Part 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

HomeCirculationVol. 142, No. 16_suppl_2Part 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyRedditDiggEmail Jump toFree AccessResearch ArticlePDF/EPUBPart 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Ashish R. Panchal, MD, PhD, Chair, Jason A. Bartos, MD, PhD, José G. Cabañas, MD, MPH, Michael W. Donnino, MD, Ian R. Drennan, ACP, PhD(C), Karen G. Hirsch, MD, Peter J. Kudenchuk, MD, Michael C. Kurz, MD, MS, Eric J. Lavonas, MD, MS, Peter T. Morley, MBBS, Brian J. O’Neil, MD, Mary Ann Peberdy, MD, Jon C. Rittenberger, MD, MS, Amber J. Rodriguez, PhD, Kelly N. Sawyer, MD, MS and Katherine M. Berg, MD, Vice Chair Ashish R. PanchalAshish R. Panchal , Jason A. BartosJason A. Bartos , José G. CabañasJosé G. Cabañas , Michael W. DonninoMichael W. Donnino , Ian R. DrennanIan R. Drennan , Karen G. HirschKaren G. Hirsch , Peter J. KudenchukPeter J. Kudenchuk , Michael C. KurzMichael C. Kurz , Eric J. LavonasEric J. Lavonas , Peter T. MorleyPeter T. Morley , Brian J. O’NeilBrian J. O’Neil , Mary Ann PeberdyMary Ann Peberdy , Jon C. RittenbergerJon C. Rittenberger , Amber J. RodriguezAmber J. Rodriguez , Kelly N. SawyerKelly N. Sawyer and Katherine M. BergKatherine M. Berg and On behalf of the Adult Basic and Advanced Life Support Writing Group Originally published21 Oct 2020https://doi.org/10.1161/CIR.0000000000000916Circulation. 2020;142:S366–S468Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: October 21, 2020: Previous Version of Record Top 10 Take-Home Messages for Adult Cardiovascular Life SupportOn recognition of a cardiac arrest event, a layperson should simultaneously and promptly activate the emergency response system and initiate cardiopulmonary resuscitation (CPR).Performance of high-quality CPR includes adequate compression depth and rate while minimizing pauses in compressions,Early defibrillation with concurrent high-quality CPR is critical to survival when sudden cardiac arrest is caused by ventricular fibrillation or pulseless ventricular tachycardia.Administration of epinephrine with concurrent high-quality CPR improves survival, particularly in patients with nonshockable rhythms.Recognition that all cardiac arrest events are not identical is critical for optimal patient outcome, and specialized management is necessary for many conditions (eg, electrolyte abnormalities, pregnancy, after cardiac surgery).The opioid epidemic has resulted in an increase in opioid-associated out-of-hospital cardiac arrest, with the mainstay of care remaining the activation of the emergency response systems and performance of high-quality CPR.Post–cardiac arrest care is a critical component of the Chain of Survival and demands a comprehensive, structured, multidisciplinary system that requires consistent implementation for optimal patient outcomes.Prompt initiation of targeted temperature management is necessary for all patients who do not follow commands after return of spontaneous circulation to ensure optimal functional and neurological outcome.Accurate neurological prognostication in brain-injured cardiac arrest survivors is critically important to ensure that patients with significant potential for recovery are not destined for certain poor outcomes due to care withdrawal.Recovery expectations and survivorship plans that address treatment, surveillance, and rehabilitation need to be provided to cardiac arrest survivors and their caregivers at hospital discharge to optimize transitions of care to home and to the outpatient setting.PreambleIn 2015, approximately 350 000 adults in the United States experienced nontraumatic out-of-hospital cardiac arrest (OHCA) attended by emergency medical services (EMS) personnel.1 Approximately 10.4% of patients with OHCA survive their initial hospitalization, and 8.2% survive with good functional status. The key drivers of successful resuscitation from OHCA are lay rescuer cardiopulmonary resuscitation (CPR) and public use of an automated external defibrillator (AED). Despite recent gains, only 39.2% of adults receive layperson-initiated CPR, and the general public applied an AED in only 11.9% of cases.1 Survival rates from OHCA vary dramatically between US regions and EMS agencies.2,3 After significant improvements, survival from OHCA has plateaued since 2012.Approximately 1.2% of adults admitted to US hospitals suffer in-hospital cardiac arrest (IHCA).1 Of these patients, 25.8% were discharged from the hospital alive, and 82% of survivors have good functional status at the time of discharge. Despite steady improvement in the rate of survival from IHCA, much opportunity remains.The International Liaison Committee on Resuscitation (ILCOR) Formula for Survival emphasizes 3 essential components for good resuscitation outcomes: guidelines based on sound resuscitation science, effective education of the lay public and resuscitation providers, and implementation of a well-functioning Chain of Survival.4These guidelines contain recommendations for basic life support (BLS) and advanced life support (ALS) for adult patients and are based on the best available resuscitation science. The Chain of Survival, introduced in Major Concepts, is now expanded to emphasize the important component of survivorship during recovery from cardiac arrest, requires coordinated efforts from medical professionals in a variety of disciplines and, in the case of OHCA, from lay rescuers, emergency dispatchers, and first responders. In addition, specific recommendations about the training of resuscitation providers are provided in “Part 6: Resuscitation Education Science,” and recommendations about systems of care are provided in “Part 7: Systems of Care.”IntroductionScope of the GuidelinesThese guidelines are designed primarily for North American healthcare providers who are looking for an up-to-date summary for BLS and ALS for adults as well as for those who are seeking more in-depth information on resuscitation science and gaps in current knowledge. The BLS care of adolescents follows adult guidelines. This Part of the 2020 American Heart Association (AHA) Guidelines for CPR and Emergency Cardiovascular Care includes recommendations for clinical care of adults with cardiac arrest, including those with life-threatening conditions in whom cardiac arrest is imminent, and after successful resuscitation from cardiac arrest.Some recommendations are directly relevant to lay rescuers who may or may not have received CPR training and who have little or no access to resuscitation equipment. Other recommendations are relevant to persons with more advanced resuscitation training, functioning either with or without access to resuscitation drugs and devices, working either within or outside of a hospital. Some treatment recommendations involve medical care and decision-making after return of spontaneous circulation (ROSC) or when resuscitation has been unsuccessful. Importantly, recommendations are provided related to team debriefing and systematic feedback to increase future resuscitation success.Organization of the Writing GroupThe Adult Cardiovascular Life Support Writing Group included a diverse group of experts with backgrounds in emergency medicine, critical care, cardiology, toxicology, neurology, EMS, education, research, and public health, along with content experts, AHA staff, and the AHA senior science editors. Each recommendation was developed and formally approved by the writing group.The AHA has rigorous conflict of interest policies and procedures to minimize the risk of bias or improper influence during the development of guidelines. Before appointment, writing group members disclosed all commercial relationships and other potential (including intellectual) conflicts. These procedures are described more fully in “Part 2: Evidence Evaluation and Guidelines Development.” Disclosure information for writing group members is listed in Appendix 1.Methodology and Evidence ReviewThese guidelines are based on the extensive evidence evaluation performed in conjunction with the ILCOR and affiliated ILCOR member councils. Three different types of evidence reviews (systematic reviews, scoping reviews, and evidence updates) were used in the 2020 process. Each of these resulted in a description of the literature that facilitated guideline development. A more comprehensive description of these methods is provided in “Part 2: Evidence Evaluation and Guidelines Development.”Class of Recommendation and Level of EvidenceAs with all AHA guidelines, each 2020 recommendation is assigned a Class of Recommendation (COR) based on the strength and consistency of the evidence, alternative treatment options, and the impact on patients and society (Table 1). The Level of Evidence (LOE) is based on the quality, quantity, relevance, and consistency of the available evidence. For each recommendation, the writing group discussed and approved specific recommendation wording and the COR and LOE assignments. In determining the COR, the writing group considered the LOE and other factors, including systems issues, economic factors, and ethical factors such as equity, acceptability, and feasibility. These evidence-review methods, including specific criteria used to determine COR and LOE, are described more fully in “Part 2: Evidence Evaluation and Guidelines Development.” The Adult Basic and Advanced Life Support Writing Group members had final authority over and formally approved these recommendations.Table 1. Applying Class of Recommendation and Level of Evidence to Clinical Strategies, Interventions, Treatments, or Diagnostic Testing in Patient Care (Updated May 2019)*This table defines the Classes of Recommendation (COR) and Levels of Evidence (LOE). COR indicates the strength the writing group assigns the recommendation, and the LOE is assigned based on the quality of the scientific evidence. The outcome or result of the intervention should be specified (an improved clinical outcome or increased diagnostic accuracy or incremental prognostic information).Classes of RecommendationCOR designations include Class 1, a strong recommendation for which the potential benefit greatly outweighs the risk; Class 2a, a moderate recommendation for which benefit most likely outweighs the risk; Class 2b, a weak recommendation for which it’s unknown whether benefit will outweigh the risk; Class 3: No Benefit, a moderate recommendation signifying that there is equal likelihood of benefit and risk; and Class 3: Harm, a strong recommendation for which the risk outweighs the potential benefit.Suggested phrases for writing Class 1 recommendations includeIs recommendedIs indicated/useful/effective/beneficialShould be performed/administered/otherComparative-effectiveness phrases include treatment/strategy A is recommended/indicated in preference to treatment B, and treatment A should be chosen over treatment B.Suggested phrases for writing Class 2a recommendations includeIs reasonableCan be useful/effective/beneficialComparative-effectiveness phrases include treatment/strategy A is probably recommended/indicated in preference to treatment B, and it is reasonable to choose treatment A over treatment B.For comparative-effectiveness recommendations (COR 1 and 2a; LOE A and B only), studies that support the use of comparator verbs should involve direct comparisons of the treatments or strategies being evaluated.Suggested phrases for writing Class 2b recommendations includeMay/might be reasonableMay/might be consideredUsefulness/effectiveness is unknown/unclear/uncertain or not well-establishedSuggested phrases for writing Class 3: No Benefit recommendations (generally, LOE A or B use only) includeIs not recommendedIs not indicated/useful/effective/beneficialShould not be performed/administered/otherSuggested phrases for writing Class 3: Harm recommendations includePotentially harmfulCauses harmAssociated with excess morbidity/mortalityShould not be performed/administered/otherLevels of EvidenceFor LOEs, the method of assessing quality is evolving, including the application of standardized, widely-used, and preferably validated evidence grading tools; and for systematic reviews, the incorporation of an Evidence Review Committee. LOE designations include Level A, Level B-R, Level B-NR, Level C-LD, and Level C-EO.Those categorized as Level A are derived fromHigh-quality evidence from more than 1 randomized clinical trial, or RCTMeta-analyses of high-quality RCTsOne or more RCTs corroborated by high-quality registry studiesThose categorized as Level B-R (randomized) are derived fromModerate-quality evidence from 1 or more RCTsMeta-analyses of moderate-quality RCTsThose categorized as Level B-NR (nonrandomized) are derived fromModerate-quality evidence from 1 or more well-designed, well-executed nonrandomized studies, observational studies, or registry studiesMeta-analyses of such studiesThose categorized as Level C-LD (limited data) are derived fromRandomized or nonrandomized observational or registry studies with limitations of design or executionMeta-analyses of such studiesPhysiological or mechanistic studies in human subjectsThose categorized as Level C-EO (expert opinion) are derived fromConsensus of expert opinion based on clinical experienceCOR and LOE are determined independently (any COR may be paired with any LOE).A recommendation with LOE C does not imply that the recommendation is weak. Many important clinical questions addressed in guidelines do not lend themselves to clinical trials. Although RCTs are unavailable, there may be a very clear clinical consensus that a particular test or therapy is useful or effective.Table 1. Applying Class of Recommendation and Level of Evidence to Clinical Strategies, Interventions, Treatments, or Diagnostic Testing in Patient Care (Updated May 2019)*Unfortunately, despite improvements in the design and funding support for resuscitation research, the overall certainty of the evidence base for resuscitation science is low. Of the 250 recommendations in these guidelines, only 2 recommendations are supported by Level A evidence (high-quality evidence from more than 1 randomized controlled trial [RCT], or 1 or more RCT corroborated by high-quality registry studies.) Thirty-seven recommendations are supported by Level B-Randomized Evidence (moderate evidence from 1 or more RCTs) and 57 by Level B-Nonrandomized evidence. The majority of recommendations are based on Level C evidence, including those based on limited data (123 recommendations) and expert opinion (31 recommendations). Accordingly, the strength of recommendations is weaker than optimal: 78 Class 1 (strong) recommendations, 57 Class 2a (moderate) recommendations, and 89 Class 2b (weak) recommendations are included in these guidelines. In addition, 15 recommendations are designated Class 3: No Benefit, and 11 recommendations are Class 3: Harm. Clinical trials in resuscitation are sorely needed.Guideline StructureThe 2020 Guidelines are organized into knowledge chunks, grouped into discrete modules of information on specific topics or management issues.5 Each modular knowledge chunk includes a table of recommendations that uses standard AHA nomenclature of COR and LOE. A brief introduction or short synopsis is provided to put the recommendations into context with important background information and overarching management or treatment concepts. Recommendation-specific text clarifies the rationale and key study data supporting the recommendations. When appropriate, flow diagrams or additional tables are included. Hyperlinked references are provided to facilitate quick access and review.Document Review and ApprovalEach of the 2020 Guidelines documents was submitted for blinded peer review to 5 subject-matter experts nominated by the AHA. Before appointment, all peer reviewers were required to disclose relationships with industry and any other conflicts of interest, and all disclosures were reviewed by AHA staff. Peer reviewer feedback was provided for guidelines in draft format and again in final format. All guidelines were reviewed and approved for publication by the AHA Science Advisory and Coordinating Committee and the AHA Executive Committee. Disclosure information for peer reviewers is listed in Appendix 2.References1. Virani SS, Alonso A, Benjamin EJ, Bittencourt MS, Callaway CW, Carson AP, Chamberlain AM, Chang AR, Cheng S, Delling FN, et al.; on behalf of the American Heart Association Council on Epidemiology and Prevention Statistics Committee and Stroke Statistics Subcommittee. Heart disease and stroke statistics—2020 update: a report from the American Heart Association.Circulation. 2020; 141:e139–e596. doi: 10.1161/CIR.0000000000000757LinkGoogle Scholar2. Okubo M, Schmicker RH, Wallace DJ, Idris AH, Nichol G, Austin MA, Grunau B, Wittwer LK, Richmond N, Morrison LJ, Kurz MC, Cheskes S, Kudenchuk PJ, Zive DM, Aufderheide TP, Wang HE, Herren H, Vaillancourt C, Davis DP, Vilke GM, Scheuermeyer FX, Weisfeldt ML, Elmer J, Colella R, Callaway CWResuscitation Outcomes Consortium Investigators. Variation in Survival After Out-of-Hospital Cardiac Arrest Between Emergency Medical Services Agencies.JAMA Cardiol. 2018; 3:989–999. doi: 10.1001/jamacardio.2018.3037CrossrefMedlineGoogle Scholar3. Zive DM, Schmicker R, Daya M, Kudenchuk P, Nichol G, Rittenberger JC, Aufderheide T, Vilke GM, Christenson J, Buick JE, Kaila K, May S, Rea T, Morrison LJROC Investigators. Survival and variability over time from out of hospital cardiac arrest across large geographically diverse communities participating in the Resuscitation Outcomes Consortium.Resuscitation. 2018; 131:74–82. doi: 10.1016/j.resuscitation.2018.07.023CrossrefMedlineGoogle Scholar4. Søreide E, Morrison L, Hillman K, Monsieurs K, Sunde K, Zideman D, Eisenberg M, Sterz F, Nadkarni VM, Soar J, Nolan JPUtstein Formula for Survival Collaborators. The formula for survival in resuscitation.Resuscitation. 2013; 84:1487–1493. doi: 10.1016/j.resuscitation.2013.07.020CrossrefMedlineGoogle Scholar5. Levine GN, O’Gara PT, Beckman JA, Al-Khatib SM, Birtcher KK, Cigarroa JE, de Las Fuentes L, Deswal A, Fleisher LA, Gentile F, Goldberger ZD, Hlatky MA, Joglar JA, Piano MR, Wijeysundera DN. Recent Innovations, Modifications, and Evolution of ACC/AHA Clinical Practice Guidelines: An Update for Our Constituencies: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines.Circulation. 2019; 139:e879–e886. doi: 10.1161/CIR.0000000000000651LinkGoogle ScholarAbbreviationsACDactive compression-decompressionACLSadvanced cardiovascular life supportADCapparent diffusion coefficientAEDautomated external defibrillatorAHAAmerican Heart AssociationALSadvanced life supportaORadjusted odds ratioAVatrioventricularBLSbasic life supportCORClass of RecommendationCoSTRInternational Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment RecommendationsCPRcardiopulmonary resuscitationCTcomputed tomographyDWIdiffusion-weighted imagingECGelectrocardiogramECPRextracorporeal cardiopulmonary resuscitationEEGelectroencephalogramEMSemergency medical servicesETCO2(partial pressure of) end-tidal carbon dioxideETIendotracheal intubationGWRgray-white ratioICUintensive care unitIHCAin-hospital cardiac arrestILCORInternational Liaison Committee on ResuscitationIOintraosseousITDimpedance threshold deviceIVintravenousLASTlocal anesthetic systemic toxicityLOELevel of EvidenceMAPmean arterial pressureMRImagnetic resonance imagingNSEneuron-specific enolaseOHCAout-of-hospital cardiac arrestPaco2arterial partial pressure of carbon dioxidePCIpercutaneous coronary interventionPEpulmonary embolismPMCDperimortem cesarean deliverypVTpulseless ventricular tachycardiaRCTrandomized controlled trialROSCreturn of spontaneous circulationS100BS100 calcium binding proteinSGAsupraglottic airwaySSEPsomatosensory evoked potentialSTEMIST-segment elevation myocardial infarctionSVTsupraventricular tachycardiaTCAtricyclic antidepressantTORtermination of resuscitationTTMtargeted temperature managementVFventricular fibrillationVTventricular tachycardiaMajor ConceptsOverview Concepts of Adult Cardiac ArrestSurvival and recovery from adult cardiac arrest depend on a complex system working together to secure the best outcome for the victim. The main focus in adult cardiac arrest events includes rapid recognition, prompt provision of CPR, defibrillation of malignant shockable rhythms, and post-ROSC supportive care and treatment of underlying causes. This approach recognizes that most sudden cardiac arrest in adults is of cardiac cause, particularly myocardial infarction and electric disturbances. Arrests without a primary cardiac origin (eg, from respiratory failure, toxic ingestion, pulmonary embolism [PE], or drowning) are also common, however, and in such cases, treatment for reversible underlying causes is important for the rescuer to consider.1 Some noncardiac etiologies may be particularly common in the in-hospital setting. Others, such as opioid overdose, are sharply on the rise in the out-of-hospital setting.2 For any cardiac arrest, rescuers are instructed to call for help, perform CPR to restore coronary and cerebral blood flow, and apply an AED to directly treat ventricular fibrillation (VF) or ventricular tachycardia (VT), if present. Although the majority of resuscitation success is achieved by provision of high-quality CPR and defibrillation, other specific treatments for likely underlying causes may be helpful in some cases.Adult Chain of SurvivalThe primary focus of cardiac arrest management for providers is the optimization of all critical steps required to improve outcomes. These include activation of the emergency response, provision of high-quality CPR and early defibrillation, ALS interventions, effective post-ROSC care including careful prognostication, and support during recovery and survivorship. All of these activities require organizational infrastructures to support the education, training, equipment, supplies, and communication that enable each survival. Thus, we recognize that each of these diverse aspects of care contributes to the ultimate functional survival of the cardiac arrest victim.Resuscitation causes, processes, and outcomes are very different for OHCA and IHCA, which are reflected in their respective Chains of Survival (Figure 1). In OHCA, the care of the victim depends on community engagement and response. It is critical for community members to recognize cardiac arrest, phone 9-1-1 (or the local emergency response number), perform CPR (including, for untrained lay rescuers, compression-only CPR), and use an AED.3,4 Emergency medical personnel are then called to the scene, continue resuscitation, and transport the patient for stabilization and definitive management. In comparison, surveillance and prevention are critical aspects of IHCA. When an arrest occurs in the hospital, a strong multidisciplinary approach includes teams of medical professionals who respond, provide CPR, promptly defibrillate, begin ALS measures, and continue post-ROSC care. Outcomes from IHCA are overall superior to those from OHCA,5 likely because of reduced delays in initiation of effective resuscitation.Download figureDownload PowerPointFigure 1. 2020 American Heart Association Chains of Survival for IHCA and OHCA. CPR indicates cardiopulmonary resuscitation; IHCA, in-hospital cardiac arrest; and OHCA, out-of-hospital cardiac arrest.The Adult OHCA and IHCA Chains of Survival have been updated to better highlight the evolution of systems of care and the critical role of recovery and survivorship with the addition of a new link. This Recovery link highlights the enormous recovery and survivorship journey, from the end of acute treatment for critical illness through multimodal rehabilitation (both short- and long-term), for both survivors and families after cardiac arrest. This new link acknowledges the need for the system of care to support recovery, discuss expectations, and provide plans that address treatment, surveillance, and rehabilitation for cardiac arrest survivors and their caregivers as they transition care from the hospital to home and return to role and social function.References1. Lavonas EJ, Drennan IR, Gabrielli A, Heffner AC, Hoyte CO, Orkin AM, Sawyer KN, Donnino MW. Part 10: special circumstances of resuscitation: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.Circulation. 2015; 132(suppl 2):S501–S518. doi: 10.1161/CIR.0000000000000264LinkGoogle Scholar2. Dezfulian C, Orkin AM, Maron BA, Elmer J, Girota S, Gladwin MT, Merchant RM, Panchal AR, Perman SM, Starks M, van Diepen S, Lavonas EJon behalf of the American Heart Association Council on Cardiopulmonary, Critical Care, Perioperative and Resuscitation; Council on Arteriosclerosis, Thrombosis and Vascular Biology; Council on Cardiovascular and Stroke Nursing; and Council on Clinical Cardiology. Opioid-associated out-of-hospital cardiac arrest: distinctive clinical features and implications for healthcare and public responses: a scientific statement from the American Heart Association.Circulation. In press.Google Scholar3. Sayre MR, Berg RA, Cave DM, Page RL, Potts J, White RDAmerican Heart Association Emergency Cardiovascular Care Committee. Hands-only (compression-only) cardiopulmonary resuscitation: a call to action for bystander response to adults who experience out-of-hospital sudden cardiac arrest: a science advisory for the public from the American Heart Association Emergency Cardiovascular Care Committee.Circulation. 2008; 117:2162–2167. doi: 10.1161/CIRCULATIONAHA.107.189380LinkGoogle Scholar4. Kleinman ME, Brennan EE, Goldberger ZD, Swor RA, Terry M, Bobrow BJ, Gazmuri RJ, Travers AH, Rea T. Part 5: adult basic life support and cardiopulmonary resuscitation quality: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.Circulation. 2015; 132(suppl 2):S414–S435. doi: 10.1161/CIR.0000000000000259LinkGoogle Scholar5. Virani SS, Alonso A, Benjamin EJ, Bittencourt MS, Callaway CW, Carson AP, Chamberlain AM, Chang AR, Cheng S, Delling FN, et al.; on behalf of the American Heart Association Council on Epidemiology and Prevention Statistics Committee and Stroke Statistics Subcommittee. Heart disease and stroke statistics—2020 update: a report from the American Heart Association.Circulation. 2020; 141:e139–e596. doi: 10.1161/CIR.0000000000000757LinkGoogle ScholarSequence of ResuscitationRecognition of Cardiac ArrestSynopsisLay rescuer CPR improves survival from cardiac arrest by 2- to 3-fold.1 The benefit of providing CPR to a patient in cardiac arrest outweighs any potential risk of providing chest compressions to someone who is unconscious but not in cardiac arrest. It has been shown that the risk of injury from CPR is low in these patients.2It has been shown previously that all rescuers may have difficulty detecting a pulse, leading to delays in CPR, or in some cases CPR not being performed at all for patients in cardiac arrest.3 Recognition of cardiac arrest by lay rescuers, therefore, is determined on the basis of level of consciousness and the respiratory effort of the victim. Recognition of cardiac arrest by healthcare providers includes a pulse check, but the importance of not prolonging efforts to detect a pulse is emphasized.Recommendation-Specific Supportive TextAgonal breathing is characterized by slow, irregular gasping respirations that are ineffective for ventilation. Agonal breathing is described by lay rescuers with a variety of terms including, abnormal breathing, snoring respirations, and gasping.4 Agonal breathing is common, reported as being present in up to 40% to 60% of victims of OHCA.5 The presence of agonal breathing is cited as a common reason for lay rescuers to misdiagnose a patient as not being in cardiac arrest.6 In patients who are unresponsive, with absent or abnormal breathing, lay rescuers should assume the patient is in cardiac arrest, call for help, and promptly initiate CPR. These 2 criteria (patient responsiveness and assessment of breathing) have been shown to rapidly identify a significant proportion of patients who are in cardiac arrest, allowing for immediate initiation of lay rescuer CPR. Further, initiation of chest compressions in patients who are unconscious but not in cardiac arrest is associated with low rates of significant adverse events.2 The adverse events noted included pain in the area of chest compressions (8.7%), bone fracture (ribs and clavicle) (1.7%), and rhabdomyolysis (0.3%), with no visceral injuries described.2Protracted delays in CPR can occur when checking for a pulse at the outset of resuscitation efforts as well as between successive cycles of CPR. Healthcare providers often take too long to check for a pulse7,8 and have difficulty determining if a pulse is present or absent.7–9 There is no evidence, however, that checking for breathing, coughing, or movement is superior to a pulse check for detection of circulation.10 Thus, healthcare providers are directed to quickly check for a pulse and to promptly start compressions when a pulse is not definitively palpated.9,11This topic last received formal evidence review in 2010.3References1. Sasson C, Rogers MA, Dahl J, Kellermann AL. Predictors of survival from out-of-hospital cardiac arrest: a s