Funada A, et al. - Researchers used the all-Japan out-of-hospital cardiac arrest (OHCA) registry to determine the time-dependent efficacy of prehospital epinephrine use on post-arrest neurological outcome in 118,396 bystander-witnessed OHCA patients with non-shockable rhythm. This study did not include those who attained prehospital return of spontaneous circulation without prehospital epinephrine administration. Neurologically intact survival in bystander-witnessed OHCA patients with non-shockable rhythm could be improved if prehospital epinephrine is administered ≤ 19 minutes from CPR initiation by EMS providers in cases when prehospital CPR duration (from CPR initiation by EMS providers to hospital arrival) was estimated to be ≥ 11 min.