Moon S, Ryoo HW, Ahn JY, et al. - Researchers examined the effect of bystander CPR on the association between response time interval (RTI) and good neurological outcome. Per their hypothesis, bystander CPR will have positive effect on relationship between RTI and clinical outcome. In this retrospective, observational study performed using Pan-Asian Resuscitation Outcome Study data from January 2009 to December 2016, analysis of a total of 13,245 out-of-hospital cardiac arrest (OHCA) cases was done. Regardless of bystander CPR, median EMS response time intervals of 6 min were reported. Dividing into RTI time range by 3 min, good neurological outcome and survival discharge were only significant in 3 to 6 minutes group in non-bystander CPR group but in bystander CPR group significant RTI time range was 3 to 9 min. With increase in response time interval, they observed slower deterioration of good neurological outcome and survival discharge in cardiac arrest patients with bystander CPR performed. In cases with provision of bystander CPR, relative lengthening in RTI time range showing significant neurological outcome and survival improvement seemed occurring.