Chest-compression-only versus standard cardiopulmonary resuscitation: a meta-analysis

Background In out-of-hospital cardiac arrest, dispatcher-assisted chest-compression-only bystander CPR might be superior to standard bystander CPR (chest compression plus rescue ventilation), but trial findings have not shown significantly improved outcomes. We aimed to establish the association of chest-compression-only CPR with survival in patients with out-of-hospital cardiac arrest. Methods Medline and Embase were systematically reviewed for studies published between January, 1985, and August, 2010, in which chest-compression-only bystander CPR was compared with standard bystander CPR for adult patients with out-of-hospital cardiac arrest. In the primary meta-analysis, we included trials in which patients were randomly allocated to receive one of the two CPR techniques, according to dispatcher instructions; and in the secondary meta-analysis, we included observational cohort studies of chest-compression-only CPR. All studies had to supply survival data. The primary outcome was survival to hospital discharge. A fixed-effects model was used for both meta-analyses because of an absence of heterogeneity among the studies (I-2=0%). Findings In the primary meta-analysis, pooled data from three randomised trials showed that chest-compression-only CPR was associated with improved chance of survival compared with standard CPR (14% [211/1500] vs 12% [178/1531]; risk ratio 1.22, 95% CI 1.01-1.46). The absolute increase in survival was 2.4% (95% CI 0.1-4.9), and the number needed to treat was 41 (95% CI 20-1250). In the secondary meta-analysis of seven observational cohort studies, no difference was recorded between the two CPR techniques (8% [223/2731] vs 8% [863/11 152]; risk ratio 0.96, 95% CI 0.83-1.11). Interpretation For adults with out-of-hospital cardiac arrest, instructions to bystanders from emergency medical services dispatch should focus on chest-compression-only CPR.