Bystander-initiated rescue breathing for out-of-hospital cardiac arrests of noncardiac origin.

BACKGROUND Although chest compression-only cardiopulmonary resuscitation (CPR) is effective for adult out-of-hospital cardiac arrest (OHCA) of cardiac origin, it remains uncertain whether bystander-initiated rescue breathing has an incremental benefit for OHCA of noncardiac origin. METHODS AND RESULTS A nationwide, prospective, population-based, observational study covering the whole population of Japan and involving consecutive OHCA patients with emergency responder resuscitation attempts was conducted from January 2005 through December 2007. The primary outcome was neurologically intact 1-month survival. Multiple logistic regression analysis was used to assess the contribution of bystander-initiated CPR to better neurological outcomes. Among a total of 43 246 bystander-witnessed OHCAs of noncardiac origin, 8878 (20.5%) received chest compression-only CPR, and 7474 (17.3%) received conventional CPR with rescue breathing. The conventional CPR group (1.8%) had a higher rate of better neurological outcome than both the no CPR group (1.4%; odds ratio, 1.58; 95% confidence interval, 1.28 to 1.96) and the compression-only CPR group (1.5%; odds ratio, 1.32; 95% confidence interval, 1.03 to 1.69). However, the compression-only CPR group did not produce better neurological outcome than the no CPR group (odds ratio, 1.19; 95% confidence interval, 0.96 to 1.47). The number of OHCAs needed to treat with conventional CPR versus compression-only CPR to save a life with favorable neurological outcome after OHCA was 290. CONCLUSIONS This nationwide observational study indicates that rescue breathing has an incremental benefit for OHCAs of noncardiac origin, but the impact on the overall survival after OHCA was small.