Continuous chest compression versus interrupted chest compression for cardiopulmonary resuscitation of non‐asphyxial out‐of‐hospital cardiac arrest (2024)

Monitoring Editor: Lei Zhan, Li J Yang, Yu Huang, Qing He, Guan J Liu, and Cochrane Emergency and Critical Care Group

The First People’s Hospital of Shuangliu County, Department of Neurosurgery, ChengduChina, 610041

Affiliated Hospital of Chengdu University, Emergency Department, ChengduSichuanChina, 610081

The Third People's Hospital of Chengdu, Department of Intensive Care Medicine, 82 Qinglong street, ChengduChina, 610031

The Second Affiliated Hospital of Chengdu, Chongqing Medical University, Department of Intensive Care Medicine, ChengduSichuanChina

West China Hospital, Sichuan University, Cochrane China, No. 37, Guo Xue Xiang, ChengduSichuanChina, 610041

Continuous chest compression versus interrupted chest compression for cardiopulmonary resuscitation (CPR) of non‐asphyxial out‐of‐hospital cardiac arrest (OHCA)

Background

A cardiac arrest is when the heart stops pumping blood around the body. It is a major cause of death worldwide. A large number of cardiac arrests occur outside of hospitals. Conventional CPR includes both chest compressions and rescue breathing such as mouth‐to‐mouth resuscitation. This is known as interrupted chest compression with pauses at a fixed ratio for rescue breathing (e.g. 2 breaths: 30 compressions) .

Rescue breathing can be given by mouth‐to‐mouth or by ventilation devices used by ambulance services. Some studies suggest that applying continuous chest compression is critical for an individual's survival and that interrupting the chest compressions for rescue breathing might increase the risk of death. Continuous chest compression CPR may be performed with, or without, rescue breathing. The theory is that chest compression mimics the heart's action of pumping blood around the body and maintains the supply of oxygen and nutrients to important organs such as the brain. Trying to give mouth‐to‐mouth ventilation means interrupting chest compressions which could weaken the action of pumping blood.

We compared the effects of the two treatments when they were given by bystanders at the scene of a non‐asphyxial OHCA and by ambulance crews who arrive later. (A non‐asphyxial arrest does not result from drowning or choking.)

Search date

The evidence is current to February 2017.

Study characteristics

We included four studies; three compared the two approaches to resuscitation when given by untrained bystanders under instruction by telephone. One study compared the two approaches when given by EMS personnel.

The three studies, comparing the approaches given by untrained bystanders, (3737 participants) were all undertaken in urban areas and some included both children and adult OHCA. The, bystanders were all untrained and given telephone instructions from the emergency services.

The fourth study compared approaches given by EMS professionals (23,711 participants); it was undertaken in urban areas and included only adult OHCA.

Key results

When CPR was performed by bystanders, we found that more people survived until discharge from hospital after chest compression alone than they did following interrupted chest compression with pauses at a fixed ratio for rescue breathing (15 compressions to 2 breaths) (14% versus 11.6%). For the outcomes of survival to hospital admission and neurological outcomes, we did not have sufficient data to be certain that either strategy was better. No data was available for adverse effects, quality of life or survival at one‐year.

When CPR was performed by EMS professionals, we found that survival to hospital discharge was slightly lower with continuous chest compressions (100/minute) plus asynchronous rescue breathing (10/minutes) CPR compared with interrupted chest compression plus rescue breathing. Around 9.7% of people lived when they received interrupted chest compression plus rescue breathing compared with 9% of people who received continuous chest compression plus asynchronous rescue breathing.

The number of people who survived to hospital admission was slightly higher in those treated with interrupted chest compression plus rescue breathing compared with continuous chest compression plus asynchronous rescue breathing (25.9% versus 24.6%). There was little or no difference in neurological outcomes. The proportion of people who experienced adverse events was probably similar with 55.4% people treated with interrupted chest compression plus rescue breathing experiencing an adverse event compared with 54.4% in those treated with continuous chest compression asynchronous rescue breathing.

Quality of evidence

For bystander‐provided CPR, the quality of the evidence was high for the outcome of survival to hospital discharge. For survival to hospital admission, one trial provided results and the evidence was of moderate‐quality because of low numbers of people for whom data were available. This was also the case for neurological outcomes.

In the one EMS professional‐provided CPR trial, the quality of the evidence was moderate for the outcome of survival to hospital discharge because the results do not exclude there being little or no difference between the two approaches, and this is also the case for adverse events. For survival to hospital admission there was high‐quality evidence.

The main limitation of the current evidence is that only a few trials have been undertaken, and for some outcomes, not enough data have been generated.

Description of the condition

Cardiac arrest is a condition in which the heart has stopped beating or is not beating efficiently enough to provide circulation to sustain life. It can be confirmed by the absence of a detectable pulse, the patient being unresponsive, or an individual stopping breathing, or breathing abnormally (apnoea, agonal or gasping respirations) (Cummins 1991). Cardiac arrest is a major cause of death in many countries around the world and an important public health problem. In 1998 in the USA, 456,076 deaths were recorded as resulting from sudden cardiac death (Zheng 2001). Approximately 350,000 people in the USA and Canada per year suffer from a cardiac arrest in which resuscitation is attempted (Jones‐Crawford 2007; Nadkarni 2006; Nichol 2008). In Europe, the incidence of emergency medical services (EMS) for treating out‐of‐hospital cardiac arrest is 38 per 100,000 persons per year (ERC 2010).

Cardiac arrest can be subdivided in asphyxial and non asphyxial etiologies. An asphyxia arrest is caused by lack of oxygen in the blood and occurs in drowning and choking victims and in other circ*mstances. A non asphyxial arrest is usually a loss of functioning cardiac electrical activity.

Description of the intervention

Cardiopulmonary resuscitation (CPR) has long been used to treat cardiac arrest. Conventional CPR includes both chest compressions and rescue breathing such as mouth‐to‐mouth breathing; this is denoted interrupted chest compression with pauses at a fixed ratio (either 2 breaths:15 compressions or 2 breaths: 30 compressions) for rescue breathing. Chest compression forces blood from the heart to the arterial system and increases the flow of blood to the coronary arteries, cardiac muscle and brain. In the release phase of the compression, the venous blood flows back to the heart under the force of the negative pressure of the thoracic cavity (Wolcke 2003). Thus, the external compressions lead to the heart 'working again' and so chest compressions provide partial circulatory support. The other important part of CPR is rescue breathing (artifical ventilation) . Rescue breathing can push air into the lungs and improve the blood oxygen saturation. The main form of artificial ventilation in out‐of‐hospital cardiac arrest (OHCA) is mouth‐to‐mouth resuscitation, but rescue breathing can also be provided by any kind of airway device, such as a bag‐valve mask.

CPR for out‐of‐hospital cardiac arrest can be performed using continuous chest compression‐only, or interrupted chest compression plus artificial ventilation (conventional CPR). The difference between continuous chest compression CPR and interrupted (conventional) chest compression CPR, is that in continuous chest compression CPR, rescuers do not interrupt compressions to perform artificial ventilation.

Conventional CPR emphasizes the equal importance of chest compressions and artificial ventilation, whereas compression‐only CPR considers continuous chest compression as being most critical for cardiac arrest victims.

How the intervention might work

CPR provided by bystanders is crucial for cardiac arrest victims, and substantially improves their chances of survival prior to the arrival of EMS personnel. There has been a series of studies focusing on CPR instructions for bystanders; the conclusion is that early initiation of CPR by bystanders leads to better outcomes (AHA 2005; Sayre 2008). But the problem with conventional CPR is that the majority of bystanders (including health professionals) are reluctant to perform mouth‐to‐mouth ventilation, and therefore would not initiate CPR because of the perceived requirement for mouth‐to‐mouth ventilation (Brenner 1993; Brenner 1994; Locke 1995).

There are other reasons that individuals in the USA do not initiate bystander CPR besides the requirement of mouth‐to‐mouth ventilation (Coons 2009). It has been proved that continuity of chest compression is critical for the individual's survival, and interruption of circulation is negatively related to the prognosis of cardiac arrest victims (Bobrow 2008). The longer the compressions are interrupted, the lower the incidence of return of spontaneous circulation (Paradis 1990), and the less likely the defibrillation success (Yu 2002). The 2010 American Heart Association (AHA) guidelines advocate that chest compression is essential for providing blood flow, and all patients should receive it (AHA 2010).

Artificial ventilation as part of CPR, however, may also have adverse effects such as excessive ventilation and interruption of chest compression. Although cardiac arrest can result from hypoxaemia, in patients with circulatory standstill from primary cardiac causes, blood oxygenation is typically normal until the arrest. In the first four minutes of CPR without active ventilation, oxygen saturation was more than 90% in a canine model; even after 10 minutes, the oxygen saturation was above 70% (Chandra 1994). Noc et al, investigated a domestic pig model of cardiac arrest and found that the passive ventilation (precordial compression and spontaneous gasping) volume was more than 5 L in the fifth minute of ventricular fibrillation (Noc 1995). Moreover, about 55% of out‐of‐hospital cardiac arrests occur with spontaneous gasping, which can provide the patient with some ventilation (Clark 1992). So it appears to be more important to initially restore blood circulation than push air into the lungs. As a consequence, the key change of the 2010 AHA guideline is from a conventional airway‐breathing‐circulation (A‐B‐C) sequence to circulation‐airway‐breathing (C‐A‐B), and untrained lay rescuers in particular are encouraged to do compression‐only CPR (AHA 2010). These guidelines recommend initiating chest compressions as being most important (AHA 2010). Moreover, the effect of ventilation is related to the skill or training level of the provider. It is difficult and time consuming to provide a bystander with instructions to perform ventilation or rescue breaths during CPR. However, it is fairly simple to provide a bystander with instructions for chest compression. Some studies conclude that survival with compression‐only CPR initiated by bystanders is similar to, or even better than, that provided by compression and ventilation CPR. This has been demonstrated in several studies reporting improved survival or neurological function outcomes (Bobrow 2010; Hallstrom 2000; SOS‐KANTO Group 2007; Svensson 2010; Tang 1994).

The new CPR guidelines encourage bystanders to provide compression‐only CPR before the arrival of emergency medical service personnel. The American and European guidelines recommend continuous chest compression‐only CPR in telephone advice to bystanders, especially when the rescuer is either unable or unwilling to perform rescue breaths (AHA 2010; ERC 2010). Continuous chest compression CPR performed by emergency medical service providers reduce the interruption of compressions, which is associated with higher rates of survival than interrupted compressions (Bobrow 2008).

Why it is important to do this review

A flawed conclusion frequently encountered is that everybody should perform continuous chest compression‐only CPR, a fact that is not well supported by the evidence because solid evidence is available only for a specific situation. Specifically, the effect of continuous chest compression‐only CPR may be different if performed by lay bystanders who obtain telephone advice as compared to professional CPR providers who are well trained and equipped. For bystanders, the willingness to perform CPR is associated with fear of acquiring infectious diseases by performing mouth‐to‐mouth ventilation (Becker 1997). Less than 30% of all out‐of‐hospital cardiac arrests receive bystander CPR (Eckstein 2005), which could be related to an unwillingness to perform mouth‐to‐mouth ventilation. Effective instructions for bystanders by emergency dispatchers that omit instructions for mouth‐to‐mouth ventilation are a possible point of action to increase the rate of bystander CPR. Many studies on telephone instructions for bystander CPR have recently been published (Bobrow 2010; Svensson 2010; SOS‐KANTO Group 2007). Although there have been studies supporting the effects of continuous chest compression‐only CPR, others have shown that worse outcomes were obtained by the use of continuous chest compression‐only CPR compared to conventional interrupted chest compression with pauses for breathing CPR (Ogawa 2011; Travers 2010). Differences in study design and quality make the interpretation challenging.

For professional CPR providers, however, hyperventilation during CPR was identified as a relevant issue (Aufderheide 2004). Continuous chest compression‐only CPR may accordingly have a very different meaning here. Moreover, even if continuous chest compression‐only CPR proves effective, details on continuous chest compression‐only CPR performance, teaching and communication remain to be elucidated. And for professional CPR providers, if they could get an AED nearby, the time of the AED arrival would directly affect the outcome of the victim.

The first review on continuous chest compression‐only CPR was published in the Lancet (Hüpfl 2010). We consider that a Cochrane Review will help us to further examine the effectiveness of continuous chest compression‐only CPR versus conventional interrupted chest compression with pauses for breathing CPR.

Criteria for considering studies for this review

Search methods for identification of studies

Data collection and analysis

Description of studies

See: Figure 1; Characteristics of included studies; Characteristics of excluded studies.

Risk of bias in included studies

The assessment of risk of bias is shown in the Characteristics of included studies table and in Figure 2.

Effects of interventions

See: Table 1; Table 2

Summary of main results

We identified four trials which evaluated the effect of continuous chest compression CPR versus conventional (interrupted chest compression) CPR for OHCA (Hallstrom 2000; Nichol 2015; Rea 2010; Svensson 2010). A total of 26,742 participants were enrolled for analysis in the four trials. Three trials were RCTs, in which CPR was delivered by bystanders (Hallstrom 2000; Rea 2010; Svensson 2010), and one trial was a cluster‐RCT, in which CPR was delivered by emergency medical service providers (Nichol 2015). All trials reported the primary outcomes of survival to hospital discharge and survival to hospital admission. Loss to follow‐up in all trials was within an acceptable range.

Pooled data from three trials of bystander‐initiated CPR showed an increase in the number of people surviving to hospital discharge from 11.6% to 14% when continuous chest compression‐only CPR was used compared with interrupted chest compression plus ventilation (Hallstrom 2000; Rea 2010; Svensson 2010). Only one trial reported the outcome of survival to hospital admission (Hallstrom 2000), and one trial reported neurological outcomes at hospital discharge (Rea 2010); we found no significant differences between the two treatment groups (see: Analysis 1.2; Analysis 1.3).

Only one trial involved CPR performed by emergency medical service providers (Nichol 2015). Nichol 2015 reported that continuous chest compressions plus asynchronous rescue breathing did not result in significantly higher rates of survival compared to interrupted chest compressions plus ventilation. The result showed a statistically significant difference between the two groups in survival to hospital admission (risk difference (RD) ‐1.3, 95% confidence interval (CI) ‐2.4% to ‐0.2%). There were no significant differences between the two treatment groups in neurological outcomes at hospital discharge (RD 0.04, 95% CI 0.00% to 0.08%) and the rate of return of spontaneous circulation (RD ‐1.1, 95% CI ‐2.4% to 0.2%). Nichol 2015 also showed that there was no significant difference between the two treatment groups in the rates of individual adverse events.

Overall completeness and applicability of evidence

All four trials included out‐of‐hospital cardiac arrest, but excluded asphyxial arrests (Hallstrom 2000; Rea 2010; Svensson 2010; Nichol 2015). Furthermore, the four trials included the common first cardiac rhythm of the participants who suffered cardiac arrest, such as ventricular fibrillation, asystole, pulseless electrical activity and ventricular tachycardia etc. We identified no data on return to spontaneous rhythm or long‐term outcomes following bystander‐initiated CPR (Table 1). Limited information was reported on adverse events.

Although the advanced life support methods were performed according to different guidelines respectively, we felt that such clinical heterogeneity was negligible because no evidence has been found to demonstrate that there was any effect of different guidelines on the clinical therapy. All four trials in our review were performed in urban settings. The mean intervals from call to emergency medical service arrival varied from 4.0 to 10.3 minutes in the four trials (Hallstrom 2000; Nichol 2015; Rea 2010; Svensson 2010). Unfortunately, we do not have enough data to perform a posthoc analysis to assess the association between the time interval of emergency medical service arrival and outcomes.

Quality of the evidence

We did not downgrade the quality of the evidence due to risk of bias for survival to hospital discharge because the objective nature of the outcome means that it is unlikely to be influenced by the unblinded nature of the interventions for bystander administered CPR. We downgraded the quality of the evidence due to imprecision for two outcomes following bystander administered CPR in Table 1 where there were a low number of events and small sample sizes. Although the lower limit of the confidence interval for risk ratio for the outcome of survival to hospital discharge following bystander CPR is close to 1, the high rate of mortality in this population overall means that our confidence in the result is high. For the comparison of different CPR approaches administered by emergency medical staff, we downgraded the quality of evidence for survival to discharge and adverse effects due to imprecision. The confidence intervals were wide enough to justify the decision to adopt either resuscitation strategy (Table 2). We did not consider the studies or outcomes to be indirect and there was no obvious evidence of publication bias in this review, so we did not downgrade the quality of the evidence for any outcomes due to these limitations.

Potential biases in the review process

Whilst our searches are comprehensive, there may be completed, unregistered studies that our searches have not been able to identify. Our attempts to examine the effect of age on survival outcomes were unsuccessful, and this remains an uncertainty that future research should investigate. For most outcomes from the Nichol 2015 trial, we have used data for the ITT population in preference to that available for the safety population. Whilst results obtained with these populations were similar for adverse event data, the effect on survival attenuated slightly from a difference in risk of 0.7% to 0.2%.

Agreements and disagreements with other studies or reviews

When CPR was performed by bystanders, three observational studies addressed similar objectives to our review (Bohm 2007; Crane 2008; Ong 2008). Theobservational studies showed that there were no significant differences in the outcomes between the two treatment groups. The lay bystanders made the decision as to whether to give mouth‐to‐mouth ventilation or not, and perform CPR, without the dispatchers' assistance.

However, in another prospective cohort study conducted in Arizona (Bobrow 2010), there was a CPR training programme called the Save Hearts in Arizona Registry and Education (SHARE) programme. The bystanders in that study, who called emergency medical service when an out‐of‐hospital cardiac arrest had taken place, were mostly trained in the continuous CPR technique. The results of this study show that layperson compression‐only CPR is associated with an increased survival rate compared with conventional CPR, which is consistent with our pooled results. The result of this study (Bobrow 2010),was different to our review when CPR was performed by emergency medical service providers. The quality of compression cannot be monitored when CPR was performed by bystanders, we presume that even the bystanders were trained in CPR training program, the quality of compression was poorer than that performed by professional providers. The technique of COCPR was easer than conventional CPR, so we presume that when CPR was performed by bystanders which were trained in CPR program, the quality of compression in COCPR would be better than that in conventional CPR. But when CPR was performed by professional providers, the quality of compress may be the same in most time whatever in COCPR or conventional CPR. This may be the reason that the result of Bobrow 2010 was different from our review when CPR was performed by professional providers, but the same when CPR was performed by bystanders.

In our review, there were two subgroups: bystander‐provided CPR; and professional‐provided CPR. The results of the two subgroups in our review were different. We suspect that a reason for the difference was because of differences in the quality of the compression.

The Hüpfl 2010 review performed a meta‐analysis of continuous chest compression‐only CPR versus standard CPR for out‐of‐hospital cardiac arrest, and included the same three RCTs as our Cochrane Review. As expected, the pooled data showed similar findings to our own.

Implications for practice

According to our pooled results, when CPR was performed by untrained bystanders who were assisted by receiving telephone instruction from emergency services, continuous chest compression‐only CPR led to more people surviving to hospital discharge compared with interrupted chest compression plus artificial ventilation CPR for non asphyxial OHCA. The difference in survival to hospital discharge is about 25 more people per 1000 following bystander administered continuous chest compression. When CPR was performed by professional providers, continuous chest compressions with asynchronous rescue breathing did not result in higher rates of survival compared with interrupted chest compressions plus rescue breathing CPR for non asphyxial OHCA. The results indicate slightly lower rates of survival to admission or discharge, favourable neurological outcome and return of spontaneous circulation observed following continuous chest compression. Adverse effects were slightly lower with continuous chest compression.

Implications for research

Our review has identified moderate or high quality evidence for short‐term survival outcomes in bystander‐initiated resuscitation, and high quality evidence for short‐term survival outcomes in professionally provided resuscitation. Future studies should include evaluations of adverse effects, and of longer‐term neurological outcomes and quality of life. The influence of automated external defibrillator (AED) availability and AED use on the effect of continuous chest compression CPR needs to be examined. Likewise, it remains unclear whether the concept of continuous chest compression CPR is appropriate for paediatric cardiac arrest. One ongoing study is addressing the question of feasibility in a smaller sample size to the studies we have identified in this review (NCT02401633).

We would like to thank Harald Herkner (content and statistical editor), Nathan Pace (Co‐ordinating Editor), Jane Cracknell (Managing Editor), Janne Vendt (Information Specialist), Gordon A Ewy, Sandra M Marini (peer reviewers), Janet Wale (consumer editor), Liz Bickerdike (CEU editor), Toby Lasserson (Senior CEU editor), Clare Dooley and Elizabeth Royle (Copy Edit Support) for their help and editorial advice during the preparation of this Cochrane Review.

We would also like to thank the following people for their help and advice during the preparation of the protocol for the review (Yang 2012): Jane Cracknell, Karen Hovhannisyan, Yaxin Yu, Marialena Trivella, Sandra Marini, Gordon Ewy, Marc Afilalo, Ian Jacobs Clare Jeffrey and the Cochrane Prehospital and Emergency Health Field.

Comparison 1

Comparison 2

Characteristics of included studies [ordered by study ID]

Characteristics of excluded studies [ordered by study ID]

Characteristics of ongoing studies [ordered by study ID]

Hallstrom 2000 {published data only}

• Hallstrom A, Cobb L, Johnson E, Copass M. Cardiopulmonary resuscitation by chest compression alone or with mouth‐to‐mouth ventilation. New England Journal of Medicine 2000;25:1546‐53. [PUBMED: 10824072] [PubMed] [Google Scholar]

Nichol 2015 {published data only}

• Nichol G, Leroux B, Wang H, Callaway CW, Sopko G, Weisfeldt M, et al. Trial of continuous or interrupted chest compressions during CPR. New England Journal of Medicine 2015;373(23):2203‐14. [PUBMED: 26550795] [PubMed] [Google Scholar]

Rea 2010 {published data only}

• Rea TD, Fahrenbruch C, Culley L, Donohoe RT, Hambly C, Innes J, et al. CPR with chest compression alone or with rescue breathing. New England Journal of Medicine 2010;363:423‐33. [PUBMED: 20818863] [PubMed] [Google Scholar]

Svensson 2010 {published data only}

• Svensson L, Bohm K, Castrèn M, Pettersson H, Engerström L, Herlitz J, et al. Compression‐only CPR or standard CPR in out‐of‐hospital cardiac arrest. New England Journal of Medicine 2010;363:434‐42. [PUBMED: 20818864] [PubMed] [Google Scholar]

Bobrow 2010 {published data only}

• Bobrow BJ, Spaite DW, Berg RA, Stolz U, Sanders AB, Kern KB, et al. Chest compression‐only CPR by lay rescuers and survival from out‐of‐hospital cardiac arrest. JAMA 2010;304:1447‐54. [PubMe: 20924010 ] [PubMed] [Google Scholar]

Bohm 2007 {published data only}

• Bohm K, Rosenqvist M, Herlitz J, Hollenberg J, Svensson L. Survival is similar after standard treatment and chest compression only in out‐of‐hospital bystander cardiopulmonary resuscitation. Circulation 2007;116(25):2908‐12. [PUBMED: 18071077] [PubMed] [Google Scholar]

Cabrini 2010 {published data only}

• Cabrini L, Biondi‐Zoccai G, Landoni G, Greco M, Vinciguerra F, Greco T, et al. Bystander‐initiated chest compression‐only CPR is better than standard CPR in out‐of‐hospital cardiac arrest. HSR Proceedings in Intensive Care and Cardiovascular Anesthesia 2010;2:279‐85. [PUBMED: 23439400] [PMC free article] [PubMed] [Google Scholar]

Crane 2008 {published data only}

• Crane SA, Callaway CW, Milbrandt EB, Huang DT. Rethinking bystander CPR for out‐of‐hospital cardiac arrest. Critical Care 2008;12:302. [PUBMED: 18341712] [PMC free article] [PubMed] [Google Scholar]

Hüpfl 2010 {published data only}

• Hüpfl M, Selig HF, Nagele P. Chest‐compression‐only versus standard cardiopulmonary resuscitation: a meta‐analysis. Lancet 2010;376:1552‐7. [PUBMED: 20951422] [PMC free article] [PubMed] [Google Scholar]

Kitamura 2010 {published data only}

• Kitamura T, Iwami T, Kawamura T, Nagao K, Tanaka H, Nadkarni VM, et al. Conventional and chest‐compression‐only cardiopulmonary resuscitation by bystanders for children who have out‐of‐hospital cardiac arrests: a prospective, nationwide, population‐based cohort study. Lancet 2010;375:1347‐54. [PUBMED: 20202679] [PubMed] [Google Scholar]

Ong 2008 {published data only}

• Ong ME, Ng FS, Anushia P, Tham LP, Leong BS, Ong VY, et al. Comparison of chest compression only and standard cardiopulmonary resuscitation for out‐of‐hospital cardiac arrest in Singapore. Resuscitation 2008;78:119‐26. [PUBMED: 18502559] [PubMed] [Google Scholar]

Sayre 2008 {published data only}

• Sayre MR, Berg RA, Cave DM, Page RL, Potts J, White RD. 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;117:2162‐7. [PUBMED: 18378619] [PubMed] [Google Scholar]

Swor 2003 {published data only}

• Swor R, Compton S, Vining F, Ososky Farr L, Kokko S, Pascual R, et al. A randomized controlled trial of chest compression only CPR for older adults ‐ a pilot study. Resuscitation 2003;58:177‐85. [PUBMED: 12909380] [PubMed] [Google Scholar]

NCT02401633 {unpublished data only}

• NCT02401633. Compression‐only CPR versus standard‐CPR ‐ the run‐in phase [A randomized trial comparing the effect of a simplified form of cardiopulmonary resuscitation (CPR) consisting of only chest compressions compared to CPR with compressions and rescue breaths ‐ the run‐in phase]. clinicaltrials.gov/ct2/show/NCT02401633 (first received 7 March 2015).

AHA 2000

• American Heart Association. Part 1: Introduction to the International Guidelines 2000 for CPR and ECC: a consensus on science. Circulation 2000;102((8 Suppl)):1‐11. [PUBMED: 10964901] [PubMed] [Google Scholar]

AHA 2005

• ECC Committee, Subcommittees and Task Forces of the American Heart Association. 2005 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation 2005;112 Suppl((24 Suppl)):IV1‐203. [PUBMED: 16314375] [PubMed] [Google Scholar]

AHA 2010

• Travers AH, Rea TD, Bobrow BJ, Edelson DP, Berg RA, Sayre MR, et al. Part 4: CPR overview: 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation 2010;122((18 Suppl 3)):S676‐84. [PUBMED: 20956220] [PubMed] [Google Scholar]

Aufderheide 2004

• Aufderheide TP, Sigurdsson G, Pirrallo RG, Yannopoulos D, McKnite S, Briesen C. Hyperventilation‐induced hypotension during cardiopulmonary resuscitation. Circulation 2004;109:1960‐5. [PUBMED: 15066941] [PubMed] [Google Scholar]

Becker 1997

• Becker LB, Berg RA, Pepe PE, Idris AH, AufderheideTP, Barnes TA. A reappraisal of mouth‐to‐mouth ventilation during bystander‐initiated cardiopulmonary resuscitation. A statement for healthcare professionals from the Ventilation Working Group of the Basic Life Support and Pediatric Life Support Subcommittees, American Heart Association. Circulation 1997;96:2102‐12. [PUBMED: 9323122] [PubMed] [Google Scholar]

Bobrow 2008

• Bobrow BJ, Clark LL, Ewy GA, Chikani V, Sanders AB, Berg RA. Minimally interrupted cardiac resuscitation by emergency medical services for out‐of‐hospital cardiac arrest. JAMA 2008;299:1158‐65. [PUBMED: 18334691] [PubMed] [Google Scholar]

Brenner 1993

• Brenner BE, Kauffman J. Reluctance of internists and medical nurses to perform mouth‐to‐mouth resuscitation. Archives of Internal Medicine 1993;153:1763‐9. [PUBMED: 8333813] [PubMed] [Google Scholar]

Brenner 1994

• Brenner B, Stark B, Kauffman J. The reluctance of house staff to perform mouth‐to‐mouth resuscitation in the inpatient setting: what are the considerations?. Resuscitation 1994;28:185‐93. [PUBMED: 7740188] [PubMed] [Google Scholar]

Chandra 1994

• Chandra NC, Gruben KG, Tsitlik JE, Brower R, Guerci AD, Halperin HH. Observations of ventilation during resuscitation in a canine model. Circulation 1994;304:1447‐54. [PUBMED: 7994856] [PubMed] [Google Scholar]

Clark 1992

• Clark JJ, Larsen MP, Culley LL, Graves JR, Eisenberg, MS. Incidence of agonal respirations in sudden cardiac arrest. Annals of Emergency Medicine 1992;21:1464‐7. [PUBMED: 1443844] [PubMed] [Google Scholar]

Coons 2009

• Coons SJ, Guy MC. Performing bystander CPR for sudden cardiac arrest: behavioral intentions among the general adult population in Arizona. Resuscitation 2009;80:334‐40. [PUBMED: 19157675] [PubMed] [Google Scholar]

Cummins 1991

• Cummins RO, Chamberlain DA, Abramson NS, Allen M, Baskett PJ, Becker L. Recommended guidelines for uniform reporting of data from out‐of‐hospital cardiac arrest: the Utstein Style. Circulation 1991;84:960‐75. [PUBMED: 1860248] [PubMed] [Google Scholar]

Eckstein 2005

• Eckstein M, Stratton SJ, Chan LS. Cardiac Arrest Resuscitation Evaluation in Los Angeles: CARE‐LA. Annals of Emergency Medicine 2005;45:504‐9. [PUBMED: 15855947] [PubMed] [Google Scholar]

ERC 2010

• European Resuscitation Council. European Resuscitation Council guidelines for resuscitation 2010 section 1. Executive summary. Resuscitation 2010;81:1219‐76. [PUBMED: 20956052] [PubMed] [Google Scholar]

Guyatt 2008

• Guyatt GH, Oxman AD, Vist GE, Kunz, R, Falck‐Ytter Y, Alonso‐Coello P. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ 2008;336:924‐6. [PUBMED: 2335261] [PMC free article] [PubMed] [Google Scholar]

Handley 2005

• Handley AJ, Koster R, Monsieurs K, Perkins GD, Davies S, Bossaert L, European Resuscitation Council. European Resuscitation Council guidelines for resuscitation 2005. Section 2. Adult basic life support and use of automated external defibrillators. Resuscitation 2005;67 Suppl 1:S7‐23. [PUBMED: 16321717] [PubMed] [Google Scholar]

Higgins 2011

• Higgins JP, Green S, editor(s). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011). The Cochrane Collaboration, 2011. Available from handbook.cochrane.org.

Jones‐Crawford 2007

• Jones‐Crawford JL, Parish DC, Smith BE, Dane FC. Resuscitation in the hospital: circadian variation of cardiopulmonary arrest. American Journal of Medcine 2007;120:158–64. [PUBMED: 17275457] [PubMed] [Google Scholar]

Jüni 2001

• Jüni P, Altman D, Egger M. Systematic reviews in healthcare: assessing the quality of controlled clinical trials. BMJ 2001;323:42‐6. [PUBMED: 11440947] [PMC free article] [PubMed] [Google Scholar]

Locke 1995

• Locke CJ, Berg RA, Sanders AB, Davis MF, Milander MM, Kern KB, et al. Bystander cardiopulmonary resuscitation. Concerns about mouth‐to‐mouth contact. Archives of Internal Medicine 1995;155:938‐43. [PUBMED: 7726702] [PubMed] [Google Scholar]

Nadkarni 2006

• Nadkarni VM, Larkin GL, Peberdy MA, Carey SM, Kaye W, Mancini ME, et al. First documented rhythm and clinical outcome from in‐hospital cardiac arrest among children and adults. JAMA 2006;295:50‐7. [PUBMED: 16391216] [PubMed] [Google Scholar]

Nichol 2008

• Nichol G, Thomas E, Callaway CW, Hedges J, Powell JL, Aufderheide TP, et al. Regional variation in out‐of‐hospital cardiac arrest incidence and outcome. JAMA 2008;300:1423‐32. [PUBMED: 18812533] [PMC free article] [PubMed] [Google Scholar]

Noc 1995

• Noc M, Weil MH, Tang W, Turner T, f*ckui M. Mechanical ventilation may not be essential for initial cardiopulmonary resuscitation. Chest 1995;108:821‐7. [PUBMED: 7656640] [PubMed] [Google Scholar]

Ogawa 2011

• Ogawa T, Akahane M, Koike S, Tanabe S, Mizoguchi T, Imamura T. Outcomes of chest compression only CPR versus conventional CPR conducted by lay people in patients with out of hospital cardiopulmonary arrest witnessed by bystanders: nationwide population based observational study. BMJ 2011;342:c7106. [PUBMED: 21273279] [PubMed] [Google Scholar]

Paradis 1990

• Paradis NA, Martin GB, Rivers EP, Goetting MG, Appleton TJ, Feingold M. Coronary perfusion pressure and the return of spontaneous circulation in human cardiopulmonary resuscitation. JAMA 1990;263:1106‐13. [PUBMED: 2386557] [PubMed] [Google Scholar]

RevMan 2014 [Computer program]

• Nordic Cochrane Centre, The Cochrane Collaboration. Review Manager 5 (RevMan 5). Version 5.3. Copenhagen: Nordic Cochrane Centre, The Cochrane Collaboration, 2014.

Rucker 2008

• Rucker G, Schwarzer G, Carpenter J. Arcsine test for publication bias in meta‐analyses with binary outcomes. Statistics in Medicine 2008;27:746‐63. [PUBMED: 17592831] [PubMed] [Google Scholar]

SOS‐KANTO Group 2007

• SOS‐KANTO Group. Cardiopulmonary resuscitation by bystanders with chest compression only (SOS‐KANTO): an observational study. Lancet 2007;369:920‐6. [PUBMED: 17368153] [PubMed] [Google Scholar]

Tang 1994

• Tang W, Weil MH, Sun S, Kette D, Kette F, Gazmuri RJ. Cardiopulmonary resuscitation by precordial compression but without mechanical ventilation. American Journal of Respiratory and Critical Care Medicine 1994;150:1709‐13. [PUBMED: 7952638] [PubMed] [Google Scholar]

Travers 2010

• Travers S, Dubourg O, Bon O, Banville IL, Jost D, VerretC. Chest compressions only or full CPR for out‐of‐hospital cardiac arrest? Unexpected outcomes from the DEFI2005 trial. Resuscitation 2010;81:S9. [DOI: 10.1016/j.resuscitation.2010.09.048] [CrossRef] [Google Scholar]

Wolcke 2003

• Wolcke BB, Mauer DK, Schoefmann MF, TeichmannH, Provo TA, Lindner KH. Comparison of standard cardiopulmonary resuscitation versus the combination of active compression‐decompression cardiopulmonary resuscitation and an inspiratory impedance threshold device for out‐of‐hospital cardiac arrest. Circulation 2003;108:2201‐1. [PUBMED: 14568898] [PubMed] [Google Scholar]

Yu 2002

• Yu T, Weil MH, Tang W, Sun S, Klouche K, Povoas H. Adverse outcomes of interrupted precordial compression during automated defibrillation. Circulation 2002;106:368‐72. [PUBMED: 12119255] [PubMed] [Google Scholar]

Zheng 2001

• Zheng ZJ, Janet BC, Wayne HG, George AM. Sudden cardiac death in the United States, 1989 to 1998. Circulation 2001;104:2158‐63. [PubMed] [Google Scholar]

Yang 2012

• Yang LJ, He Q, Huang Y, Liu GJ. Chest compression alone versus chest compression plus artificial ventilation for out‐of‐hospital cardiac arrest. Cochrane Database of Systematic Reviews 2012, Issue 10. [DOI: 10.1002/14651858.CD010134] [CrossRef] [Google Scholar]