Abstract 151: Effect Of Time From Collapse To Prehospital Return Of Spontaneous Circulation On Neurologically Favorable Survival In Patients With Out-of-hospital Cardiac Arrest At Nighttime Versus Daytime

Abstract

Background: Survival with favorable neurological outcomes is one of the goals in patients with out-of-hospital cardiac arrest (OHCA). Although previous studies have shown that a chance of neurologically intact survival was significantly lower at nighttime than at daytime in patients with OHCA, details are uncertain. The aim of this study was to evaluate the effect of time from collapse to prehospital return of spontaneous circulation (ROSC) on neurologically favorable survival in patients with OHCA at nighttime versus daytime. Methods: Using a nationwide OHCA registry database from 2005 to 2020 in Japan, a cohort of 1,902,986 patients with OHCA were retrospectively screened. In the present study, a total of 128,180 patients with witnessed OHCA who achieved prehospital ROSC were included. Nighttime was defined as 6:00 pm through 5:59 am. Neurologically favorable survival was defined as cerebral performance category score of 1 or 2 at 1 month. Results: Patients with witnessed OHCA at nighttime were likely to be younger (70.3±16.0 vs. 72.7±15.3 years, p<0.001) and to have shorter time from collapse to resuscitation (8.1±7.3 vs. 8.6±7.2 min, p<0.001) than those at daytime (6:00 am to 5:59 pm), while time from collapse to ROSC was longer in patients with OHCA at nighttime (18.3±12.7 vs. 17.9±12.2 min, p<0.001). Overall, nighttime OHCA was associated with a lower rate of neurologically favorable survival at 1 months than daytime OHCA (30.9% vs. 31.8%, p<0.001). The negative effect of nighttime OHCA on neurologically favorable survival was observed especially when the time from collapse to prehospital ROSC was within the range of 5 to 10 minutes (Figure). Conclusions: Nighttime rather than daytime OHCA was associated with neurological impaired survival or death at 1 month. The negative effect of nighttime OHCA was pronounced when prehospital ROSC was achieved 5 to 10 minutes after collapse.