ACLS Study Guide

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ACLS

STUDY GUIDE

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ACLS

STUDY GUIDE

Barbara Aehlert, MSEd, BSPA, RN

FIFTH EDITION

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3251 Riverport Lane 3251 Riverport Lane St. Louis, Missouri 63043 St. Louis, Missouri 63043 ACLS

ACLS STUDY STUDY GUIDE, FIFTH GUIDE, FIFTH EDITION EDITION ISBN: ISBN: 978-0-323-40114-2978-0-323-40114-2 Copyright

Previous editions copyrighted 2012, 2007, 2002. Previous editions copyrighted 2012, 2007, 2002.

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Notices Notices

Knowl

Knowledge and edge and best practice in this best practice in this field are field are constaconstantly changingntly changing. As . As new research and new research and experieexperience broadennce broaden our understandin

our understanding, changes g, changes in research methods, professional practicein research methods, professional practices, or s, or medical treatmenmedical treatment t may becomemay become necessary.

necessary. Practi

Practitioners and researchers must always rely tioners and researchers must always rely on their own on their own experieexperience and nce and knowleknowledge in dge in evaluatevaluating anding and using any

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With respect respect to to any any drug drug or or pharmaceutical pharmaceutical products products identified, identified, readers readers are are advised advised to to check check the the most most current information provided (i) on procedures featured or (ii) by the manufacturer of each product to be current information provided (i) on procedures featured or (ii) by the manufacturer of each product to be administ

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contraindicatindications. It ions. It is is the responsibilthe responsibility of ity of practipractitionerstioners, , relyinrelying g on their on their own experience and own experience and knowledknowledge of ge of their patients

their patients, to , to make diagnoses, to determine dosages and make diagnoses, to determine dosages and the best treatment for the best treatment for each individual patienteach individual patient,, and to

and to take all appropriate safety precautitake all appropriate safety precautions.ons. To

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As Stiggins has observed,

As Stiggins has observed, “ “Many of us grew up in classrooms in which our teachers believed that the way Many of us grew up in classrooms in which our teachers believed that the way

you maximize

you maximize learning ilearning is by s by maximizing anxiety. maximizing anxiety. Assessment was Assessment was always the always the intimidator. intimidator. Many of Many of our our teachers believed that if a little intimidation doesn

teachers believed that if a little intimidation doesn’’t work, turn up the heat t work, turn up the heat ——try a lot of intimidation.try a lot of intimidation.

This is why

This is why most adults today most adults today feel that being feel that being evaluated is a distinevaluated is a distinctly dangerous enterprise. It ctly dangerous enterprise. It always left always left us feeling vulnerable

us feeling vulnerable”” (Stiggins, 2005, p. 18 (Stiggins, 2005, p. 18* * ).).

I took my first Advanced Cardiac Life Support (ACLS) class many years ago. I felt terrified and lost I took my first Advanced Cardiac Life Support (ACLS) class many years ago. I felt terrified and lost thr

throughoughoutout thethe ententireire coucourserse.. AltAlthouhoughgh II hadhad spespentnt weeweeksks stustudyidyingng befbeforeore thethe coucourserse begbegan,an, matmaterierialal now now seemed to be written in a foreign language. I could find no resources to

seemed to be written in a foreign language. I could find no resources to““translatetranslate”” the information into the information into

somet

somethinghing that that waswas usefuuseful to l to me.me. TheThe courscoursee consisconsisted ted ofof very very long long lecturlectures bes byy instruinstructorsctors whowho read read slidesslides and offered little useful insight. The most memorable part of the course was the

and offered little useful insight. The most memorable part of the course was the “ “Patient Management Patient Management ””

station, in which each course participant was evaluated one-on-one by an instructor. (Those of you who station, in which each course participant was evaluated one-on-one by an instructor. (Those of you who ha

haveve bebeenen ararououndnd aa whwhileareileare prprobobabablyly hahavivingng flflasashbhbacacksks ofof ththososee dadaysys.).) II wiwillll never never forgeforgett thatthat experexperience.ience. Despite my preparation, as soon as the door closed behind me I was a mental wreck. The instructor Despite my preparation, as soon as the door closed behind me I was a mental wreck. The instructor proceeded to methodically strip away any self-confidence I might have had in treating patients with proceeded to methodically strip away any self-confidence I might have had in treating patients with car-diac eme

diac emergenciergencies. Is. I was able to answas able to answer the quewer the questions askstions askeded of me until Iof me until I waswas presepresented with a patinted with a patient whoent who had symptomatic bradycardia. Atropine had not worked (transcutaneous pacing was not readily available had symptomatic bradycardia. Atropine had not worked (transcutaneous pacing was not readily available back then), and the next drug recommended at that time was isoproterenol. I knew that. What I could back then), and the next drug recommended at that time was isoproterenol. I knew that. What I could not recall was whether isoproterenol was given in mcg/min (correct) or mg/min. I took a

not recall was whether isoproterenol was given in mcg/min (correct) or mg/min. I took a ““50/5050/50”” guess guess

and said mg/min. Because that was the wrong decision, I was told I had failed and would need to attend and said mg/min. Because that was the wrong decision, I was told I had failed and would need to attend another 2-day course.

another 2-day course.

Before driving home, I sat outside for a few minutes contemplating what had happened and what I Before driving home, I sat outside for a few minutes contemplating what had happened and what I might have done to change the outcome. Then and there, promised myself I would become an ACLS might have done to change the outcome. Then and there, promised myself I would become an ACLS instr

instructor uctor somedasomedayy and and find find aa wayway to to teach teach thisthis informinformation ation inin aa moremore user-user-friendfriendly ly way.way. II vowed vowed to to teachteach courses that were useful to practicing health care professionals and delivered in an environment in which courses that were useful to practicing health care professionals and delivered in an environment in which the participants looked forward to the class

the participants looked forward to the class——instead of dreading it.instead of dreading it.

As

As thethe yearsyears passed,passed, II diddid become anbecome an ACLSACLS instructorinstructor andand II lovedloved it.it. AtAt thethe conclusionconclusion ofof eacheach course,course, par

particticipaipantsnts oftoftenen wrowrotete onon thetheirir evaevalualuatiotionn forformsms thathatt aa stustudydy guiguidede wouwouldld havhavee beebeenn helhelpfupfull inin prepreparparing ing for class. Those suggestions resulted in my writing a few pages of information that ultimately became a for class. Those suggestions resulted in my writing a few pages of information that ultimately became a book

book ——this this book. book.

The

The ACLS Study Guide ACLS Study Guide is a course preparation tool designed for paramedic, nursing, and medical is a course preparation tool designed for paramedic, nursing, and medical students, ECG monitor technicians, nurses, and other allied health personnel working in emergency students, ECG monitor technicians, nurses, and other allied health personnel working in emergency dep

departartmenments,ts, cricriticticalal carcaree uniunits,ts, pospostantanestestheshesiaia carcaree uniunits,ts, opeoperatratinging roorooms,ms, andand teltelemeemetrytry uniunits.ts. TheThe fiffifthth edition of this book is based on the following scientific principles, treatment recommendations, and edition of this book is based on the following scientific principles, treatment recommendations, and guidelines:

guidelines:

•• 2015 American Heart Association Guidelines for Car2015 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency diopulmonary Resuscitation and Emergency

Cardiovascular Care Cardiovascular Care

•• 2015 Internatio2015 International nal ConseConsensus nsus on on CardiCardiopulmoopulmonary Resuscitanary Resuscitation tion and and EmergEmergency Cardiovasency Cardiovascular cular

Care Science with Treatment Recommendations Care Science with Treatment Recommendations

•• Other evidence-based treatment recommendations or sources cited in the references section of rele-Other evidence-based treatment recommendations or sources cited in the references section of

rele- vant

vant chapters.chapters.

* *

Stig

Stiggingins,s, R.R. J.J. (20(2005)05).. An introdu An introduction to ction to student-involstudent-involved assessment for ved assessment for learning learning (5th(5th ed.).Uppered.).Upper SaddSaddlele RiverRiver,, NJ:NJ: PearPearsonson PrentPrenticeice Hall.

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This book is designed for use with the American Safety and Health Institute (ASHI) ACLS Course. It can also be used as supplementary material by those participating in ACLS courses offered by other organizations.

I have made every attempt to provide information consistent with the current literature, including the latest resuscitation guidelines; however, medicine is a dynamic field. Resuscitation guidelines change, new medications and technology are being developed, and medical research is ongoing. As a result, be sure to learn and follow local protocols as defined by your medical advisors. The author and publisher assume no responsibility or liability for loss or damage resulting from the use of information contained within.

I genuinely hope the content of this book is helpful to you, and I wish you success in your ACLS course and clinical practice.

Sincerely,

Barbara Aehlert vi Preface to the Fifth Edition

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My sincerest thanks to Melissa Kinsey for her guidance throughout the development of this text. A spe-cial thanks to the manuscript reviewers who provided insightful comments and suggestions.

A special thanks to these instructors, who share my ACLS teaching philosophy: Robert Aiken, CEP; Andrew Baird, CEP; Eileen Blackstone, CEP; Lynn Browne-Wagner, RN; Randy Budd, CEP; Joanna

Burgan, CEP; Thomas Cole, CEP; Mike Connor, CEP; Paul Honeywell, CEP; James Johnson, CEP; Stephen Knox, CEP; Bill Loughran, RN; Terence Mason, RN; Kevin McColm, CEP; Sean Newton, CEP; Anthony Pino, RN; Jan Post, RN; Gary Smith, MD; Ed Tirone, CEP; and Maryalice Witzel, RN.

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N.K. Alexander, EMT-P

Instructor/Chief Operating Officer Wilton Emergency Squad, Inc

Saratoga Springs, New York B. Cetanyan, RN

Eastern Iowa Community College Davenport, Iowa

F.O. Garcia, EMT-P President

Professional EMS Education, LLC Grand Junction, Colorado

C. Horsfield, BA

Paramedic Teaching Fellow School of Health Sciences University of Surrey Guildford, Surrey, UK

J.A. Nelson, DO, MS, FACOEP, FACEP State EMS Medical Director

Florida Department of Health Tallahassee, Florida

S.L. Pinski, MD

Head, Section of Cardiac Pacing and Electrophysiology

Robert and Suzanne Tomsich Department of Cardiology

Cleveland Clinic Florida Weston, Florida

B.R. Shade, EMT-P, EMS-I, AAS

AHA Program Instructor, Adjunct Faculty, Firefighter

Paramedic, retired Assistant Safety Director Cleveland Clinic, Cuyahoga Community College,

Willoughby Fire Department, City of Cleveland

Cleveland, Ohio

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Barbara Aehlert, MSEd, BSPA, RN, has been a registered nurse for more than 40 years, with clinical experience in medical/surgical nursing, critical care nursing, prehospital education, and nursing educa-tion. Barbara is an active CPR and ACLS instructor with a special interest in teaching basic dysrhythmia recognition and ACLS to nurses and paramedics.

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1 Emergency Cardiovascular Care 1

Introduction 1

Sudden Cardiac Death 2

Out-of-Hospital Cardiac Arrest 4

In-Hospital Cardiac Arrest 5

ChainofSurvival 5

Out-of-Hospital Chain of Survival 5

In-Hospital Chain of Survival 8

Cardiopulmonary Resuscitation 10

Physiology of Chest Compressions 10

Barriers to Effective Cardiopulmonary Resuscitation 10 Feedback during Cardiopulmonary Resuscitation 11

Mechanical Chest Compression Devices 12

Patient Assessment 14

PrimarySurvey 15

Secondary Survey 17

Putting It All Together 18

Chapter Quiz 18

Chapter Quiz Answers 19

References 20 2 Airway Management 23 Introduction 23 Anatomy Review 25 Upper Airway 25 Lower Airway 27

The Patient with Respiratory Compromise 28

Patient Assessment 29

Oxygen Delivery Devices 32

NasalCannula 33

Simple Face Mask 34

Partial Rebreather Mask 35

Nonrebreather Mask 36

Manual Airway Maneuvers 37

Head Tilt –ChinLift 37

Jaw Thrust 38 Suctioning 39 Airway Adjuncts 40 OralAirway 40 NasalAirway 42

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Positive Pressure Ventilation 44 Noninvasive Positive Pressure Ventilation 44

Mouth-to-Mask Ventilation 45

Bag-Mask Ventilation 47

Advanced Airways 49

Confirming Endotracheal Tube Placement 51

Chapter Quiz 53

References 60

3 Cardiac Anatomy and Electrophysiology 63

Introduction 63

Coronary Arteries 65

CardiacCells 66

Cardiac Action Potential 66

Depolarization 67

Repolarization 67

Phases of the Cardiac Action Potential 67

Refractory Periods 68

Conduction System 69

Sinoatrial Node 69

Atrioventricular Node and Bundle 70

Right and Left Bundle Branches 70

PurkinjeFibers 70

The Electrocardiogram 71

Electrodes 72

Leads 72

Electrocardiography Paper 76

Waveforms and Complexes 76

Segments and Intervals 77

Acute Coronary Syndromes 78

Chapter Quiz 79

References 81

4 Cardiac Arrest Rhythms 83

Introduction 83

Cardiac Arrest Rhythms 84

Ventricular Tachycardia 85

Ventricular Fibrillation 85

Asystole 88

Pulseless Electrical Activity 90

Defibrillation 91

Monophasic versus Biphasic Defibrillation 93

Transthoracic Impedance 94

Defibrillation Procedure 97

Automated External Defibrillation 99

Automated External Cardioverter-Defibrillators 100

Possible Complications 100

The Resuscitation Team 100

Team Leader Responsibilities 101

Team Member Responsibilities 102

Resuscitation Efforts 104

Helping the Caregivers 112

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Chapter Quiz 113

References 125 5 Tachycardias 129 Introduction 129 Narrow-QRS Tachycardias 131 Sinus Tachycardia 131 Supraventricular Tachycardia 132 Wide-QRS Tachycardias 140 Ventricular Tachycardia 142 Irregular Tachycardias 143

Multifocal Atrial Tachycardia 143

Atrial Flutter 144

Atrial Fibrillation 145

Polymorphic Ventricular Tachycardia 148

Synchronized Cardioversion 150

Procedure 150

Chapter Quiz 153

References 165

6 Bradycardias 167

Introduction 167

Sinus Bradycardia 169

Junctional Escape Rhythm 169

Ventricular Escape Rhythm 171

Atrioventricular Blocks 172

First-Degree Atrioventricular Block 172

Second-Degree Atrioventricular Blocks 173

Third-Degree Atrioventricular Block 176

Transcutaneous Pacing 176

Indications 177

Procedure 178

Limitations 179

Possible Complications 180

Chapter Quiz 181

References 191

7 Acute Coronary Syndromes 193

Introduction 193

Pathophysiology of Acute Coronary Syndromes 194 Myocardial Ischemia, Injury, and Infarction 196

Myocardial Ischemia 196

Myocardial Injury 199

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Patient Evaluation 201 Patient History 201 Atypical Presentation 202 Physical Examination 203 Electrocardiogram Findings 204 Cardiac Biomarkers 214 Imaging Studies 215

Initial Management of Acute Coronary Syndromes 215

Prehospital Management 215

Emergency Department Management 216

Pharmacologic Therapies 217

Reperfusion Therapies 224

Chapter Quiz 227

References 235

8 Acute Ischemic Stroke 237

Introduction 237 Definition of Stroke 239 Anatomy Review 239 Stroke Types 240 Subarachnoid Hemorrhage 240 Intracerebral Hemorrhage 241 Ischemic Stroke 242

Transient Ischemic Attack 243

Stroke Systems of Care 243

Public Education 244

Emergency Medical Services 244

Stroke Centers 246

Chapter Quiz 251

References 256

9 PostTest 259

Post test Answers 269

References 276

Glossary

277

Index

281

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1 Emergency

Cardiovascular Care

INTRODUCTION

Heart disease is a broad term that refers to conditions that affect the heart, and it is a leading cause of death forboth men and women in the United States. Because someonein the United States experiences a coronary event every 25 seconds, the likelihood of encountering a patient who requires basic life support (BLS) or advanced cardiac life support (ACLS) care is high ( Roger, et al., 2012).

Just as BLS is a systematic way of providing care to a choking victim or to someone who needs car-diopulmonary resuscitation (CPR), ACLS is an orderly approach to providing advanced emergency care to a patient who is experiencing a cardiac-related problem. This chapter discusses risk factors for coronary artery disease (CAD), sudden cardiac death (SCD), the Chain of Survival, and a systematic approach to patient assessment.

D E S I R E D R E S U L T S

GOAL Given a patient situation, and working in a team setting, direct or perform an initial patient assessment, identify common barriers to effective CPR, and identify actions that can be taken to

overcome them.

L E A R N I N G O B J E C T I V E S

After completing this chapter, you should be able to:

1. _{Define cardiovascular collapse, cardiac arrest, sudden cardiac death, and sudden cardiac}

arrest.

2._{Discuss the phases of a cardiac arrest.}

3._{Discuss the prearrest factors that influence survival in out-of-hospital cardiac}

arrest (OHCA).

4. _{Identify the initial cardiac rhythms that are typically recorded in OHCA.}

5._{Discuss the prearrest factors that influence survival in in-hospital cardiac arrest (IHCA).} 6. _{Identify the initial cardiac rhythms that are typically recorded in IHCA.}

7._{Describe the links in the Chain of Survival.}

8._{Discuss the requirements for performing high-quality CPR.}

9. _{Discuss common barriers to effective CPR and possible actions that can be taken to}

overcome them.

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11._{Discuss the use of continuous end-tidal carbon dioxide (EtCO}₂_{) monitoring during}

resuscitation efforts.

12._{Discuss the use of mechanical chest compression devices during resuscitation efforts.} 13. _{State three areas to assess when forming a general impression of a patient.}

14._{Differentiate between the purposes and components of the primary and secondary}

surveys.

15._{Discuss a systematic approach to the initial emergency care of an unresponsive patient.}

L E A R N I N G P L A N

• Whether you are preparing for your first ACLS course or your tenth, schedule time to study

and review before the course. Studying in half-hour intervals with 10-minute breaks allows a reasonable period for both learning and relaxation.

• Read this chapter before class. Take the time to highlight important concepts as you read. • Develop and use flashcards, flowcharts, and mnemonics to help enhance your retention of

the information presented.

• Complete the chapter quiz and review the quiz answers provided.

K E Y T E R M S

Automated external defibrillator (AED) A machine with a sophisticated computer system that analyzes a patient’s heart rhythm using an algorithm to distinguish shockable rhythms

from nonshockable rhythms and provides visual and auditory instructions to the rescuer to deliver an electrical shock if a shock is indicated.

Cardiopulmonary (cardiac) arrest The absence of cardiac mechanical activity, which is confirmed by the absence of a detectable pulse, unresponsiveness, and apnea or agonal, gasping breathing.

Cardiovascular collapse A sudden loss of effective blood flow that is caused by cardiac and/ or peripheral vascular factors that may reverse spontaneously (eg, syncope) or only with interventions (eg, cardiac arrest).

Cardiovascular disease (CVD) A collection of conditions that involve the circulatory system, which contains the heart (cardio) and blood vessels (vascular), including congenital cardiovascular diseases.

Chain of Survival The essential elements of a system of care that are necessary to link the victim of sudden cardiac arrest with survival.

Coronary artery disease (CAD) Disease affecting the arteries that supply the heart muscle with blood.

Coronary heart disease (CHD) Disease of the coronary arteries and resulting complications, such as angina pectoris and acute myocardial infarction.

Heart disease A broad term that refers to conditions affecting the heart.

Risk factors Traits and lifestyle habits that may increase a person’s chance of developing a

disease.

Sudden cardiac death (SCD) A natural death of cardiac cause that is preceded by an abrupt loss of consciousness within 1 hour of the onset of an acute change in cardiovascular status; sudden cardiac arrest _{is a term commonly applied to such an event when the patient}

survives.

SUDDEN CARDIAC DEATH

[Objectives 1, 2]

Cardiovascular disease (CVD) is a collection of conditions that involve the circulatory system, which contains the heart (cardio) and blood vessels (vascular), including congenital CVD. More than one in three American adults has one or more types of cardiovascular disease (Roger, et al., 2012). The preven-tion of CVD requires the management of risk factors. Risk factors are traits and lifestyle habits that may increase a person’s chance of developing a disease. Some risk factors can be modified by specific,

2

CHAPTER 1 Emergency Cardiovascular Care

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preventable measures. Risk factors that cannot be modified are called nonmodifiable or fixed risk factors. Contributing risk factors are thought to lead to an increased risk of heart disease, but their exact role has not been defined ( Table 1.1).

Coronary heart disease (CHD) refers to disease of the coronary arteries and resulting complications, such as angina pectoris and acute myocardial infarction. Approximately one of every six deaths in the United States was caused by CHD in 2008 (Roger, et al., 2012). Coronary artery disease (CAD) affects the arteries that supply the heart muscle with blood. More than 90% of CAD events occur in individuals who have at least one risk factor (Mack & Gopal, 2014). The relationships among CAD and its major

sequelae are shown in Fig. 1.1.

Cardiovascular collapse is a sudden loss of effective blood flow caused by cardiac factors, peripheral vascular factors, or both, that may reverse spontaneously (eg, syncope) or only with interventions

(eg, cardiac arrest) (Myerburg & Castellanos, 2012). Cardiopulmonary (cardiac) arrest is the absence of cardiac mechanical activity, which is confirmed by the absence of a detectable pulse, unresponsiveness, and apnea or agonal, gasping breathing. Gasping is abnormal breathing, is common during the first few minutes of primary cardiac arrest, and is a sign of adequate blood flow to the brainstem (Ewy, 2012). Respiratory efforts can persist for 1 minute or longer after the onset of a cardiac arrest (Myerburg & Castellanos, 2012).

TABLE 1.1

_{Cardiovascular Disease Risk Factors}

Nonmodifiable (Fixed) Factors Modifiable Factors Contributing Factors

• Age

• Family history of cardiovascular

disease

• Gender • Race

• Diabetes mellitus

• Elevated serum cholesterol levels • Hypertension

• Metabolic syndrome • Obesity

• Physical inactivity • Tobacco exposure • Unhealthy dietary habits

• Alcohol intake

• Inflammatory markers • Psychosocial factors • Sleep apnea

• Stress

CORONARY ARTERY DISEASE

Chronic ischemic heart disease

Congestive heart failure Myocardial ischemia Acute plaque change; coronary artery thrombosis MYOCARDIAL INFARCTION

with muscle loss and arrhythmias Ventricular remodeling Infarct healing Hypertrophy, dilation of viable muscle Myocardial ischemia of increased severity and duration

SUDDEN CARDIAC DEATH

Fig. 1.1 The relationships among coronary artery disease and its major sequelae. (From Kumar V, Abbas AK, Aster JC: Rob- bins basic pathology , ed 9, Philadelphia, 2013, Saunders.)

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Sudden cardiac death (SCD) is a natural death of cardiac cause that is preceded by an abrupt loss of consciousness within 1 hour of the onset of an acute change in cardiovascular status ( Myerburg & Castellanos, 2012). SCD is often the patient ’s first and only symptom of heart disease (O’Connor,

et al., 2010). For others, warning signs may be present up to 1 hour before the actual arrest. Sudden cardiac arrest is a term commonly applied to such an event when the patient survives ( Taniguchi, et al., 2012). Four phases of cardiac arrest have been described, each with unique physiology and treatment strategies ( Topjian, et al., 2013) ( Table 1.2).

Heart rhythms that may be observed in a cardiac arrest include the following:

1. Pulseless ventricular tachycardia (pVT), in which the electrocardiogram (ECG) displays a wide, reg-ular QRS complex at a rate faster than 120 beats per minute (beats/min).

2. Ventricular fibrillation (VF), in which irregular chaotic deflections that vary in shape and height are observed on the ECG but there is no coordinated ventricular contraction.

3. Asystole, in which no cardiac electrical activity is present.

4. Pulseless electrical activity (PEA), in which electrical activity is visible on the ECG but central pulses are absent.

pVT and VF are shockable rhythms. This means that delivering a shock to the heart by means of a defibrillator may result in termination of the rhythm. Asystole and PEA are nonshockable rhythms.

Out-of-Hospital Cardiac Arrest

[Objectives 3, 4]

Most nontraumatic OHCAs in the United States are the result of a primary cardiac arrest, rather than secondary to respiratory arrest (Ewy & Bobrow, 2016). A primary cardiac arrest is an unexpected wit-nessed (ie, seen or heard) collapse in an individual who is not responsive (Ewy, 2012). Seventy percent of nontraumatic OHCAs occur in the home (Centers for Disease Control and Prevention, 2014). Of these arrests, 50.3% are unwitnessed, 37.7% are witnessed by a bystander, and 12.1% are witnessed by a 9-1-1 responder (Centers for Disease Control and Prevention, 2014).

Prearrest factors that influence survival in OHCA include the following (Boyd & Perina, 2012; Martinez, 2012):

• Performance of bystander CPR

• Mode of arrest (ie, respiratory versus cardiac) • Witnessed arrest

• Age (older age associated with worsened survival) • Initial presenting rhythm of VF

• Short response times to defibrillation

• Location of the arrest (survival is 3 to 4 times more likely if an arrest occurs in a public place; survival is

6 times more likely if the arrest occurs in the workplace)

• Time of day (peak incidence occurs between 8 am and 10 am; survival to hospital discharge lowest for

arrests between midnight and 6 am)

When an OHCA occurs, the initial rhythm recorded by emergency personnel is generally considered the electrical mechanism of the arrest (Myerburg & Castellanos, 2012). This information is important because it affects patient outcome. Patients who are in sustained VT at the time of initial contact have the

TABLE 1.2

_{Phases of Cardiac Arrest}

Phase Interval Focus of Care

Prearrest Period before the arrest Identify, anticipate, and manage factors that may result in cardiac arrest (eg, use of rapid response teams to recognize and treat patients at risk of deterioration) No flow Untreated cardiac arrest Prompt initiation of basic life support upon recognition of the

arrest by a bystander or health care professional Low flow Onset of cardiopulmonary

resuscitation

Delivery of high-quality chest compressions to optimize myocardial and cerebral perfusion

Postresuscitation Return of spontaneous circulation

Identify and treat the cause of the arrest, preserve

neurologic function, and support end organ perfusion and function

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best outcome, whereas those who present with a bradyarrhythmia or asystole at initial contact have the worst prognosis (Myerburg & Castellanos, 2012). When the initial rhythm recorded is VF, the patient ’s

outcome is intermediate between the outcomes associated with sustained VT and those of bradyarrhyth-mia and asystole (Myerburg & Castellanos, 2012). Data from nontraumatic OHCAs in 2014 indicate that asystole was the most common initial cardiac arrest rhythm (45.6%), followed by an idioventricular rhythm/PEA (21.4%), VF/pVT/unknown shockable rhythm (20.4%), and an unknown nonshockable rhythm (12.5%) (Centers for Disease Control and Prevention, 2014). Overall survival from nontraumatic OHCA to hospital admission was 28.3%, and overall survival to hospital discharge was 10.8% ( Centers for Disease Control and Prevention, 2014).

In-Hospital Cardiac Arrest

[Objectives 5, 6]

The most common causes of IHCA include cardiac arrhythmia, acute respiratory insufficiency, and hypotension (Morrison, et al., 2013) with predictable deterioration before the event (eg, tachypnea, tachycardia) (Kronick, et al., 2015). Prearrest factors that influence survival in IHCA include the follow-ing (Martinez, 2012):

• Initial presenting rhythm of VF

• Time to CPR and defibrillation (survival is 33% when CPR is started within 1 minute of arrest versus

14% if the time interval is greater than 1 minute; survival is 38% in pVT/VF arrests when defibrillation is performed within 3 minutes versus 21% if the time interval is greater than 3 minutes)

• Location (survival is highest if an arrest occurs in an intensive care unit [ICU; witnessed and

mon-itored arrest, advanced life support {ALS} immediately available], better survival rates for wards that have more than 5 cardiac arrests per year)

• Time of day (arrests that occur at night on general hospital wards have one-half the likelihood of

survival)

• AED use

With regard to adult IHCA, asystole and PEA are more common than VF or pVT as the initial rhythm (Morrison, et al., 2013). In a largestudy of adult IHCA patients, only 23% presented with shock-able rhythms ( Wallace, et al., 2013). An analysis of multicenter IHCAs published in 2010 observed that the onset of the IHCA was witnessed in 79.2% of instances and approximately 32% of IHCAs occurred within 24 hours of admission, 34% occurred within 1 week of admission, and 23% occurred more than

1 week after admission (Larkin, et al., 2010). Generally, IHCA has a better outcome than OHCA with 22.3% to 25.5% of adult patients surviving to discharge (Kleinman, et al., 2015).

The terms code and code blue are often used in hospitals when a patient experiences a respiratory arrest, a cardiac arrest, or a cardiac dysrhythmia that is associated with unresponsiveness. When a code blue is called, usually by means of an overhead paging system, a predesignated team of health care professionals is deployed to the patient ’s bedside to provide lifesaving interventions. The configuration of the

resus-citation team and the responsibilities of each team member are discussed in Chapter 4.

CHAIN OF SURVIVAL

[Objective 7]

The Chain of Survival represents the essential elements of a system of care that are necessary to link the victim of sudden cardiac arrest with survival. Although links of the Chain have been used for almost

25 years to depict the interrelated steps necessary with regard to an adult cardiac arrest both outside and inside the hospital setting, the 2015 resuscitation guidelines depict two separate chains because there are differences in these systems of care. Time is critical when dealing with a victim of sudden cardiac arrest; a weak or missing link in either Chain of Survival can reduce the likelihood of a positive outcome.

Out-of-Hospital Chain of Survival

[Objective 7]

The links in the out-of-hospital Chain of Survival for adults include early recognition and activation, early CPR, rapid defibrillation, effective ALS, and integrated post – cardiac arrest care.

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Early Recognition and Activation

The first link in the out-of-hospital Chain of Survival is early recognition and activation of the emergency medical services system (EMSS). When a cardiac emergency occurs, the patient (or a family member or bystander) must identify his or her signs and symptoms, recognize that they are related to a heart con-dition, and seek medical assistance in the hope of preventing cardiac arrest. Delays in seeking assistance and delays in the arrival of assistance ultimately affect patient outcome.

Emergency dispatchers, who are located at public service access points, are the link between the call for help and the arrival of medical assistance (Kronick, et al., 2015). Dispatchers are trained to recognize the caller ’s description of a potential heart attack or cardiac arrest and to provide real-time

CPR instructions over the phone if necessary while quickly sending appropriately trained and equipped emergency medical services (EMS) personnel to the scene. Some emergency medical dispatch protocols include telephone instructions for guiding an untrained rescuer in performing compression-only CPR. In some areas, emergency dispatchers have used social media to summon volunteer rescuers to the scene to provide bystander CPR until the arrival of EMS professionals

(Kronick, et al., 2015).

Early Cardiopulmonary Resuscitation

After recognizing that an emergency exists, the scene must be assessed to ensure that it is safe to enter. If the scene is safe, the patient must be quickly assessed for life-threatening conditions and the nature of the emergency determined.

CPR is a part of BLS. BLS includes the recognition of signs of cardiac arrest, heart attack, stroke, and foreign body airway obstruction (FBAO); the relief of FBAO; CPR; and defibrillation with an AED. BLS must be provided until advanced medical help arrives and assumes responsibility for the patient ’s

care. Necessary care may include the following:

• Patient positioning

• CPR for victims of cardiac arrest • Defibrillation with an AED

• Rescue breathing for victims of respiratory arrest • Recognition and relief of FBAO

If CPR is necessary, compressions on adult victims of cardiac arrest should be performed at a rate of 100 to 120 compressions/minute with a compression depth of at least 2 inches (5 cm) but no more than 2.4 inches (6 cm) (Kleinman, et al., 2015).

Rapid Defibrillation

When an individual experiences a cardiac arrest, the likelihood of successful resuscitation is affected by the speed with which CPR and defibrillation are performed. The goal for providing the first shock for sudden cardiac arrest resulting from VF or pVT is within 3 minutes of collapse (Link, et al., 2010).

The American Heart Association has promoted the development of AED programs to improve survival from sudden cardiac arrest since 1995. An automated external defibrillator (AED) is a machine with a sophisticated computer system that analyzes the patient ’s heart rhythm (Figs. 1.2 to 1.4).The AED

uses an algorithm to distinguish shockable rhythms from nonshockable rhythms. If the AED detects a shockable rhythm, it provides visual and auditory instructions to the rescuer to deliver an electrical shock. Defibrillation performed by citizens (such as flight attendants, casino security officers, athletic or golf club employees, and ushers at sporting events) at the scene is called public access defibrillation.

Some AEDs:

• Have CPR pads available that are equipped with a sensor that detects the rate and depth of chest

compressions. If the rate or depth of compressions is inadequate, the machine provides voice prompts to the rescuer.

• Provide voice instructions in adult and infant/child CPR at the user ’s option. A metronome function

encourages rescuers to perform chest compressions at the recommended rate per minute.

• Are programmed to detect spontaneous movement by the patient or others.

• Have adapters available for many popular manual defibrillators, enabling the AED pads to remain on

the patient when patient care is transferred.

• Can be configured to allow ALS personnel to switch to a manual mode, allowing more

decision-making control.

• Are equipped with a small screen that allows the rescuer to view the patient ’s cardiac rhythm, assisting

in identification of shockable versus nonshockable rhythms.

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Fig. 1.3 The Cardiac Science Powerheart G3 Plus automated external defibrillator. (Courtesy Cardiac Science Corporation, Waukesha, WI)

Fig. 1.4 The LIFEPAK ®1000 Defibrillator. (Courtesy Physio-Control, Inc., Redmond, WA)

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• Can detect the patient ’s transthoracic resistance through the adhesive pads applied to the patient ’s

chest. The AED automatically adjusts the voltage and length of the shock, thus customizing how the energy is delivered to that patient.

• Are equipped with a pediatric attenuator (ie, a pad-cable system or key). When the attenuator is

attached to the AED, the machine recognizes the pediatric cable connection and automatically adjusts its defibrillation energy accordingly.

Defibrillation is discussed in more detail in Chapter 4. Effective Advanced Life Support

Outside the hospital, early advanced care is provided by paramedics (and/or nurses) arriving on the scene. Prehospital professionals work quickly to stabilize the patient by providing ventilation support, vascular access, and giving emergency medications, among other interventions.

Integration of Post

_–

Cardiac Arrest Care

Prehospital professionals transportand then transfer the patient to the closest most appropriate emergency department (ED) or directly to a specialized cardiac arrest center where definitive care can be provided.

In-Hospital Chain of Survival

[Objective 7]

The links in the in-hospital Chain of Survival for adults include surveillance and prevention of cardiac arrest, prompt notification and response when a cardiac arrest occurs, the performance of high-quality CPR, prompt defibrillation, and intra-arrest and post – cardiac arrest care (Kronick, et al., 2015). Surveillance and Prevention

A cardiac arrest experienced by a hospitalized adult is often preceded by warning signs and symptoms that suggest physiologic deterioration such as tachypnea, tachycardia, and hypotension ( Tibballs & van der Jagt, 2008). Recognizing that early detection and treatment of the patient who demonstrates signs of clinical deterioration may prevent cardiac arrest and improve patient outcome, the concept of a Rapid Response System (RRS) emerged. The RRS is mobilized by other hospital staff based on predetermined criteria for activation of the team. The Joint Commission National Patient Safety Goals require hospitals to implement systems that enable health care workers to directly request additional assistance from spe-cially trained individuals when the patient ’s condition appears to be worsening ( Joint Commission on

Accreditation of Healthcare Organizations, 2007).

Several types of responding teams exist, and large hospitals may require more than one response team. It has been suggested that the term medical emergency team (MET) be used for teams that are generally led by physicians and have the ability to: (1) prescribe therapy; (2) place central vascular lines; (3) initiate ICU-level care at the bedside; and (4) perform advanced airway management (Devita, et al., 2006; McCurdy & Wood, 2012). It is recommended that the term rapid response team (RRT) be used to describe a team without all four of those abilities that performs a preliminary evaluation of a patient and summons additional help or facilitates patient transfer to a higher level of care if warranted (McCurdy & Wood, 2012). RRTs typically consist of multidisciplinary members such as a physician (eg, critical care or hospitalist), a critical care nurse, and a respiratory therapist who respond to emergen-cies, proactively identify and evaluate patients at risk for decompensation, educate and act as a liaison to ward staff, and follow up on patients who have been discharged from the ICU. In addition to their role in

identifying prearrest conditions, studies have shown that MET and RRT services have also contributed to the detection and management of medical errors, surgical postoperative morbidity, and clarification of do not resuscitate status ( Tibballs & van der Jagt, 2008).

Several scoring systems for detecting warning signs of patient deterioration exist, and they are used as tools to assist in determining when the RRT should be activated. For example, with one type of scoring system, the RRT is activated when a single vital sign or clinical abnormality is outside a predetermined range (Box 1.1). With the Modified Early Warning Score (MEWS) points are assigned based on the degree of derangement of ventilatory rate, heart rate, systolic blood pressure (BP), mental status, temper-ature, and hourly urine output. Regardless of the type of scoring system used, the decision to activate the RRT based on a score is ultimately the responsibility of the bedside clinician (McCurdy & Wood, 2012).

Adoption of an RRT necessitates teaching and staff empowerment because it usually “involves

substituting a traditional response reserved for cardiac or respiratory arrest (eg, Code Blue) with a system that responds to the early onset of signs and symptoms that may lead to these conditions”( Tibballs & van

8

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der Jagt, 2008). Barriers to activation of the RRT by nurses have been identified and include the follow-ing (McCurdy & Wood, 2012):

• The nurse may not know whom to contact when a patient ’s condition deteriorates. • The nurse may fear blame if activation of the RRS is later deemed unnecessary.

• Nurses often observe patients who briefly exhibit abnormal vital signs that spontaneously normalize.

Even when a dedicated response team exists within an institution, such teams are usually not imme-diately available and most medical emergencies must be managed by ad-hoc teams (Monteleone & Lin, 2012). After-hours cardiac arrests (ie, evening and weekend) are associated with twice the mortality of office-hour arrests, which is thought to be a result of both the availability and the experience of staff (Herlitz, et al., 2002; Monteleone & Lin, 2012).

Studies show considerable variation in patient outcome data with regard to the use of RRTs. In adults, some studies demonstrate reductions in both IHCA and mortality, others demonstrate reductions in IHCA without a significant change in mortality, and still others show no significant differences in either IHCA or mortality (McCurdy & Wood, 2012). The 2015 resuscitation guidelines note that for adult patients, RRTs or MET systems can be effective in reducing the incidence of cardiac arrest, particularly in general care wards; pediatric MET/RRT systems may be considered in facilities where children with high-risk illnesses are cared for on general in-patient units; and the use of early warning sign systems may be considered for adults and children (Kronick, et al., 2015).

Notification and Response

Every member of the hospital staff should know how to recognize a cardiac arrest and know how to sum-mon assistance when such an event occurs. Prompt notification and activation of the code team may include pressing a “code button” at the patient ’s bedside, calling a specific phone extension, or use of a “quick dial button” located on telephones within the facility. When the operator is reached, the type

of emergency and its location are stated. Once the operator is notified of the emergency, members of the code team typically are activated by means of cell phones and/or a hospital-wide public address system.

Cardiopulmonary Resuscitation

Although cardiac arrests and the performance of CPR are relatively uncommon in in-hospital environ-ments (Kronick, et al., 2015), it is essential that hospital staff be able to perform high-quality CPR. Because training may not be adequate to ensure optimal performance, strategies such as timely access to equipment, visual reminders, regular testing, and point-of-care feedback have been suggested as methods to improve the translation of resuscitation guidelines into practice during cardiac arrest (Morrison, et al., 2013).

Prompt Defibrillation

It has been estimated that about half of all IHCAs occur outside the ICU ( Morrison, et al., 2013). Because it can take several minutes for code team members to arrive with a defibrillator, the strategic deployment of AEDs throughout the facility can aid in achieving prompt defibrillation, with the goal being the delivery of the first shock within 3 minutes of collapse (Link, et al., 2010).

Intra-Arrest and Post

_–

Cardiac Arrest Care

During the arrest, and underthe direction of a team leader, the code team works to stabilize the patient by continuing high-quality CPR, performing defibrillation for pVT/VF, obtaining vascular access and giv-ing medications, performgiv-ing advanced airway management procedures when warranted, and providgiv-ing

BOX 1.1

_{Rapid Response System Calling Criteria}

• Abnormalor worseningrespiratorysymptoms • Acute change in mental status

• Chest pain or discomfort unrelieved by

nitroglycerin

• Heart rate greater than 140 beats/minute or

less than 40 beats/minute

• Oxygen saturation less than 90% despite

supplemental oxygen

• Progressive lethargy

• Staff concern about the patient’s condition • Systolic blood pressure greater than 180 mm

Hg or less than 90 mm Hg

• Threatened airway

• Urine output less than 50 mL over 4 hours • Ventilatory rate greater than 28 breaths/

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ventilation support, among other interventions. If a return of spontaneous circulation (ROSC) is achieved, post – cardiac arrest care, including advanced monitoring and targeted temperature manage-ment, is provided by a multidisciplinary team in an ICU. Post – cardiac arrest care is discussed in more detail in Chapter 4. After the resuscitation, a debriefing of the resuscitation team is recommended to discuss areas such as psychomotor skill issues, cognitive issues, team issues, family emotional issues, and professional staff emotional issues (Kronick, et al., 2015).

CARDIOPULMONARY RESUSCITATION

[Objective 8]

When an adult develops VF and suddenly collapses, his or her lungs, pulmonary veins, left heart, aorta, and arteries contain oxygenated blood (Ewy, 2005; Meursing, et al., 2005). After recognizing that CPR is indicated, chest compressions should be the initial action performed (instead of opening the airway or giving ventilations) when starting CPR in victims of sudden cardiac arrest. Performing chest compres-sions before ventilations enables better delivery of the oxygen that is already present in the lungs and arterial circulation to the heart and brain (Kern & Mostafizi, 2009).

Physiology of Chest Compressions

[Objective 8]

During CPR, myocardial blood flow is dependent on coronary perfusion pressure, which is generated when performing chest compressions. Coronary perfusion pressure is a key determinant of the success

of resuscitation, and adequate cerebral and coronary perfusion pressures are critical to neurologically nor-mal survival (Ewy, 2005). During the low-flow phase of cardiac arrest, the only source of coronary and cerebral perfusion pressures comes from the BP generated by high-quality chest compressions ( Berg, et al., 2010). High-quality chest compressions require compressing the chest at an adequate rate and depth, allowing full chest recoil after each compression (enabling the heart to refill with blood), mini-mizing interruptions in chest compressions, and avoiding excessive ventilation (Kleinman, et al., 2015). Cardiac output is the product of stroke volume and heart rate. During CPR, the force of compressions is a major determinant of stroke volume and the rate of compressions is the determinant of heart rate (Berg, et al., 2010). Current resuscitation guidelines recommend a compression rate for adults of 100 to 120 per minute (Kleinman, et al., 2015). Because stroke volume also depends on preload, an adequate blood volume is necessary for adequate perfusion. An adequate perfusion pressure cannot be obtained if the patient ’s blood volume is low, such as that caused by blood loss or significant venous dilation (eg,

hypovolemic shock, septic shock). These patients may require additional intravascular fluid volume to generate an adequate stroke volume with chest compressions (Berg, et al., 2010).

During the compression (systolic) phase of chest compression, it is essential that the compressions delivered be of sufficient depth to deliver adequate stroke volume and cerebral perfusion pressure (Benner, et al., 2011). Current resuscitation guidelines recommend a compression depth for adults of at least 2 inches (5 cm), not to exceed 2.4 inches (6 cm) (Kleinman, et al., 2015). During the release (diastolic) phase of chest compression, intrathoracic pressure is low. This helps increase the return of venous blood into the chest. If intrathoracic pressure is too high, venous return is inhibited.

ACLS Pearl

Hyperventilation is a common cause of excessive intrathoracic pressure during CPR. It is important to ventilate a patient in cardiac arrest at an age-appropriate rate and with just enough volume to see the patient’s chest rise gently. Ventilating a cardiac arrest patient too fast or with too much volume

results in excessive intrathoracic pressure, which results in decreased venous return into the chest, decreased coronary and cerebral perfusion pressures, diminished cardiac output, and decreased rates of survival.

Barriers to Effective Cardiopulmonary Resuscitation

[Objective 9]

Numerous studies have shown that the quality of CPR during actual resuscitation often falls short of established resuscitation guidelines in both out-of-hospital and in-hospital settings. Possible factors

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influencing these deficiencies include infrequent training, lack of awareness of the quality of CPR during resuscitation, and inadequate team leadership during resuscitation efforts ( Abella, et al., 2014).

Rescuer fatigue has been identified as an important potential contributor to poor CPR quality (Brooks, et al., 2014). Rescuer fatigue contributes to an inadequate depth of compressions, compromises coronary perfusion pressure, and also leads to inadequate chest recoil ( Reynolds, et al., 2012). Research has shown that the depth of compressions is compromised after just 1 minute of performing CPR (Hightower, et al., 1995; Zhang, et al., 2013) and rescuers tend not to recognize their own fatigue until after approximately 5 minutes of CPR (Reynolds, et al., 2012). To minimize fatigue, rescuers delivering chest compressions should rotate every 2 minutes. Ideally, the switch should be accomplished in less than 5 seconds and should be done while another intervention is being performed (eg, defibrillation).

The brain and heart are sensitive to ischemic injury. Because it takes time to build up cerebral and coronary perfusion pressures, even short pauses (4 to 5 seconds) in chest compressions have resulted in a dramatic drop-off in cerebral and coronary perfusion pressures, thereby reducing blood flow to the brain and heart (Ewy, 2005; Wik, et al., 2005). When chest compressions are stopped during cardiac arrest, no blood flow is generated. Even after compressions are resumed, several chest compressions are needed to restore coronary perfusion pressure.

ACLS Pearl

When caring for a patient in cardiac arrest it is essential _{that interruptions in chest compressions for}

cardiac rhythm analysis, vascular access, airway management, and other interventions be kept to a minimum. For example, charging the defibrillator before the end of a compression cycle in anticipa-tion of delivering a shock is one technique that is often used to minimize compression interrupanticipa-tions.

It is important to allow the chest wall to rebound to its normal position after each compression. Incom-plete chest wall recoil is common when performing CPR, particularly when rescuers are fatigued, and can occur when a rescuer leans over the patient ’s chest (Meaney, et al., 2013). Incomplete recoil results in

higher intrathoracic pressure, decreased coronary perfusion pressure, decreased myocardial blood flow, decreased cerebral perfusion, and decreased cardiac output (Rajab, et al., 2011; Reynolds, et al., 2012).

Feedback during Cardiopulmonary Resuscitation

[Objectives 10, 11]

Feedback devices provide voice or visual cues about the quality of CPR that are measured and reported by a defibrillator, a handheld device, or alternative technology (Morrison, et al., 2013). For example, a metronome can be used to guide the rate and rhythm of chest compressions using auditory or visual prompting at regular intervals. Timing lights may be used to prompt or time ventilations.

Some feedback devices enable information about CPR quality (eg, chest compression rate, depth, chest wall recoil) to be fed back to the rescuer using a sternal force detector or accelerometer (or both) through an

external device placed between the rescuer ’s hands and the patient ’s sternum (Sutton, et al., 2012). With

some feedback-enabled defibrillators, audible voiceprompts and visual messages on the monitor screen are triggered when measured chest compressions or ventilations are interrupted or when they deviate from preprogrammed resuscitation guideline parameters (Fig. 1.5). It is important that the chest compressor have an unobstructed view of the monitor screen throughout a resuscitation effort to enhance the effec-tiveness of audiovisual feedback (Bobrow, et al., 2013). Some defibrillators also possess technology that filters CPR artifact, allowing the rescuer to analyze a patient ’s cardiac rhythm without interrupting CPR

(Fig. 1.6). Although studies to date have not demonstrated a significant improvement in favorable neurologic outcome or survival to hospital discharge with the use of CPR feedback devices during actual cardiac arrest events, current resuscitation guidelines reflect that it may be reasonable to use audiovisual feedback devices during CPR for real-time optimization of CPR performance ( Kleinman, et al., 2015). For intubated patients, continuous EtCO2 monitoring should be used to monitor the quality of

com-pressions during resuscitation efforts. When ventilation is constant, EtCO2 reflects lung perfusion and

therefore cardiac output (McGlinch & White, 2009). EtCO2 falls sharply with the onset of cardiac

arrest, increases when effective CPR is delivered (generally 10 to 20 millimeters of mercury [mm Hg]), and returns to physiologic levels (35 to 40 mm Hg) with the ROSC ( Abella, et al., 2014). Low EtCO2 values (ie, less than 10 mm Hg) during resuscitation efforts indicate the need to explore

factors that are hindering effective CPR (eg, rescuer fatigue, cardiac tamponade, pneumothorax, bron-chospasm, mucus plugging of the endotracheal tube (ETT), kinking of the ETT, alveolar fluid in the

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ETT, an airway with an air leak, hyperventilation) (Kodali & Urman, 2014; Link, et al., 2015). As the rescuer performing chest compressions tires, a gradual decrease in waveform height can be observed on the monitor screen, indicating the need to change rescuer positions. A sudden sustained increase in EtCO2 during CPR is an indicator of ROSC. In addition to improving the quality of CPR delivered,

EtCO2 monitoring allows clinicians to perform chest compressions without pausing for pulse checks

unless a sudden increase in EtCO2 is observed, at which time ROSC can be verified (Cunningham,

et al., 2012). When feasible, additional physiologic parameters that may be used to monitor and optimize CPR quality, guide vasopressor therapy, and detect ROSC include arterial relaxation diastolic pressure, arterial pressure monitoring, and central venous oxygen saturation (Link, et al., 2015).

Mechanical Chest Compression Devices

[Objectives 12]

The use of mechanical chest compression devices has been proposed as an alternative to manual compressions to improve compression depth, rate, and consistency. When mechanical devices are used, training should be provided to reduce the time needed for device deployment ( Brooks, et al., 2014). Training should also stress the importance of minimizing interruptions in chest compressions while

the device is in use (Morrison, et al., 2013).

Fig. 1.5 Several defibrillators, such as the MRx-QCPR shown here, are equipped with a chest compression pad that enables monitoring of the quality of chest compressions and provides corrective feedback to rescuers. (Courtesy of Philips Healthcare. All rights reserved.)

Fig. 1.6 This Zoll R Series Monitor defibrillator filters cardiopulmonary resuscitation artifact, enabling the rescuer to analyze a patient ’s cardiac rhythm without interrupting chest compressions. (Courtesy Zoll Medical Corporation, Chelmsford, MA)

12

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Several mechanical chest compression devices are available. The AutoPulse (Zoll Medical Corpora-tion, Chelmsford, MA) uses a load-distributing band that is attached to a backboard and battery-powered motor (Fig. 1.7). The band encircles the patient ’s chest and mechanically and rhythmically

shortens and lengthens to compress the chest at a rate and depth consistent with resuscitation guidelines. The LUCAS Chest Compression System (Physio-Control, Jolife AB, Redmond, WA) uses a back plate that is positioned underneath the patient as a support and a piston/suction cup to compress the patient ’s anterior chest. The LUCAS 1 is powered by compressed air from a wall outlet or cylinder

(Fig. 1.8). The LUCAS 2 is electrically powered (Fig. 1.9). A UK trial studied whether the introduction of the LUCAS 2 device into front-line emergency response vehicles would improve survival from OHCA (Perkins, et al., 2015). Results showed no evidence of improvement in 30-day survival with the LUCAS 2 compared with manual compressions. The Life-Stat, formerly the Thumper (Michigan Instruments, Grand Rapids, MI), is a gas-powered piston device that is equipped with an automatic transport ventilator (Fig. 1.10).

Current resuscitation guidelines state that although manual chest compressions remain the standard of care for the treatment of cardiac arrest, the use of mechanical chest compression devices may be a reasonable alternative for use by properly trained personnel and “may be considered in specific settings

where the delivery of high-quality manual compressions may be challenging or dangerous for the pro- vider (eg, limited rescuers available, prolonged CPR, during hypothermic cardiac arrest, in a moving

ambulance, in the angiography suite, during preparation for extracorporeal CPR), provided that rescuers strictly limit interruptions in CPR during deployment and removal of the devices” (Brooks, et al., 2015).

Fig. 1.7 The AutoPulse uses a load-distributing band to compress the chest at a rate and depth consistent with resuscitation guidelines. (Courtesy Zoll Medical Corporation, Chelmsford, MA)

Fig. 1.8 The LUCAS®1 Chest Compression System is powered by compressed air from a wall outlet or cylinder. (Courtesy Physio-Control, Inc., Redmond, WA; Jolife AB, Lund, Sweden)

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PATIENT ASSESSMENT

[Objectives 13]

Patient assessment is a systematic method of evaluating a patient ’s condition and is the foundation of

med-ical care. The information obtained by the clinician when performing a patient assessment helps guide treatment decisions. Recognizing when a patient ’s condition becomes unstable requires good patient

assessment skills and is essential for improved patient outcomes.

Before approaching the patient, make sure that the scene is safe. Note any hazards or potential hazards and any visible mechanism of injury or illness. Always use appropriate personal protective equipment.

Once you come into view of the patient, immediately begin to form a general impression, which is an“across-the-room” or “from-the-doorway ” assessment of the severity of the patient ’s condition. Your

general impression should focus on three main areas that can be remembered by the mnemonic ABC: A ppearance, (work of) Breathing, and Circulation. As you finish forming your general impression, you will have a good idea if the patient is sick (unstable) or not sick (stable).

Fig. 1.9 The LUCAS®2 Chest Compression System is electrically powered. (Courtesy Physio-Control, Inc., Redmond, WA; Jolife AB, Lund, Sweden)

Fig. 1.10 The Life-Stat is a gas-powered piston device that is equipped with an automatic transport ventilator. (Courtesy Michigan Instruments, Grand Rapids, MI)

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• Appearance. The patient ’s appearance reflects the adequacy of oxygenation, ventilation, and

central nervous system function. When forming a general impression, normal findings include a patient who is aware of your approach and has normal muscle tone and equal movement of all extremities.

• Breathing. Breathing reflects the adequacy of the patient ’s oxygenation and ventilation. Normal

find-ings include breathing without excessive respiratory muscle effort that is quiet and regular with equal rise and fall of the chest. Abnormal findings include use of accessory muscles to breathe, the presence of retractions, and audible respiratory sounds that can be heard without a stethoscope such as stridor, gasping, wheezing, snoring, or gurgling.

• Circulation. Circulation reflects the adequacy of cardiac output and perfusion of vital organs. When

forming a general impression, circulation refers to skin color. Skin color normally is some shade of pink. Even patients who have heavy pigmentation have an underlying pink color to the skin. Abnor-mal findings include pallor, mottling, and cyanosis.

An abnormal finding that is observed when assessing any of these areas suggests that the patient is sick (unstable); move quickly and proceed immediately to the primary survey. If the patient ’s condition does

not appear to be urgent, proceed systematically starting with the primary survey and then the secondary survey.

Primary Survey

[Objectives 14]

The primary survey is a rapid hands-on patient assessment that focuses on basic life support interventions and management. The purposes of the primary survey are to detect the presence of life-threatening prob-lems and to immediately correct them. During this phase of patient assessment, assessment and man-agement occur at the same time.

The ABCDE sequence of the primary survey is taught to physicians, nurses, and prehospital person-nel in many types of educational courses. In programs other than cardiac-related courses, the primary survey sequence stands for A irway, Breathing, Circulation, Disability (referring to a brief neurologic exam), and E xposure. In cardiac-related courses, the “D” also stands for Defibrillation.

Repeat the primary survey:

• With any sudden change in the patient ’s condition • When interventions do not appear to be working • When vital signs are unstable

• Before any procedures are performed

• When a change in rhythm is observed on the cardiac monitor

Begin the primary survey by assessing responsiveness. Start by asking,“ Are you all right?”or “Can you

hear me?” If there is no response, then gently tap or squeeze the victim’s shoulder while repeating verbal

cues. Look at the chest for movement for 5 to 10 seconds. Call for help and ask someone to get an AED or defibrillator.

ACLS Pearl

Use the AVPU acronym when evaluating level of responsiveness:

• A ¼ A lert

• V ¼Responds to v erbal stimuli

• P¼Responds to painful stimuli

• U¼Unresponsive

Responsive Patient

Ask the patient questions to determine his or her level of responsiveness and the adequacy of his or her airway and breathing.

Airway

If the airway is not clear, clear it with suctioning or positioning as indicated. If the airway is open, move on and assess the patient ’s breathing.