Dispatcher instructions for bystander cardiopulmonary resuscitation and neurologically intact survival after bystander-witnessed out-of-hospital cardiac arrests: a nationwide, population-based observational study

Abstract Background The International Liaison Committee on Resuscitation recommends that dispatchers provide instructions to perform compression-only cardiopulmonary resuscitation (CPR) to callers responding to adults with out-of-hospital cardiac arrest (OHCA). This study aimed to determine the optimal dispatcher-assisted CPR (DA-CPR) instructions for OHCA. Methods We analysed the records of 24,947 adult patients (aged ≥ 18 years) who received bystander DA-CPR after bystander-witnessed OHCA. Data were obtained from a prospectively recorded Japanese nationwide Utstein-style database for a 2-year period (2016–2017). Patients were divided into compression-only DA-CPR (n = 22,778) and conventional DA-CPR (with a compression-to-ventilation ratio of 30:2, n = 2169) groups. The primary outcome measure was 1-month neurological intact survival, defined as a cerebral performance category score of 1–2 (CPC 1–2). Results The 1-month CPC 1–2 rate was significantly higher in the conventional DA-CPR group than in the compression-only DA-CPR group (before propensity score (PS) matching, 7.5% [162/2169] versus 5.8% [1309/22778], p