Abstract
This 2020 International Consensus on Cardiopulmonary Resuscitation (CPR) and Emergency Cardiovascular Care Science With Treatment Recommendations on basic life support summarizes evidence evaluations performed for 20 topics that were prioritized by the Basic Life Support Task Force of the International Liaison Committee on Resuscitation. The evidence reviews include 16 systematic reviews, 3 scoping reviews, and 1 evidence update. Per agreement within the International Liaison Committee on Resuscitation, new or revised treatment recommendations were only made after a systematic review.
Systematic reviews were performed for the following topics: dispatch diagnosis of cardiac arrest, use of a firm surface for CPR, sequence for starting CPR (compressions-airway-breaths versus airway-breaths-compressions), CPR before calling for help, duration of CPR cycles, hand position during compressions, rhythm check timing, feedback for CPR quality, alternative techniques, public access automated external defibrillator programs, analysis of rhythm during chest compressions, CPR before defibrillation, removal of foreign-body airway obstruction, resuscitation care for suspected opioid-associated emergencies, drowning, and harm from CPR to victims not in cardiac arrest.
The topics that resulted in the most extensive task force discussions included CPR during transport, CPR before calling for help, resuscitation care for suspected opioid-associated emergencies, feedback for CPR quality, and analysis of rhythm during chest compressions. After discussion of the scoping reviews and the evidence update, the task force prioritized several topics for new systematic reviews.
Keywords
This is the fourth in a series of annual International Liaison Committee on Resuscitation (ILCOR) 2020 International Consensus on Cardiopulmonary Resuscitation (CPR) and Emergency Cardiovascular Care (ECC) Science With Treatment Recommendations (CoSTR) summary publications. This 2020 CoSTR for basic life support (BLS) includes new topics addressed by systematic reviews (SysRevs) performed within the past 12 months and prioritized by the BLS Task Force. It also includes updates of the BLS treatment recommendations published from 2010 through 2019,
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, - Soar J.
- Maconochie I.
- Wyckoff M.H.
- et al.
2019 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Pediatric Life Support; Neonatal Life Support; Education, Implementation, and Teams; and First Aid Task Forces.
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as needed, based on additional evidence evaluations. As a result, this 2020 CoSTR for BLS is the most comprehensive update since 2010.The 3 major types of evidence evaluation supporting this 2020 document are the SysRev, the scoping review (ScopRev), and the evidence update (EvUp).
The SysRev is a rigorous process, following strict methodology to answer a specific question; each of these ultimately resulted in generation of the task force consensus on science with treatment recommendations included in this document. The SysRevs were performed by a knowledge synthesis unit, an expert systematic reviewer, or the BLS Task Force, and many resulted in separate published SysRevs.
To begin the SysRev, the question to be answered was phrased in terms of the PICOST (population, intervention, comparator, outcome, study design, time frame) format. The methodology used to identify the evidence was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.
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The approach used to evaluate the evidence was based on that proposed by the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) working group.PRISMA. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) website. http://www.prisma-statement.org/. Accessed December 31, 2019.
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Using this approach, the task force rated as high, moderate, low, or very low the certainty/confidence in the estimates of effect of an intervention or assessment across a body of evidence (excluding animal studies) for each of the predefined outcomes. Randomized controlled trials (RCTs) generally began the analysis as high-certainty evidence, and observational studies generally began the analysis as low-certainty evidence; examination of the evidence using the GRADE approach could result in downgrading or upgrading of the certainty of evidence. For additional information, refer to this supplement’s “Evidence Evaluation Process and Management of Potential Conflicts of Interest.”5.2.1:study limitations. In: Schünemann H, Brozek J, Guyatt G, Oxman A, eds. GRADE Handbook; 2013. https://gdt.gradepro.org/app/handbook/handbook.html#h.m9385o5z3li7. Accessed December 31, 2019.
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When a pre-2015 treatment recommendation was not updated, the language used differs from that used in the GRADE approach because GRADE was not used before 2015.
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Draft 2020 CoSTRs for BLS were posted on the ILCOR website
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public comment between December 31, 2019, and February 16, 2020, with comments accepted through February 29, 2020. These new draft 2020 CoSTR statements for BLS received 45 694 views and 27 comments.International Liaison Committee on Resuscitation website. https://www.ilcor.org. Accessed March 3, 2020.
This summary statement contains the final wording of the CoSTR statements as approved by the ILCOR task forces and by the ILCOR member councils after review and consideration of comments posted online in response to the draft CoSTRs. Within this publication, each topic includes the PICOST as well as the CoSTR, an expanded “Justification and Evidence-to-Decision Framework Highlights” section, and a list of knowledge gaps requiring future research studies. An evidence-to-decision table is included for each CoSTR in Appendix A in the Supplementary Material of this document.
The second major type of evidence evaluation performed to support this 2020 CoSTR for BLS is a ScopRev. ScopRevs are designed to identify the extent, range, and nature of evidence on a topic or a question, and they were performed by topic experts in consultation with the BLS Task Force. The task force analyzed the identified evidence and determined its value and implications for resuscitation practice or research. The rationale for the ScopRev, the summary of evidence, and the task force insights are all highlighted in the body of this publication. The most recent treatment recommendation is included. The task force notes whether the ScopRev identified substantive evidence that may result in a change in ILCOR treatment recommendations. If sufficient evidence was identified, the task force suggested consideration of a (future) SysRev to supply sufficient detail to support the development of an updated CoSTR. All ScopRevs are included in their entirety in Appendix B in the Supplementary Material of this publication.
The third type of evidence evaluation supporting this 2020 CoSTR for BLS is an EvUp. EvUps are generally performed for topics previously reviewed by ILCOR to identify new studies published after the most recent ILCOR evidence evaluation, typically through use of search terms and methodologies from previous reviews. These EvUps were performed by task force members, collaborating experts, or members of council writing groups. The EvUps are cited in the body of this document with a note about whether the evidence suggested the need to consider a SysRev; the existing ILCOR treatment recommendation was reiterated. In this document, no change in ILCOR treatment recommendations resulted from an EvUp; if substantial new evidence was identified, the task force recommended consideration of a SysRev. All EvUps are included in Appendix AAppendix C in the Supplementary Material of this publication.
The BLS Task Force considered the availability of new evidence as well as the evidence needed to create, confirm, or revise treatment recommendations. The chapter topics are organized in sections that approximate the order of the steps of resuscitation. For each reviewed topic, the method of review (SysRev, ScopRev, EvUp) is clearly labeled, with links to the relevant review documents in the Appendix AAppendix in the Supplementary Material.
Topics Reviewed in This 2020 BLS CoSTR
Note: As indicated above, the BLS CoSTR evidence reviews were all completed in February 2020. As a result, this document does not address the topic of potential influence of coronavirus disease 2019 (COVID-19) on resuscitation practice. In the spring of 2020, an ILCOR writing group was assembled to identify and evaluate the published evidence regarding risks of aerosol generation and infection transmission during attempted resuscitation of adults, children, and infants. This group developed a consensus on science with treatment recommendations and task force insights. This statement is published as a separate document.
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As new evidence emerges, the ILCOR task forces will review and update this statement, so the reader is referred to the ILCOR website14
for the most up-to-date recommendations.International Liaison Committee on Resuscitation website. https://www.ilcor.org. Accessed March 3, 2020.
Early Access and Cardiac Arrest Prevention, Including Emergency Medical Dispatch and Dispatcher-Assisted CPR (DA-CPR)
- •Dispatch diagnosis of cardiac arrest (BLS 740: SysRev)
- •Dispatcher instructions in CPR (BLS 359: SysRev)
- •Dispatcher-assisted compression-only CPR versus conventional CPR (BLS 359: SysRev)
Compression-Only CPR
- •Lay rescuer chest compression–only versus standard CPR (BLS 547: SysRev)
- •Emergency medical services (EMS) chest compression–only compared with conventional CPR (BLS 360: SysRev)
- •In-hospital chest compression–only CPR versus conventional CPR (BLS 372: SysRev)
- •Rescuer fatigue in chest compression–only CPR (BLS 349: ScopRev)
CPR Sequence
- •Firm surface for CPR (BLS 370: SysRev)
- •Starting CPR (compressions-airway-breaths [C-A-B] versus airway-breaths-compressions [A-B-C]) (BLS 661: SysRev)
- •CPR before call for help (BLS 1527: SysRev)
- •Duration of CPR cycles (2 minutes versus other) (BLS 346: SysRev)
- •Check for circulation during BLS (BLS 348: EvUp)
Components of High-Quality CPR
- •Hand position during compressions (BLS 357: SysRev)
- •Chest compression rate, chest compression depth, and chest wall recoil (BLS 366, BLS 367, BLS 343: ScopRev)
- •Compression-to-ventilation ratio (BLS 362: SysRev)
- •Timing of rhythm check (BLS 345: SysRev)
- •Feedback for CPR quality (BLS 361: SysRev)
- •Alternative techniques (cough, precordial thump, fist pacing) (BLS 374: SysRev)
Defibrillation
- •Public access automated external defibrillator (AED) programs (BLS 347: SysRev)
- •Analysis of rhythm during chest compressions (BLS 373: SysRev)
- •CPR before defibrillation (BLS 363: SysRev)
- •Paddle size and placement for defibrillation (ALS-E-030A: ScopRev)
Special Circumstances
- •CPR during transport (BLS 1509: ScopRev)
- •Removal of foreign-body airway obstruction (FBAO) (BLS 368: SysRev)
- •Resuscitation care for suspected opioid-associated emergencies (BLS 811: SysRev)
- •Drowning (BLS 856: SysRev)
Potential Harm From CPR
- •Harm from CPR to victims not in cardiac arrest (BLS 353: SysRev)
- •Harm to rescuers from CPR (BLS 354: ScopRev)
Early Access and Cardiac Arrest Prevention, Including Emergency Medical Dispatch and DA-CPR
A variety of terms have been used to identify the person(s) at an emergency telephone call center who are charged with answering the call, interacting with the caller, and assigning the needed care providers to the incident scene (traditionally called dispatchers). Terminology is similarly varied for the process the dispatcher uses to provide real-time CPR instructions to bystanders at the scene of an out-of-hospital cardiac arrest (OHCA). To remain consistent with the ILCOR evidence review, the term DA-CPR will be used to describe such coaching in this update, recognizing that other terms (eg, telecommunicator CPR and telephone CPR) could be substituted.
Dispatch Diagnosis of Cardiac Arrest (BLS 740: SysRev)
Rationale for Review
Accurate recognition of cardiac arrest by emergency medical dispatchers at the time of the emergency call is an important early step in cardiac arrest management, enabling initiation of DA-CPR and appropriate and timely emergency response. The overall accuracy of dispatchers in recognizing cardiac arrest is not well known. Furthermore, it is not known if there are specific call characteristics that affect the ability to recognize cardiac arrest.
Population, Intervention, Comparator, Outcome, Study Design, and Time Frame
Population: Adults and children with OHCA
- •Intervention: Characteristics of the call process (these might include the specific words by the caller, language or idioms spoken by the caller and understood by the call taker, perceptions of the call receiver, emotional state of the caller, other caller characteristics, type of personnel receiving the call, background noises, etc)
- •Comparators: Absence of identified characteristics of the call process
- •Outcomes: Any diagnostic test outcomes
- •Study designs: RCTs and nonrandomized studies (non-RCTs, interrupted time series, controlled before-and-after studies, cohort studies) were eligible for inclusion. Unpublished studies (eg, conference abstracts, trial protocols) were excluded.
- •Time frame: All years and all languages were included, provided there was an English abstract. The literature search was updated November 28, 2019.
- •PROSPERO registration: CRD42019140265
Consensus on Science
A variety of algorithms and criteria (both commercial and locally developed) are used by dispatch centers to identify potential life-threatening events, such as cardiac arrest and triage emergency responders, to the scene appropriately. The dispatch centers reported great variability of overall accuracy of these algorithms and criteria for recognizing an OHCA in adults (Table 1).
Table 1Diagnostic Performance.
| Outcome | Certainty | Studies | No. of Patients | Median (IQR) |
|---|---|---|---|---|
| Sensitivity | Very low (risk of bias, imprecision, inconsistency) | 46* | 84 534† | 0.79 (0.69–0.83) |
| False-negative rate (undertriage) | Very low (risk of bias, imprecision, inconsistency) | 46* | 84 534† | 0.21 (0.17–0.32) |
| Specificity | Very low (risk of bias, inconsistency) | 12‡ | 789 004§ | 0.99 (0.93–1.00) |
| False-positive rate (overtriage) | Very low (risk of bias, inconsistency) | 12‡ | 789 004§ | 0.01 (0.01–0.07) |
| Negative predictive value | Low (risk of bias, inconsistency) | 12‡ | 789 004§ | 1.00 (0.92–1.00) |
| Positive predictive value | Low (risk of bias, inconsistency) | 12‡ | 789 004§ | 0.76 (0.50–0.85) |
| Positive likelihood ratio | Low (risk of bias, inconsistency) | 12‡ | 789 004§ | 54.72 (11.28–152.22) |
| Negative likelihood ratio | Low (risk of bias, inconsistency) | 12‡ | 789 004§ | 0.22 (0.19–0.24) |
IQR indicates interquartile range; and OHCA, out-of-hospital cardiac arrest.
Sensitivity = proportion of confirmed cardiac arrest patients labeled as cardiac arrest by the dispatcher. False-negative rate = proportion of confirmed cardiac arrest patients who are not labeled as cardiac arrest by the dispatcher. Specificity = proportion of patients without confirmed cardiac arrest identified who are not labeled as cardiac arrest by dispatchers. False-positive rate = proportion of patients without cardiac arrest who are incorrectly labeled as cardiac arrest by the dispatcher. Negative predictive value = the proportion of patients labeled as not cardiac arrest by the dispatcher who are found not to have confirmed cardiac arrest. Positive predictive value = the proportion of patients labeled as cardiac arrest by dispatchers who are found to have confirmed cardiac arrest. Positive likelihood ratio = the likelihood of a patient with confirmed cardiac arrest to be labeled positive compared with a person without cardiac arrest (the higher the likelihood ratio, the better the test to rule in cardiac arrest). Negative likelihood ratio = the likelihood of a patient with confirmed cardiac arrest to be labeled negative compared with a person without cardiac arrest (the smaller the likelihood ratio, the better the test to rule out cardiac arrest).
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, - Fukushima H.
- Panczyk M.
- Hu C.
- et al.
Description of abnormal breathing is associated with improved outcomes and delayed telephone cardiopulmonary resuscitation instructions.
J Am Heart Assoc. 2017; 6e005058https://doi.org/10.1161/JAHA.116.005058
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.†Patients strictly with confirmed OHCA.
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.§All patients inclusive of those without and with confirmed OHCA.
We compared subgroups of studies that used predetermined or proprietary dispatching algorithms with those that used less structured criteria for diagnosis of cardiac arrest (dispatch algorithms versus criteria-based dispatch) and studies that reported different credential or training requirements for emergency dispatchers. No identifiable differences were noted in these subgroup analyses. Heterogeneity in studies and lack of adjusted analyses precluded meta-analysis for any subgroup.
Treatment Recommendations
We recommend that dispatch centers implement a standardized algorithm and/or standardized criteria to immediately determine if a patient is in cardiac arrest at the time of emergency call (strong recommendation, very-low-certainty evidence).
We suggest that dispatch centers monitor and track diagnostic capability.
We suggest that dispatch centers look for ways to optimize sensitivity (minimize false negatives).
We recommend high-quality research that examines gaps in this area.
Justification and Evidence-to-Decision Framework Highlights
The evidence-to-decision table is included in Appendix ASupplement Appendix A-1. In making these new recommendations, we prioritized the desirable benefits (increase in potential lifesaving treatment) that would result from the immediate accurate identification of cardiac arrest by dispatchers. These benefits include the provision of DA-CPR and dispatching of appropriate EMS resources compared with the undesirable consequences of lack of early recognition of the event, such as delays to CPR and AED use. We realize that efforts to minimize the frequency of undertriage (false-negative) may increase the frequency of overtriage (false-positive cases). Importantly, whether in cardiac arrest or not, the potential acuity of such patients still demands the need for immediate EMS assistance at the scene. In tiered response systems, if first-arriving EMS responders find a less emergent situation on arrival, the need for a secondary advanced life support (ALS) response could be cancelled. In either event, the consequences of failing to recognize a genuine cardiac arrest in a timely manner is significant enough to justify some false-positive events. By comparison, the default position of most trauma systems is to have a high overtriage rate and a low undertriage rate because of similar concerns.
We were unable to make any recommendations on specific algorithms or criteria for identification of cardiac arrest because the variability across studies did not allow for direct comparisons or pooling of data. Furthermore, as the result of unexplained variability across studies, even those using similar dispatch criteria, there was considerable variation in their diagnostic accuracy, which prevented pooling of data to find overall diagnostic accuracy measures for each of the algorithms. One factor that significantly influences the diagnostic accuracy is the prevalence of cardiac arrest in the reported population. In multiple studies, the denominator of calls was different—some studies reporting cardiac arrests as a proportion of all emergency calls, others reporting cardiac arrests as a proportion of calls in which patients were described as being unresponsive, and still other studies that (retrospectively) only included patients who were actually in cardiac arrest at the time of the call. Reporting the accuracy of identifying a cardiac arrest as a proportion of all emergency calls can also produce misleadingly favorable diagnostic statistics because, for the majority of such calls, it is obvious at the time that the patient is not in cardiac arrest.
Last, although studies that examined barriers to cardiac arrest identification were identified, these studies were not done in a manner that enabled calculation of the effect of these characteristics on OHCA diagnosis or on dispatcher performance.
Knowledge Gaps
Current knowledge gaps include but are not limited to the following:
- •Are there other potentially important criteria or ancillary tools that might improve dispatcher recognition of cardiac arrest in addition to standard dispatch algorithms? These might include use of a remote video link or pulse detection technologies via a caller’s mobile telephone.
- •What are potential obstacles to dispatcher recognition of cardiac arrest (eg, language barriers, caller characteristics, patient characteristics)?
- •Could the use of artificial intelligence improve recognition of cardiac arrest compared with emergency medical dispatcher recognition?
- •What are the operational costs required for implementing and monitoring dispatcher recognition programs?
- •What is the most accurate dispatch algorithm, and what are the optimal criteria for rapidly recognizing cardiac arrest?
- •What is the relationship between dispatch algorithms and time to cardiac arrest recognition and time to initiation of DA-CPR?
Dispatcher Instructions in CPR (BLS 359: SysRev)
DA-CPR has been reported in individual studies to significantly increase the rate of bystander CPR and survival from cardiac arrest. We undertook a SysRev and meta-analysis to evaluate the impact of DA-CPR programs on key clinical outcomes after OHCA.
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Consensus on science, values, preferences, and task force insights and knowledge gaps can be found in the 2019 International Consensus on CPR and ECC Science With Treatment Recommendations.”7
, - Soar J.
- Maconochie I.
- Wyckoff M.H.
- et al.
2019 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Pediatric Life Support; Neonatal Life Support; Education, Implementation, and Teams; and First Aid Task Forces.
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Population, Intervention, Comparator, Outcome, Study Design, and Time Frame
- •Population: Adults with presumed OHCA
- •Intervention: Patients/cases or EMS systems for which DA-CPR is offered
- •Comparators: Studies with comparators in which either systems or specific cardiac arrest patients/cases were not offered DA-CPR were included
- •Outcomes: Critical—survival with favorable neurological function (at hospital discharge, 1 month, or 6 months), survival (to hospital discharge, 1 month, or 1 year), short-term survival (return of spontaneous circulation [ROSC], hospital admission), provision of bystander CPR; important—initial shockable rhythm, time to CPR
- •Study designs: RCTs and nonrandomized studies (non-RCTs, interrupted time series, controlled before-and-after studies, cohort studies) eligible for inclusion
- •Time frame: All years and all languages included with the last search, performed July 1, 2018; ongoing or unpublished studies identified through a search of ClinicalTrials.gov online registry
- •PROSPERO registration: CRD42018091427
Treatment Recommendations
We recommend that emergency medical dispatch centers have systems in place to enable call handlers to provide CPR instructions for adult patients in cardiac arrest (strong recommendation, very-low-certainty evidence).
We recommend that emergency medical dispatchers provide CPR instructions (when deemed necessary) for adult patients in cardiac arrest (strong recommendation, very-low-certainty evidence).
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, - Soar J.
- Maconochie I.
- Wyckoff M.H.
- et al.
2019 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Pediatric Life Support; Neonatal Life Support; Education, Implementation, and Teams; and First Aid Task Forces.
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DA-Assisted Compression-Only CPR Versus Conventional CPR (BLS 359: SysRev)
Emergency medical dispatchers typically are trained to provide telephone instructions for both compression-only CPR and conventional CPR with mouth-to-mouth ventilations. There is still some degree of controversy about whether it is sufficient for dispatchers to instruct callers to do only compression-only CPR for adult cardiac arrests or whether it is feasible to teach untrained lay rescuers over the phone how to perform mouth-to-mouth ventilation. This topic has been included in a SysRev and meta-analysis.
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The task force CoSTR as well as values and preferences can be found in the 2017 International Consensus on CPR and ECC Science With Treatment Recommendations Summary.64
These note that the treatment recommendations prioritized the effective treatment for the most common causes of cardiac arrest (ie, cardiac causes). There remains uncertainty about the optimal approach when the cardiac arrest is caused by noncardiac causes, especially hypoxia.Population, Intervention, Comparator, Outcome, Study Designs, and Time Frame
- •Population: Adults and children with OHCA
- •Intervention: Dispatcher-assisted compression-only CPR
- •Comparator: Dispatcher-assisted standard CPR
- •Outcome: The primary outcome was favorable neurological outcomes, measured by cerebral performance or a modified Rankin scale. Secondary outcomes were survival, ROSC, and quality of life.
- •Study design: RCTs and nonrandomized studies (non-RCTs, interrupted time series, controlled before-and-after studies, cohort studies) were eligible for inclusion. Study designs without a comparator group (ie, case series, cross-sectional studies), reviews, and pooled analyses were excluded.
- •Time frame: Published studies in English were searched on January 15, 2016.
- •PROSPERO registration: CRD42016047811
Treatment Recommendation
We recommend that dispatchers provide chest compression–only CPR instructions to callers for adults with suspected OHCA (strong recommendation, low-certainty evidence).
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Compression-Only CPR
One of the primary measures taken to improve survival after cardiac arrest is a focused effort to improve the quality of CPR. Although the impact of high-quality chest compressions has been studied extensively,
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the role of ventilation and oxygenation in the initial management of cardiac arrest is less clear. Shortly after the publication of the 2015 International Consensus on CPR and ECC Science With Treatment Recommendations,”3
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a 23 711-patient RCT evaluating the effectiveness of continuous chest compressions (during which ventilations were given without pausing chest compressions) in the EMS setting was published.70
In parallel, developments of large national and regional registries are continually providing new insights into the epidemiology of cardiac arrest and effects of bystander CPR on outcomes.71
These emerging publications generated an urgent need to review all available evidence on continuous compression strategies to provide an updated evidence evaluation that includes the latest science available. This topic has been included in a 2017 SysRev and meta-analysis.63
The BLS Task Force CoSTR and its values and preferences can be found in the 2017 CoSTR summary.64
Lay Rescuer Chest Compression–Only Versus Standard CPR (BLS 547 SysRev)
Population, Intervention, Comparator, Outcome, Study Designs, and Time Frame
- •Population: Adults and children with OHCA
- •Intervention: Lay rescuer compression-only CPR
- •Comparators: Lay rescuer standard CPR
- •Outcomes: The primary outcome was favorable neurological outcomes, measured by cerebral performance or a modified Rankin scale. Secondary outcomes were survival, ROSC, and quality of life.
- •Study designs: RCTs and nonrandomized studies (non-RCTs, interrupted time series, controlled before-and-after studies, cohort studies) were eligible for inclusion. Study designs without a comparator group (ie, case series, cross-sectional studies), reviews, and pooled analyses were excluded.
- •Time frame: Published studies in English were searched on January 15, 2016.
- •PROSPERO registration: CRD42016047811
Treatment Recommendations
We continue to recommend that bystanders perform chest compressions for all patients in cardiac arrest (good practice statement).
We suggest that bystanders who are trained, able, and willing to give rescue breaths and chest compressions do so for all adult patients in cardiac arrest (weak recommendation, very-low-certainty evidence).
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EMS Chest-Compression-Only Compared With Conventional CPR (BLS 360: SysRev)
Population, Intervention, Comparator, Outcome, Study Design, and Time Frame
- •Population: Adults and children with OHCA treated by EMS
- •Intervention: Compression-only CPR or minimally interrupted CPR (protocol for resuscitation based on commencing an initial 200 uninterrupted chest compressions and passive oxygen insufflation).
- •Comparators: Standard CPR
- •Outcomes: The primary outcome was favorable neurological outcomes, measured by cerebral performance or a modified Rankin scale. Secondary outcomes were survival, ROSC, and quality of life.
- •Study designs: RCTs and nonrandomized studies (non-RCTs, interrupted time series, controlled before-and-after studies, cohort studies) were eligible for inclusion. Study designs without a comparator group (ie, case series, cross-sectional studies), reviews, and pooled analyses were excluded.
- •Time frame: Published studies in English were searched on January 15, 2016.
- •PROSPERO registration: CRD42016047811
Treatment Recommendations
We recommend that EMS providers perform CPR with 30 compressions to 2 ventilations (30:2 ratio) or continuous chest compressions with positive pressure ventilation delivered without pausing chest compressions until a tracheal tube or supraglottic device has been placed (strong recommendation, high-certainty evidence).
We suggest that, when EMS systems have adopted minimally interrupted cardiac resuscitation, this strategy is a reasonable alternative to conventional CPR for witnessed shockable OHCA (weak recommendation, very-low-certainty evidence).
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In-Hospital Chest Compression-Only CPR Versus Conventional CPR (BLS 372: SysRev)
Population, Intervention, Comparator, Outcome, Study Designs, and Time Frame
- •Population: Adults and children with in-hospital cardiac arrest (IHCA)
- •Intervention: Compression-only CPR
- •Comparators: Standard CPR
- •Outcomes: The primary outcome was favorable neurological outcomes, measured by cerebral performance or a modified Rankin scale. Secondary outcomes were survival, ROSC, and quality of life.
- •Study designs: RCTs and nonrandomized studies (non-RCTs, interrupted time series, controlled before-and-after studies, cohort studies) were eligible for inclusion. Study designs without a comparator group (ie, case series, cross-sectional studies), reviews, and pooled analyses were excluded.
- •Time frame: Published studies in English were searched on January 15, 2016.
- •PROSPERO registration: CRD42016047811
Treatment Recommendation
Whenever tracheal intubation or a supraglottic airway is achieved during in-hospital CPR, we suggest that providers perform continuous compressions with positive pressure ventilation delivered without pausing chest compressions (weak recommendation, very-low-certainty evidence).
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Rescuer Fatigue in Chest Compression–Only CPR (BLS 349: ScopRev)
Rationale for Review
This topic was not a part of the 2017 SysRev and CoSTR summary on continuous compressions versus standard CPR.
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It was prioritized by the BLS Task Force for an updated evidence review, because this topic had not been reviewed by ILCOR since 2005.Population, Intervention, Comparator, Outcome, Study Designs, and Time Frame
- •Population: Rescuers performing CPR
- •Intervention: Compression-only CPR
- •Comparators: Standard CPR
- •Outcomes: Rescuer fatigue, CPR quality parameters (compression rate, compression depth, compression pauses, leaning or incomplete release, etc)
- •Study designs: RCTs, interrupted time series, controlled before-and-after studies, cohort studies, and manikin studies were eligible for inclusion.
- •Time frame: All years and all languages were included as long as there was an English abstract; unpublished studies (eg, conference abstracts, trial protocols) were excluded. The literature search was updated to October 29th, 2019.
Summary of Evidence
This ScopRev is included in Appendix BSupplement Appendix B-1. Fifteen manikin studies evaluating fatigue at various compression-to-ventilation ratios were identified. These studies compared fatigue and its effects on CPR quality in volunteers performing continuous compressions and 30:2 or 15:2 CPR.
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Evidence from these manikin studies comparing fatigue and effects on CPR quality suggest that continuous compressions are effective in the first 2 minutes with regard to depth and frequency, and there are indications that short periods of rest (pauses in compression) reduce rescuer fatigue and increase CPR quality.Task Force Insights
Continuous compression strategies increasingly have been advocated in an effort to increase overall bystander CPR rates. Evidence reviews evaluating the effect of continuous chest compressions versus standard CPR on critical outcomes, such as long-term survival, have been performed by the BLS Task Force in a separate published CoSTR.
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Although the BLS Task Force regards rescuer fatigue as an important barrier to high-quality bystander CPR, a higher value is placed on patient-centered outcomes.
Treatment Recommendation
This treatment recommendation (below) is unchanged from 2015.
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We suggest pausing chest compressions every 2 minutes to assess the cardiac rhythm (weak recommendation, low-certainty evidence).
In making this recommendation, we placed a high priority on consistency with previous recommendations and the absence of contradictory evidence to prompt a change. We placed value on simplifying resuscitation logistics by coordinating rhythm and pulse checks with standard recommendations for rotating the provider performing chest compressions every 2 minutes.
CPR Sequence
Firm Surface for CPR (BLS 370: SysRev)
Rationale for Review
This topic was prioritized for review by the BLS Task Force because it had not been updated since 2010.
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Members of the task force reported variation in backboard use and the practice of moving a patient from the bed to the floor to improve the quality of CPR, so it was considered timely to review the published evidence.Population, Intervention, Comparator, Outcome, Study Design, and Time Frame
- •Population: Adults or children in cardiac arrest (OHCA and IHCA) on a bed
- •Intervention: CPR on a hard surface (eg, backboard, floor, deflatable or specialist mattress) Comparators: CPR on a regular mattress
- •Outcomes: Survival, survival with a favorable neurological outcome, ROSC, CPR quality
- •Study designs: RCTs and nonrandomized studies (non-RCTs, interrupted time series, controlled before-and-after studies, cohort studies) were eligible for inclusion. Randomized manikin/simulation/cadaver studies were only included if insufficient human studies were identified. Unpublished studies (eg, conference abstracts, trial protocols), nonrandomized manikin/simulation/cadaver studies, animal studies, experimental/laboratory models, mathematical models, narrative reviews, and editorials and opinions with no primary data were excluded.
- •Time frame: January 1, 2009, to September 16, 2019
- •PROSPERO registration: CRD42019154791
Consensus on Science
The identified science has been grouped under the following subheadings: mattress type, floor compared with bed, and backboard in Table 2.
Table 2Firm Surface for CPR.
| Group | Certainty | Studies | No. of Participants | Results |
|---|---|---|---|---|
| Mattress type | Low (serious indirectnesss) | Three manikin RCTs† 87 , 88 , 89 , 90 | 33 | No study identified a difference in chest compression depth between mattress types |
| Floor compared with bed | Low (serious indirectness) | Two manikin RCTs (meta-analysed) 88 , 91 | 64 | No effect on chest compression depth: mean difference 4.29 mm (95% CI, -0.70 to 9.27) |
| Two manikin RCTs† 89 , 92
Effect of using a home-bed mattress on bystander chest compression during out-of-hospital cardiac arrest. Hong Kong J Emerg Med. 2019; (Accessed March 20, 2020)https://doi.org/10.1177/1024907919856485 | 34 | Neither study identified a difference in chest compression depth between groups | ||
| Backboard use | Low (serious indirectness) | Six manikin RCTs (meta-analysed) 90 , 93 , 94 , 95 , 96 , 97 | 221 | Improved chest compression depth: mean difference 2.74 mm (95% CI, 1.19 to 4.28) |
| One manikin RCT† 98 | 24 | No difference in chest compression depth between groups |
†Heterogeneity precluded meta-analysis.
CPR indicates cardiopulmonary resuscitation; and RCT, randomized controlled trial.
Treatment Recommendations
We suggest performing manual chest compressions on a firm surface when possible (weak recommendation, very-low-certainty evidence)
During IHCA, we suggest that, when a bed has a CPR mode that increases mattress stiffness, it should be activated (weak recommendation, very-low-certainty evidence).
During IHCA, we suggest against moving a patient from a bed to the floor to improve chest compression depth (weak recommendation, very-low-certainty evidence).
The confidence in effect estimates is so low that the task force was unable to make a recommendation about the use of a backboard strategy.
Justification and Evidence-to-Decision Framework Highlights
The evidence-to-decision table is included in Appendix ASupplement Appendix A-2.
The context for this question was that, when manual chest compressions are performed on a mattress, the compression force is dissipated through both chest compression and compression of the mattress under the patient. Manikin models indicate that the amount of mattress compression ranges from 12% to 57% of total compression depth, with softer mattresses compressed the most.
87
, 90
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This mattress compression can lead to reduced spinal-sternal displacement and a reduction in effective chest compression depth.Effective compression depths can be achieved even on a soft surface, providing the CPR provider increases overall compression depth to compensate for mattress compression.
90
, 97
, 101
, 102
, 103
, 104
, 105
CPR feedback devices that account for mattress compression (eg, the use of dual accelerometers or increasing compression depth targets) can help CPR providers ensure adequate compression depth when CPR is performed on a mattress.- Ruiz de Gauna S.
- González-Otero D.M.
- Ruiz J.
- Gutiérrez J.J.
- Russell J.K.
A feasibility study for measuring accurate chest compression depth and rate on soft surfaces using two accelerometers and spectral analysis.
Biomed Res Int. 2016; 20166596040https://doi.org/10.1155/2016/6596040
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, 99
, 101
, 103
,105
, - Ruiz de Gauna S.
- González-Otero D.M.
- Ruiz J.
- Gutiérrez J.J.
- Russell J.K.
A feasibility study for measuring accurate chest compression depth and rate on soft surfaces using two accelerometers and spectral analysis.
Biomed Res Int. 2016; 20166596040https://doi.org/10.1155/2016/6596040
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In making these recommendations, the task forces highlight the importance of high-quality chest compressions for optimizing outcomes from cardiac arrest.
The task force noted that there were no clinical studies reporting on the critical outcomes of survival and favorable neurological outcome or important outcome of chest compression quality.
The weak recommendations are based on extrapolation from manikin studies, typically undertaken on a mattress placed on a hospital bed, for which manual CPR was performed by a trained healthcare professional. The hospital beds involved in the studies typically had rigid bases. The task force noted that, although this configuration is common in many developed country hospitals, it may not be applicable to all hospitals or the out-of-hospital setting. The absence of studies simulating out-of-hospital settings (where beds may be softer) and in which the CPR provider may be a single untrained rescuer led the task force to focus recommendations on the in-hospital setting.
The task force supported performing manual chest compressions on a firm surface when possible because this reduces the risks of shallow compressions attributable to performing CPR on a soft surface. On the other hand, moving a patient onto a hard surface can be a major barrier to CPR, and the importance of performing CPR on a firm surface needs to be weighed against the likelihood of significant delay in providing CPR. In the setting of DA-CPR, in particular, logistical aspects of moving patients from bed to floor can impede if not thwart the performance of CPR.
The task force considered that, when a mattress with CPR function was available, activating a CPR function on a mattress, although unlikely to substantially improve compression depth, posed a low risk of harm to rescuers and patients, leading to a weak recommendation of support.
In considering whether to transfer a patient from a hospital bed to the floor to improve compression depth, the task force considered that the risks of harm (eg, interruption in CPR, risk of losing vascular access for intravenous lines, and more confined space) to the patient and resuscitation team outweighed any small improvement in chest compression depth, leading to a weak recommendation against routine use of this practice.
The task force was unable to make a recommendation for the use of a CPR backboard during IHCA. Within the limitations of manikin studies, the available evidence indicates a marginal benefit to chest compression depth from use of a backboard. For example, placing a firm surface (eg, a backboard) between the patient and a soft surface may merely transfer the same force from CPR to the underlying softness and not obviate potential concern over chest compression depth. No studies specifically evaluated backboard deployment or any impact this has on interruptions to chest compressions and/or displacement of tubes and lines during insertion. For healthcare systems that have already incorporated backboards into routine use during IHCA, the evidence was considered insufficient to suggest against their continued use. For healthcare systems that have not introduced backboards, the limited improvement in compression depth and uncertainty about harms seemed insufficient to justify the costs of purchasing backboards and training staff in their use. When backboards are deployed, users should be aware that mattress stiffness, backboard size (larger is better), and orientation (longitudinal is better) influence their effectiveness.
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Knowledge Gaps
Current knowledge gaps include but are not limited to the following:
- •Studies reporting clinical outcomes
- •Studies examining the logistical aspects of backboard deployment or moving a patient from a bed to the floor
- •Studies relevant to OHCA
- •Studies in both high- and low-resource settings, in which hospital bed or prehospital stretcher configurations may vary
Starting CPR (C-A-B Compared With A-B-C) (BLS 661: SysRev)
Although, internationally, most adult BLS guidelines recommend commencing chest compressions before rescue breaths, debate about this sequence continues. In addition, there is variability in the sequences used for pediatric resuscitation and for aquatic rescue, with different approaches in various jurisdictions.
Population, Intervention, Comparator, Outcome, Study Design, and Time Frame
- •Population: Adults and children with OHCA
- •Intervention: Commencing CPR beginning with compressions first (30:2)
- •Comparators: CPR beginning with ventilation first (2:30)
- •Outcomes: Survival with favorable neurological/functional outcome at discharge, 30 days, 60 days, 180 days, and/or 1 year; survival only at discharge, 30 days, 60 days, 180 days, and/or 1 year; and ROSC
- •Study designs: RCTs and nonrandomized studies (non-RCTs, interrupted time series, controlled before-and-after studies, cohort studies) were eligible for inclusion.
- •Exclusion criteria: Unpublished studies (eg, conference abstracts, trial protocols) and animal studies were excluded. Studies of dispatcher- or telephone-assisted CPR were excluded.
- •Time frame: All languages were included as long as there was an English abstract. The literature search was updated in September 2019.
Consensus on Science
This current SysRev did not identify any additional human or manikin studies published since the 2015 CoSTR SysRev.
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The published evidence remains limited to 4 manikin studies: 1 randomized study112
focused on adult resuscitation, 1 randomized study focused on pediatric resuscitation,- Marsch S.
- Tschan F.
- Semmer N.K.
- Zobrist R.
- Hunziker P.R.
- Hunziker S.
ABC versus CAB for cardiopulmonary resuscitation: a prospective, randomized simulator-based trial.
Swiss Med Wkly. 2013; 143w13856https://doi.org/10.4414/smw.2013.13856
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and 2 observational studies focused on adult resuscitation.114
, 115
The results from these studies are summarized in Table 3.Table 3Starting CPR.
| Outcome | Certainty | Studies | No. of Patients | Results |
|---|---|---|---|---|
| Time to commencement of chest compressions | Very low | 1 RCT (manikin): Lubrano 2012 113 | 155 two-person teams | Statistically significant 24-second difference (P<0.05) in favor of C-A-B |
| 2 observational (manikin): Kobayashi 2008, 107 Sekiguchi 2013114 , 115 | 40 individual rescuers 115 and 33 six-person teams114 | The observational studies found statistically significant decreases of 20 s (P<0.001) 115 and 26 s (P<0.001)114 in favor of C-A-B. | ||
| Time to commencement of rescue breaths | Very low | 2 RCTs (manikin): Marsch 2013, Lubrano 2012 112 ,
ABC versus CAB for cardiopulmonary resuscitation: a prospective, randomized simulator-based trial. Swiss Med Wkly. 2013; 143w13856https://doi.org/10.4414/smw.2013.13856 113 | 210 two-person teams | In a respiratory arrest scenario, there was a 4-second difference (P<0.05) in favor of C-A-B 113 ; in a cardiac arrest scenario, A-B-C decreased the time to commencement of rescue breaths by 6 s (P<0.05), and C-A-B decreased time to commencement of rescue breaths by 5 s (P<0.05).112
ABC versus CAB for cardiopulmonary resuscitation: a prospective, randomized simulator-based trial. Swiss Med Wkly. 2013; 143w13856https://doi.org/10.4414/smw.2013.13856 |
| Time to completion of first CPR cycle (30 chest compressions and 2 rescue breaths) | Very low | 1 RCT (manikin): Marsch 2013 112
ABC versus CAB for cardiopulmonary resuscitation: a prospective, randomized simulator-based trial. Swiss Med Wkly. 2013; 143w13856https://doi.org/10.4414/smw.2013.13856 | 55 two-person teams | C-A-B decreased time to completion of first CPR cycle by 15 s (P<0.001). |
A-B-C indicates airway-breathing-circulation; C-A-B, circulation-airway-breathing; CC, chest compression; and RCT, randomized controlled trial.
The overall certainty of evidence was rated as very low for all outcomes primarily because of a very serious risk of bias and indirectness. The individual observational studies were all at a critical risk of bias because of confounding, and the RCTs were all at critical risk of bias because of lack of blinding. Because of this and a high degree of heterogeneity, no meta-analyses could be performed. Individual studies are difficult to interpret.
Treatment Recommendation
This treatment (below) is unchanged from 2015.
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We suggest commencing CPR with compressions rather than ventilation in adults with cardiac arrest (weak recommendation, very-low-certainty evidence).
Justification and Evidence-to-Decision Framework Highlights
The evidence-to-decision table is included in Appendix ASupplement Appendix A-3. No change was made to this adult treatment recommendation. For all outcomes, starting CPR with compressions resulted in faster times to key elements of resuscitation (rescue breaths, chest compressions, completion of first CPR cycle) across the 4 papers reviewed, with the exception of simulated pediatric resuscitation, for which starting with compressions delayed time to commencement of rescue breaths in cardiac arrest by 6 seconds. This difference was statistically significant but reflects a delay that is not considered clinical significant.
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This delay in commencing rescue breaths may be acceptable given the decreased time to other elements of resuscitation; however, the certainty of the evidence is very low, and all studies reviewed were manikin studies. There is no clinical evidence to guide whether to initiate compressions before ventilation in adult cardiac arrest. There should also be consideration given to the impact of simplification of training requirements of a single approach compared with separate approaches for adults and children.Knowledge Gaps
- •No human studies evaluating this question in any setting were identified.
- •Important uncertainties regarding timing and delays in initiation of the CPR components (chest compressions, opening airway, and rescue breaths) remain and may not be readily extrapolated from manikin studies.
CPR Before Call for Help (BLS 1527: SysRev)
This question was suggested by the resuscitation community during the public commentary process. The question of optimal sequence for calling for help and starting CPR is frequent during CPR training courses, and a SysRev of the literature to guide recommendations was therefore prioritized by the BLS Task Force. Searching for new science from the era of increased availability of communication devices and hands-free alternatives for lone rescuers was also considered important in this evidence review.
Population, Intervention, Comparator, Outcome, Study Design, and Time Frame
- •Population: Adults and children with OHCA
- •Intervention: CPR before call for help; immediate CPR performed for a short time interval (ie, 1 minute) before alerting EMS dispatch center
- •Comparators: An immediate call for help to the EMS dispatch center by a lone bystander with a mobile phone
- •Outcomes: Survival with favorable neurological outcome until and beyond hospital discharge or 30 days; survival until and beyond hospital discharge or 30 days; ROSC
- •Study designs: We included RCTs, nonrandomized studies, and case series with at least 5 cases. We considered papers in all languages provided there was an English language abstract available for review. We excluded unpublished studies, conference abstracts, manikin or simulation studies, narrative reviews, editorials or opinions with no primary data, animal studies and experimental/laboratory models.
- •Time frame: All years and all languages were included as long as there was an English abstract; unpublished studies (eg, conference abstracts, trial protocols) were excluded. The literature search was updated to October 2019.
Consensus on Science
For the critical outcome of survival with favorable neurological outcome, we identified only a single observational study.
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The overall certainty of evidence was rated as very low because of a very serious risk of bias. With the identification of only 1 study, no meta-analyses were performed.For the critical outcome of survival with favorable neurological outcome, we identified very-low-certainty evidence (downgraded for very serious risk of bias) from 1 cohort study including 17 461 OHCA occurrences from Japan (2005–2012), which showed no benefit from a “CPR-first” strategy (cohort of 5 446 OHCA patients) compared with a “call-first” strategy (cohort of 1 820 OHCA patients).
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Adjusted analyses were performed on various subgroups and suggested significant improvements in survival with a favorable neurological outcome with a “CPR-first” strategy compared with a “call-first” strategy for noncardiac etiology OHCA (adjusted odds ratio [AOR], 2.01; 95% CI, 1.39–2.9); under 65 years of age (AOR, 1.38; 95% CI, 1.09–1.76); under 20 years of age (AOR, 3.74; 95% CI, 1.46–9.61); and both under 65 years of age and noncardiac etiology together (AOR, 4.31; 95% CI, 2.38–8.48).
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Treatment Recommendation
We recommend that a lone bystander with a mobile phone should dial EMS, activate the speaker or other hands-free option on the mobile phone, and immediately begin CPR with dispatcher assistance, if required (strong recommendation, very-low-certainty evidence).
Justification and Evidence-to-Decision Framework Highlights
The evidence-to-decision table is included in Appendix ASupplement Appendix A-4. This SysRev was based on a new PICOST question suggested during public commenting and, therefore, includes a new treatment recommendation. The included paper analyzed only 17 461 OHCA occurrences from 925 288 recorded in the national registry in the period from 2005 to 2012. Analysis was limited to cases in which lay rescuers witnessed the OHCA and spontaneously performed CPR (without the need for dispatcher assistance), and the groups compared were different with respect to age, gender, initial rhythm, bystander CPR characteristics, and EMS intervals. Although some factors were adjusted for in subgroup analysis, there is significant risk of confounding. Despite very-low-certainty evidence, there was consensus among the BLS Task Force to make a strong recommendation.
There were many exclusion criteria: unwitnessed, prehospital involvement of physician or unknown, EMS-witnessed OHCA, bystander-witnessed cases with missing data on time to intervention, no bystander CPR, DA-CPR, no intervention in 0 to 1 minutes, no CPR at all within 4 minutes, and etiology (cardiac or noncardiac) unknown.
There were some benefits noted in subgroup analyses, but these groups were not specified a priori. We cannot expect a bystander to reliably determine whether a cardiac arrest is of cardiac or noncardiac etiology. The results are not generalizable to all OHCA because they refer specifically to bystander-witnessed cases in which the bystander spontaneously initiates CPR after only a short delay.
The timings of interventions were determined after the event by EMS personnel who interviewed the bystanders. These timings may be imprecise or inaccurate in an undetermined number of cases.
The wide availability of mobile phones may reduce the likelihood that a lone bystander would have to leave a victim to phone EMS. Pragmatically, it is now often possible to perform both actions simultaneously, and the focus should be on empowering people to recognize OHCA and initiate both an EMS call and CPR as soon as possible. In the absence of any evidence to the contrary, this would apply to both witnessed and nonwitnessed OHCA, except in circumstances when there are appropriate reasons not to start CPR. When more than 1 bystander is at the scene, calling EMS and initiating CPR can be performed simultaneously. For the single rescuer, a call-first strategy ensures that EMS providers are dispatched as soon as possible, bringing additional assets (including a defibrillator) that might otherwise be delayed by a later call. Telecommunicator prompting may promote the initiation of bystander CPR that might not otherwise occur or may support better quality CPR (eg, instructing the caller to press hard and count aloud, helping to pace the compression rate).
In the situation when a lone rescuer would have to leave a victim alone to dial EMS, the priority is prompt activation of EMS before subsequently returning to the victim to initiate CPR as soon as possible.
Knowledge Gaps
There is no evidence comparing an immediate call to EMS for help with a call after 1 minute of CPR in the specific circumstance of a lone bystander with a mobile phone. There is also no evidence about how long it takes to call EMS after a witnessed cardiac arrest. The delay between a witnessed arrest and a call to EMS may be substantial.
Duration of CPR Cycles (2 Minutes Versus Other) (BLS 346: SysRev)
Rationale for Review
The recommendations for CPR cycle duration have changed with time, but these changes have never been based on high-certainty evidence that 1 specific interval or CPR cycle duration was superior in terms of patient survival. Because the topic has not been reviewed since 2015, when no direct evidence was identified, the following PICOST question was prioritized for evidence review.
Population, Intervention, Comparator, Outcome, Study Design, and Time Frame
- •Population: Adults and children with cardiac arrest
- •Intervention: Pausing chest compressions at another interval
- •Comparators: Pausing chest compressions every 2 minutes to assess the cardiac rhythm
- •Outcomes: Survival to hospital discharge with good neurological outcome and survival to hospital discharge were ranked as critical outcomes. ROSC was ranked as an important outcome.
- •Study designs: RCTs and nonrandomized studies (non-RCTs, interrupted time series, controlled before-and-after studies, cohort studies) were eligible for inclusion.
- •Time frame: All years and all languages were included as long as there was an English abstract; unpublished studies (eg, conference abstracts, trial protocols) were excluded. The literature search was updated to September 2019.
Consensus on Science
Data were derived from 2 RCTs for which the principal focus was on the period of time allotted for CPR before the first rhythm analysis. Assessment of the duration (in minutes) of uninterrupted CPR between subsequent rhythm checks and outcome were not formally reported analyses in either study. The published data in these 2 studies enabled an ad hoc analysis by ILCOR evidence evaluation experts that indirectly addressed this question. Outcomes were not adjusted for possible confounders.
-Minute CPR Duration Compared With 3-Minute Duration for Postshock Ventricular Fibrillation (VF)/Pulseless Ventricular Tachycardia (pVT)
In the 1 study including 1-minute and 3-minute durations of uninterrupted CPR between rhythm checks,
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the control group included patients who received immediate defibrillation (up to 3 stacked shocks) for VF/VT followed by 1 minute of CPR for patients in refractory VF/VT at the next rhythm check and 3 minutes of CPR for those patients who exhibited nonshockable rhythms after 1 to 3 shocks. The intervention group included patients who received 3 minutes of CPR before the first defibrillation attempt (up to 3 stacked shocks) for VF/VT followed by CPR for 3 minutes regardless of postshock rhythm. Of note, none of the patients received 2-minute periods of CPR. This RCT showed no benefit from the intervention compared with the control CPR duration between rhythms checks for all of the outcomes listed (Table 4).Table 41-Minute CPR Duration Compared With 3-Minute Duration for Postshock VF/pVT
| Outcome | Certainty | Studies | No. of Patients | Results |
|---|---|---|---|---|
| Hospital discharge with favorable neurological outcome | Low (risk of bias, imprecision) | RCT: Wik 2003 117 | 200 | No difference: Relative risk 1.68 (95% CI, 0.85–3.32), 78 more patients/1000 (−17 to 266) |
| Survival to hospital discharge | Low (risk of bias, imprecision) | RCT: Wik 2003 117 | 200 | No difference: Relative risk 1.52 (95% CI, 0.83–2.77), 76 more patients/1000 (−25 to 258) |
| ROSC | Low (risk of bias, imprecision) | RCT: Wik 2003 117 | 200 | No difference: Relative risk 1.22 (95% CI, 0.92–1.50), 101 more patients/1000 (−37 to 229) |
95% CI indicates 95% confidence interval; CPR, cardiopulmonary resuscitation; RCT, randomized controlled trial; ROSC, return of spontaneous circulation; pVT, pulseless ventricular tachycardia; and VF, ventricular fibrillation.
Both relative and absolute risks are written as mean values (95% CIs).
-Minute CPR Duration Compared With 2-Minute CPR Duration
In the 1 study that included 1-minute and 2-minute durations of uninterrupted CPR between rhythm checks,
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the 2-minute group included patients who were enrolled in the RCT after implementation of new guidelines introducing single shocks, 30:2 CPR, and 2-minute CPR cycles between rhythm checks. The 1-minute group included patients who were enrolled in the RCT before implementation of new guidelines and were therefore treated with stacked shocks (up to 3 in refractory VF/VT), 15:2 CPR, and 1-minute CPR cycles between rhythm checks. No clear benefit from either the 1- or 2-minute duration between rhythm checks was observed (Table 5).Table 51-Minute CPR Duration Compared With 2-Minute CPR Duration.
| Outcome | Certainty | Studies | No. of Patients | Results |
|---|---|---|---|---|
| Survival to hospital discharge | Very low (serious risk of bias, indirectness, imprecision) | RCT: Baker 2008 118 | 202 | No difference: Relative risk 0.49 (95% CI, 0.23–1.06), 92 fewer patients/1000 (−139 to 11) |
| ROSC | Very low (serious risk of bias, indirectness, imprecision) | RCT: Baker 2008 118 | 202 | No difference: Relative risk 0.95 (95% CI, 0.73–1.24), 27 fewer patients/1000 (−144 to 128) |
95% CI indicates 95% confidence interval; CPR, cardiopulmonary resuscitation; RCT, randomized controlled trial; and ROSC, return of spontaneous circulation.
Both relative and absolute risks are written as mean values (95% CIs).
Treatment Recommendation
This treatment recommendation (below) is unchanged from 2015.
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We suggest pausing chest compressions every 2 minutes to assess the cardiac rhythm (weak recommendation, low-certainty evidence).
Justification and Evidence-to-Decision Framework Highlights
The evidence-to-decision table is included in Appendix ASupplement Appendix A-5. No change was made to this treatment recommendation. This topic was prioritized for review by the BLS Task Force because it had not been updated since the 2015 CoSTR. Although the current review identified 2 older studies that included comparisons of groups with different CPR durations between rhythm checks, each had significant limitations. Both studies were designed to address the question of CPR first compared with defibrillation first. As a result, the certainty of evidence derived from these studies is low, and recommendations regarding optimal duration of CPR before a scheduled rhythm analysis are seriously confounded.
In making the suggestion to pause chest compressions every 2 minutes to assess cardiac rhythm, we placed a high value on being consistent with previous recommendations and the only limited indirect evidence identified in this review. The BLS Task Force acknowledges that every change in guidelines comes with a significant risk and cost as CPR educators and providers are asked to change current practice and implement new treatment strategies for complex and high-stress medical emergencies.
Knowledge Gaps
- •Does the optimal CPR duration (ie, interval between rhythm analyses) differ for patients with different initial or postshock cardiac rhythms?
- •Does the duration between collapse and EMS arrival affect the optimal CPR duration/interval between rhythm checks?
- •Do different intervals between rhythm checks interfere with the overriding goal of minimizing interruptions in chest compressions?
- •What is the relationship between rescuer fatigue, chest compression quality, and the optimal CPR duration/interval between rhythm checks?
Check for Circulation During BLS (BLS 348: EvUp)
An EvUp (see Appendix ASupplement Appendix C-1) identified no evidence to justify a SysRev or a change in the 2015 treatment recommendation.
Future reviews could focus on combination/alternative techniques used to confirm presence of circulation: plethysmography, arterial pressure monitoring, end-tidal carbon dioxide (ETCO2), near infrared spectroscopy, ultrasound, and more.
Treatment Recommendation
Outside of the ALS environment, where invasive monitoring is available, there are insufficient data about the value of a pulse check while performing CPR. We therefore do not make a treatment recommendation regarding the value of a pulse check.
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Components of High-Quality CPR
Hand Position During Compressions (BLS 357: SysRev)
Rationale for Review
The recommendations for hand position during compressions have changed with time, but these changes have been based on only low- or very-low-certainty evidence, with no data demonstrating that a specific hand position was optimal in terms of patient survival. The topic has not been reviewed since 2015,
3
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when no direct evidence was identified, so the following PICOST question was prioritized for evidence review.Population, Intervention, Comparator, Outcome, Study Design, and Time Frame
- •Population: Adults and children with cardiac arrest
- •Intervention: Delivery of chest compressions on the lower half of the sternum
- •Comparison: Any other location for chest compressions
- •Outcomes: Any clinical outcome. Survival to hospital discharge with good neurological outcome and survival to hospital discharge were ranked as critical outcomes. ROSC was ranked as an important outcome. Physiological outcomes, such as blood pressure, coronary perfusion pressure, or ETCO2, also were considered important.
- •Study design: RCTs and nonrandomized studies (non-RCTs, interrupted time series, controlled before-and-after studies, cohort studies) were eligible for inclusion. Unpublished studies (eg, conference abstracts, trial protocols) were excluded.
- •Time frame: SysRev search strategy: All years and all languages were included as long as there was an English abstract.
Consensus on Science
There were no studies reporting the critical outcomes of favorable neurological outcome, survival, or the important outcome of ROSC. For the important outcome of physiological end points, we identified 3 very-low-certainty studies (downgraded for bias, indirectness, and imprecision).
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One crossover study in 17 adults with prolonged resuscitation from nontraumatic cardiac arrest observed improved peak arterial pressure during compression systole (114 ± 51 mm Hg compared with 95 ± 42 mm Hg) and ETCO2 (11.0 ± 6.7 mm Hg compared with 9.6 ± 6.9 mm Hg) when compressions were performed over the lower third of the sternum compared with the center of the chest, but arterial pressure during compression recoil, peak right atrial pressure, and coronary perfusion pressure did not differ.120
A second crossover study in 30 adults with cardiac arrest observed no difference in ETCO2 values resulting from changes in hand placement.121
A third crossover study in 10 children observed higher peak systolic pressure and higher mean arterial pressure when compressions were performed on the lower third of the sternum compared with the middle of the sternum.119
Treatment Recommendation
This treatment recommendation (below) is unchanged from 2015.
3
We suggest performing chest compressions on the lower half of the sternum on adults in cardiac arrest (weak recommendation, very-low-certainty evidence).
Justification and Evidence-to-Decision Framework Highlights
The evidence-to-decision table is included in Appendix ASupplement Appendix A-6. In making this recommendation, we placed high value on consistency with current treatment recommendations in the absence of compelling clinical data suggesting the need to change the recommended hand placement for performing chest compressions.
Knowledge Gaps
- •We did not identify any studies that evaluated the effect of any specific hand position on short- or long-term survival after cardiac arrest; only physiological surrogate outcomes have been reported.
- •Imaging studies suggest that there might be important differences in anatomy depending on age, gender, body mass index, presence or absence of chronic heart conditions, and more.
- •Important gaps remain in evaluating how to identify optimal hand placement and/or compression point when using physiological feedback during CPR.
Chest Compression Rate, Chest Compression Depth, and Chest Wall Recoil (BLS 366, BLS 367, BLS 343: ScopRev)
Rationale for Review
The BLS Task Force requested a ScopRev related to chest compression rate, chest compression depth, and chest wall recoil to identify any recent published evidence that provided more information on these chest compression components as discrete entities and to assess whether studies have reported interactions among these chest compression components. Therefore, a ScopRev was undertaken to understand whether the science to date has focused on single chest compression components or interactions among chest compression components and identify the evidence related to the chest compression components to determine whether the body of evidence published since the 2015 CoSTR for BLS indicates the need for a full SysRev of the evidence related to chest compression components.
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Population, Intervention, Comparator, Outcome, Study Design, and Time Frame
- •Population: Adults and children with cardiac arrest
- •Intervention/Comparators: (1) ≥2 chest compression depths measured in millimeters, centimeters, or inches or (2) ≥2 chest compression rates measured in compressions per minute or (3) ≥2 2 measures of chest wall recoil or (4) ≥2 measures of leaning or leaning compared with no leaning
- •Outcomes: Survival to hospital discharge with good neurological outcome and survival to hospital discharge were ranked as critical outcomes. ROSC or survival to a defined time point and physiological measures (eg, blood pressure and ETCO2) were ranked as important outcomes.
- •Study designs: RCTs and nonrandomized studies (non-RCTs, interrupted time series, controlled before-and-after studies, cohort studies) were eligible for inclusion.
- •Time frame: All years and all languages were included as long as there was an English abstract; unpublished studies (eg, conference abstracts, trial protocols) were excluded. The literature search was updated to June 2019.
Summary of Evidence
In addition to the 14 studies identified in the 2015 CoSTR for BLS,
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an additional 8 studies123
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- Sutton R.M.
- Case E.
- Brown S.P.
- et al.
A quantitative analysis of out-of-hospital pediatric and adolescent resuscitation quality—a report from the ROC epistry-cardiac arrest.