Age-Specific Differences in the Duration of Prehospital Cardiopulmonary Resuscitation Administered by Emergency Medical Service Providers Necessary to Achieve Favorable Neurological Outcome After Out-of-Hospital Cardiac Arrest.

Background:The appropriate duration of prehospital cardiopulmonary resuscitation (CPR)administered by emergency medical service (EMS) providers for patients with out-of-hospital cardiac arrest (OHCA) necessary to achieve 1-month survival with favorable neurological outcome (Cerebral Performance Category 1 or 2, CPC 1–2) is unclear and could differ by age. Methods and Results:We analyzed the records of 35,709 adult OHCA patients with return of spontaneous circulation (ROSC) before hospital arrival in a prospectively recorded Japanese registry between 2011 and 2014. The CPR duration was defined as the time from CPR initiation by EMS providers to prehospital ROSC. The rate of 1-month CPC 1–2 was 21.4% (7,650/35,709). The CPR duration was independently and inversely associated with 1-month CPC 1–2 (adjusted odds ratio, 0.93 per 1-min increment; 95% confidence interval, 0.93–0.94). The CPR duration increased with age (P<0.001). However, the CPR duration beyond which the proportion of OHCA patients with 1-month CPC 1–2 decreased to <1% declined with age: 28 min for patients aged 18–64 years, 25 min for 65–74 years, 23 min for 75–84 years, 20 min for 85–94 years, and 18 min for ≥95 years. Conclusions:In patients who achieved prehospital ROSC after OHCA, the duration of CPR administered by EMS providers necessary to achieve 1-month CPC 1–2 varied by age.