originally proposed, debate ensued, and in some cases continues [6,7]. This forces the question: why is this being proposed in emergency medicine? In a therapy issue, clinicians must ultimately decide whether the benefits of treatment are worth the costs, inconvenience, and harms associated with the care. This is often a difficult task; however, it is made more difficult by the exponentially increasing volume of literature and the lack of time to search and distill this evidence [8]. Although clinicians of the early 21st century have an urgent need for just-in-time, on-demand clinical information, their time to access such information has likely never been as compressed. Increases in patient volume and complexity, patient care demands, and the lack of access to resources have exacerbated the work frustrations for many clinicians. These concerns often take precedence over seeking the most relevant, up-to-date and comprehensive evidence for patient problems.

Despite the fact that the most common problems posed by patients presenting to emergency rooms are encountered daily around the world, appropriate treatment approaches are often not fully employed and practice variation is impressive. For a variety of reasons, the results from high level evidence such as RCTs are not readily available to busy clinicians and keeping up to date is becoming increasingly difficult. Moreover, a valid, reliable and up-to-date clinical bottom line to guide treatment decisions has been elusive [8].

However, availability ofhigh quality published trialsand systematic reviews relevant to an area of practice are not the only components necessary to practicing “best evidence medicine”. Clinicians also need rigorously produced, synthesized best evidence information to assist them at the point of care. In emergency care, time is increasingly more precious and the need for this digestible information has never been greater.

Levels of evidence

A wide variety of tools to describe levels of evidence have been developed and employed in clinical medicine to reflect the degree of confidence to which results from research may be accepted as valid. From levels of evidence, strengths of recommendations are generated which are graded according to the strength of the scientific evidence supporting them. These levels of evidence can be criticized forbeingdifferent with eachsetofguidelines or report, being overly complex, and being almost universally focused on therapeutic interventions.

Recently, a group of experts in the field of guidelines introduced a grading system as part of an effort to develop a single approach supported by international consensus. The Grades of Recommendation, Assessment, Development and Evaluation (GRADE) Working Group have published their recommendations, which have been adopted by increasing numbers of specialty and health policy organizations [9]. The GRADE system classifies quality of evidence into one of four levels (high, moderate, low and very low) and quality of recommendations in one of two levels (strong and weak).

Once again, an example may be illustrative. In the case scenario described above dealing with therapy, the highest level of evidence (HIGH) is based on RCTs. A single RCT can retain HIGH grading if there are no study limitations, the threats to validity are low, the association is strong and adjustments for all potential confounders have been performed. Although HIGH status is awarded to RCTs, many trials in emergency medicine are not large enough to maintain this evidence status. The evidence would similarly retain its HIGH ranking if meta-analysis of two or more similar trials show consistency of effect and statistically significant relative risk (RR) results (> 2.0 or < 0.5 for reduction) [10]. Fortunately, in this case, the systematic review does support the single clinical trial identified (see Chapter 48).

While considerable debate exists regarding the relative merits of evidence derived from large individual trials versus systematic reviews [11], due to the costs associated with large, multi-centered trials, they remain uncommon across emergency medicine and remain restricted to certain topic areas (e.g., cardiology, rheumatology, stroke, and so forth). While examples of large databases and observational studies do exist in emergency medicine [12], smaller studies are much more common. Consequently, it is likely that systematic reviews will play an increasingly important role in the future decisions made by patients, clinicians, administrators and society in all areas of health care.

MODERATE evidence is based on RCTs that contain flaws that preclude a HIGH evidence rating or observational studies. The RCTs may show either positive trends that are not statistically significant or no trends and are associated with a high risk of false-negative results. The observational studies may be elevated to HIGH evidence (from LOW) in certain cases, such as when a statistically significant relative risk of > 5 (< 0.2) is identified based on direct evidence with no major threats to validity.

Finally, a LOW level of evidence is based on observational studies of any kind (e.g., cohorts, case series, case–control studies or cross-sectional studies). VERY LOW grading can be achieved when evidence is based on observational studies of low quality or the opinion of respected authorities or expert committees as indicated in published consensus conferences or guidelines.

In diagnostic studies, the same rules apply; however, most of the studies in this setting are not RCTs. Given the relatively recent development of the GRADE system, the editors of this text have not required authors to apply this in each chapter; although, given the summary of evidence provided in each chapter, readers should be able to rate the evidence presented using the general guide. Moreover, future editions of the book will focus on GRADE or similar systems of evidence assessment.

Levels of evidence and systematic reviews

As discussed above, one possible solution to the information dilemma for clinicians is to focus on evidence from systematic reviews (SRs) [13]. SRs address a focused clinical question, utilize comprehensive search strategies to avoid publication and selection biases, assess the quality of the evidence and, if appropriate, employ meta-analytic summary statistics to synthesize the results from research on a particular topic with a defined protocol. They represent an important and rapidly expanding body of literature for the clinician dealing with patients presenting to the emergency setting and they are an integral component of EBM.

Although there has been a recent increase in the production of diagnostic testing SRs, the most common application of SRs is in therapeutic interventions in clinical practice. One important exception is the Rational Clinical Examination (RCE) series published in the Journal of the American Medical Association (JAMA). This series presents SRs in the field of diagnostic testing (especially clinical examination and laboratory/imaging testing). Finally, the Cochrane Collaboration has developed a Diagnostic Methods Working Group and is planning to introduce diagnostic test systematic reviews to their collection of products in the near future. Unfortunately, the methodology of diagnostic SRs lags behind that of the therapeutic SRs; however, there are strong indications that this is changing.

Despite publications illustrating the importance of methodological quality in conducting and reporting both RCTs [14] and SRs [15], not all SRs are created using the same rigorous methods described above. Like most other research, variable methodological quality has been identified in systematic reviews. High-quality SRs of therapies attempt to identify the literature on a specific therapeutic intervention using a structured, a priori and welldefined methodology contained in a protocol. Rigorously conducted SRs are recognizable by their avoidance of publication and selection bias. For example, they include foreign language, both published and unpublished literature, and employ well-described comprehensive search strategies to avoid publication bias. Their trial selection includes studies with similar populations, interventions/controls, outcomes and methodologies and use of more than one “reviewer” to select included studies.

Systematic reviews regarding therapy would most commonly combine evidence from RCTs. In the event that statistical pooling is possible and clinically appropriate, the resultant pooled estimate represents the best “summary estimate” of the treatment effect. A systematic review with summary pooled statistics is referred to as a meta-analysis, while one is without summary data is referred to as a qualitative systematic review. Both of these options represent valid approaches to reporting SRs and both are now increasingly commonly published in the medical literature.

In the field of emergency medicine, SRs have been evaluated and found to contain serious flaws that potentially introduce bias into their conclusions [16]. This is an alarming picture for the profession, and one that needs to be addressed by members as well as authors and journal editors. Most of this research was completed prior to the establishment of the QUOROM (Quality of Reporting of Meta-analyses) statement; however, recent evidence suggests that this situation has not resulted in dramatic improvements in the quality of published SRs [17]. Consequently, ED physicians must be vigilant in their search for and evaluation of SRs as they pertain to this field.

The Cochrane Collaboration

The Cochrane Collaboration, a multinational, volunteer, collaborative effort on the part of researchers, clinicians from all medical disciplines, and consumers, represents one source of high-quality systematic review information available to most clinicians with very little effort [18]. The Cochrane Library is a compendium of databases and related instructional tools. Assuch, itis the principal product of the large international volunteer effort in the Cochrane Collaboration.

Within the Collaboration, specific review groups are responsible for developing, completing and updating SRs in specific topic areas. For example, the Cochrane Airway Group (CAG: www.cochrane-airways.ac.uk) is responsible for “airway” topics (e.g., asthma, chronic obstructive pulmonary disease, pulmonary embolism). Reviewers within the Cochrane review groups represent consumers, researchers, physicians, nurses, physiotherapists, educators and others interested in the topic areas. Not all review groups have produced acute care reviews; however, ED topics are particularly well covered by some (e.g., CAG) [19]. Recently the relevance of the Cochrane Collaboration effort to emergency medicine has been enhanced through the advent of the Cochrane Prehospital and Emergency Health Field (CPEHF: www.cochranepehf.org), which is expected to substantially increase the number of reviews with direct relevance to this specialty [20].

Systematic reviews produced by members of the Cochrane Collaboration are the products of a priori research protocols, meet rigorous methodological standards, and are peer reviewed for content and methods prior to dissemination. Specifically, this process of review production is designed to reduce bias and ensure validity, using criteria discussed in the JAMA User’s Guide series [21]. As much as possible, this text book will focus on evidence derived from SRs, and as often as possible, those contained within the Cochrane Library.

The Cochrane Library and emergency medicine

The Cochrane Library is comprised of several databases, three of which deserve some description and discussion here as they relate to this EBEM textbook. The Cochrane Central Register of Controlled Trials (CENTRAL) is an extensive bibliographic database of controlled trials that has been identified through structured searches of electronic databases, and hand-searching by Cochrane review groups. Currently, it contains over 300,000 references (Cochrane Library, 2007, Issue 4) and can function as a primary literature searching approach with therapeutic topics. The Database of Abstracts of Reviews of Effects (DARE) consists of critically appraised structured abstracts of non-Cochrane published reviews that meet standards set by the Centre for Reviews and Dissemination at the University of York, England. Currently, DARE contains over 3500 reviews (Cochrane Library, 2007, Issue 4). The last, and possibly most important, resource is the Cochrane Database of Systematic Reviews (CDSR), a compilation of regularly updated SRs with meta-analytic summary statistics. Currently, the CDSR contains over 1200 protocols and 3500 completed reviews (Cochrane Library, 2007, Issue 4). Contents of the CDSR are contributed by Cochrane review groups, representing various medical topic areas (e.g., airways, stroke, heart, epilepsy, etc.). Within the CDSR, “protocols” describe the objectives of SRs that are in the process of being completed; “completed reviews” include the full text, and usually present summary statistics. Both protocols and reviews are produced using a priori criteria, adhere to rigorous methodological standards and undergo peer review prior to publication. Regular “updates” are required to capture new evidence and address criticisms and/or identified errors.

The quality of systematic reviews contained with in the Cochrane Library has been shown to be consistently high for individual topic areas as well as throughout the Cochrane Collaboration [22,23]. Recent evidence evaluated the quality of a random selection of SRs published in 2004 and, long after the production of the QUOROM guidelines, found some intriguing results [24]. First and foremost, the volume of SRs identified suggested a rapid proliferation of SRs in health care. Second, 71% of the reviews involved a therapeutic area, recapitulating our previous comment about SRs being less common in diagnostic areas. Finally, there were large differences identified between Cochrane and non-Cochrane reviews in the quality of reporting several important characteristics; Cochrane reviews were rated as higher quality. Overall, the reviewers reiterated the variable quality of some reviews in the literature and the need to be cautious when using these reviews in health care decisions.

Prehospital and emergency medicine involvement has been limited across the Cochrane Collaboration and in many review groups, consequently topics of interest to emergency physicians have perhaps not been a priority. The development of the CPEHF in 2004 was an important milestone for evidence-based prehospital and emergency medicine [25]. CPHEF was registered as an official entity of the Cochrane Collaboration and now has more than 3000 registered members (F. Archer, personal communication). The focus of CPEHF is prehospital (management up to the delivery in the emergency department), emergency (up to hospitalization) and disaster medicine. One of the functions of the field is to develop and maintain a register of studies relevant to the areas of prehospital and emergency health care. CPEHF has developed a validated search strategy to identify SRs and reports of trials in the Cochrane Library that are based on research that was conducted in the prehospital environment [26].

Evidence-based Emergency Medicine format

We are excited about highlighting the approaches to the diagnosis and treatment of common emergency conditions that will be detailed in this book. The editors of Evidence-based Emergency Medicine have attempted to select experts in both emergency medicine (content) as well as evidence-based medicine (methodology) to author thistext. Followingthisintroductory section, the remainder of the chapters will focus on individual topic areas.

The chapters in this book have all been organized in a similar fashion using the following format:

1 Case scenario/vignette