Effectiveness of different compression-to-ventilation methods for cardiopulmonary resuscitation: A systematic review

Aim: To compare the effectiveness of different compression-to-ventilation methods during cardiopulmonary resuscitation (CPR) in patients with cardiac arrest. Methods: We searched MEDLINE and Cochrane Central Register of Controlled Trials from inception until January 2016. We included experimental, quasi-experimental, and observational studies that compared different chest compression-to-ventilation ratios during CPR for all patients and assessed at least one of the following outcomes: favourable neurological outcomes, survival, return of spontaneous circulation (ROSC), and quality of life. Two reviewers independently screened literature search results, abstracted data, and appraised the risk of bias. Random-effects meta-analyses were conducted separately for randomised and non-randomised studies, as well as study characteristics, such as CPR provider. Results: After screening 5,703 titles and abstracts and 229 full-text articles, we included 41 studies, of which 13 were companion reports. For adults receiving bystander or dispatcherinstructed CPR, no significant differences were observed across all comparisons and outcomes. Significantly less adults receiving bystander-initiated or plus dispatcher-instructed compressiononly CPR experienced favourable neurological outcomes, survival, and ROSC compared to CPR 30:2 (compression-to-ventilation) in un-adjusted analyses in a large cohort study. Evidence from emergency medical service (EMS) CPR providers showed significantly more adults receiving CPR 30:2 experiencing improved favourable neurological outcomes and survival versus those receiving CPR 15:2. Significantly more children receiving CPR 15:2 or 30:2 experienced favourable neurological outcomes, survival, and greater ROSC compared to compression-only CPR. However, for children <1 years of age, no significant differences were observed between CPR 15:2 or 30:2 and compression-only CPR. Conclusions: Our results demonstrated that for adults CPR 30:2 is associated with better survival and favourable neurological outcomes when compared to CPR 15:2. For children, more patients receiving CPR with either 15:2 or 30:2 compression-to ventilation ratio experienced 5 favourable neurological function, survival, and ROSC when compared to CO-CPR for children of all ages, but for children