Chest compression or conventional CPR after out of hospital cardiac arrest?BMJ 2011; 342 doi: https://doi.org/10.1136/bmj.d374 (Published 27 January 2011) Cite this as: BMJ 2011;342:d374
- Ian G Jacobs, professor of resuscitation and pre-hospital care
The proportion of people with cardiac arrest who receive bystander cardiopulmonary resuscitation (CPR) before the arrival of an ambulance remains suboptimal. This is disappointing considering the substantial effort over many decades to promote bystander CPR. Reasons for the public not starting resuscitation include fear of infection, fear of litigation, and the complexity of conventional CPR.1 Consequently, it might be possible to improve participation in community CPR by removing the rescue breathing component of conventional CPR. However, such a strategy would be acceptable only if outcomes were at least similar for compression only CPR to those seen for conventional CPR⇓.
In the linked observational study (doi:10.1136/bmj.c7106), Ogawa and colleagues report that one month survival after out of hospital arrest is significantly better with conventional CPR than compression only CPR (adjusted odds ratio 1.17, 95% confidence interval 1.06 to 1.29).2 The authors also found that this benefit was most pronounced in younger patients and when resuscitation was delayed. In particular, conventional CPR had significantly better outcomes for cases of non-cardiac origin when the patient was under 20 years old (4.65, 1.46 to 14.81), and in cases of cardiac origin where resuscitation was delayed by nine to 10 minutes (7.36, 2.07 to 26.20). These better outcomes may be a result of the ventilation and oxygenation provided by conventional CPR correcting global hypoxia, which is more prevalent in the two situations above. These findings contradict previously published studies so it is reasonable to put them into the context of current recommendations.3
A previous observational study found better survival and neurological outcomes with compression only CPR in specific subgroups of patients who were apnoeic, had a shockable rhythm, or in whom CPR was started within four minutes.3 Also, any resuscitation was better than no resuscitation. Other observational studies have shown no difference in survival between conventional and compression only CPR.4 5 6 Some of these findings have been interpreted, possibly erroneously, as both strategies being equally effective. Interestingly, these same studies have also shown better outcomes for conventional CPR in particular subgroups of patients defined by either the patient’s age or the duration of arrest before resuscitation started.4 5 6 7 Several trials of compression only CPR being performed by emergency medical systems personnel have found better outcomes with this strategy, but it is unclear how generalisable these findings are to a public setting.8
The controversy about which type of resuscitation is most effective reflects the difficulty in interpreting evidence in the absence of randomised controlled trials. Observational data are interesting but cannot provide a definitive answer. However, developers of resuscitation guidelines have no choice but to base their recommendations on these methodologically weak data. This position is not uncommon when establishing resuscitation guidelines because undertaking randomised trials in resuscitation is logistically and ethically difficult.
The situation is reflected in the recently published consensus of science statements of the International Liaison Committee on Resuscitation (ILCOR) for conventional versus compression only CPR.9 Consistent with the evidence they have recommended that all people who have had a cardiac arrest should receive chest compressions at the very least. This recognises that any attempt at resuscitation is better than no attempt and focuses on increasing the community CPR participation rate by removing those aspects known to be a barrier to starting CPR, such as rescue breathing. ILCOR further recommends that people trained in conventional CPR and health professionals should perform conventional CPR.
Strategies to increase bystander resuscitation should be encouraged, but not to the abandonment of conventional CPR. Compression only CPR should be viewed as the first resuscitation step, which should be followed as soon as possible by rescue breathing and other basic life support interventions. Controversy will continue until evidence is available from randomised controlled trials, although such studies are unlikely to occur at the community bystander level. What is clear is that any intervention to increase the number of patients receiving CPR, including the use of chest compression only CPR, would improve outcomes after cardiac arrest.
Cite this as: BMJ 2011;342:d374
Competing interests: The author has completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declares: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.
Provenance and peer review: Commissioned; not externally peer reviewed.