Effect of night-time onset on neurologically favourable survival between patients with and without bystander cardiopulmonary resuscitation.

Abstract

Background: Patients with out-of-hospital cardiac arrest (OHCA) during the night tend to have worse outcomes than those with OHCA during the day. One possible explanation for poorer outcomes in patients with night-time onset is the lower quality of bystander cardiopulmonary resuscitation (CPR), although the exact cause has not been fully clarified. This study evaluated the differences between day and night-time-OHCA onset on neurologically favourable survival for patients with and without bystander CPR.

Methods: A cohort of 118,822 patients with witnessed OHCA and prehospital return of spontaneous circulation was obtained from a nationwide OHCA registry database in Japan. The primary endpoint was neurologically favourable survival at 1 month. We also investigated the impact of night-time bystander CPR presence or absence as a sub-analysis.

Results: The neurologically favourable survival rate was significantly lower for patients with night-time than those with daytime OHCA onset (30.7 % vs. 31.8 %, p < 0.001). The multivariable analysis determined night-time OHCA onset was a significant negative factor associated with neurologically favourable survival at 1-month [odds ratio (OR) 0.95; 95 % confidence interval (CI) 0.92-0.98, p = 0.002]. This negative effect of night-time onset compared to daytime was more pronounced for patients with bystander CPR from a citizen (OR 0.91; 95 % CI 0.87-0.95, p < 0.001). In contrast, this negative effect was attenuated in patients without bystander CPR (OR 1.00; 95 % CI 0.95-1.04, p = 0.836).

Conclusion: These results suggest that the insufficient quality of bystander CPR may be one of the causes for the negative impact of night-time OHCA compared to daytime on patients.