Characteristics and outcomes of out-of-hospital sudden cardiac arrest according to the time of occurrence

Purpose: The impact of time of occurrence has been extensively evaluated for in-hospital cardiac arrests but less for Out-of-Hospital Cardiac Arrests (OHCA). We assessed the impact of the time of occurrence on the characteristics and prognosis of OHCA. Methods: Using data from the Paris Sudden Cardiac Death Expertise Center prospective study that includes all OHCA in the Paris Area, we compared characteristics and outcomes of off-hours OHCA (nights and days off) to regular-hours OHCA between 2011 and 2014. Results: Among a total of 9834 OHCA (70.0 +/- 17 years old, 62.1% males), off-hours OHCA accounted for 63.4%. Although bystanders were more often present (74.4 vs. 72.1%, P = 0.01), rates of bystander CPR (46.7 vs. 50.6%, P = 0.001) and AED use (1.0 vs. 1.9%, P = 0.01) were lower during off-hours. While EMS arrival delays were similar, patients were less often in shockable rhythm (16.3 vs. 19.1%, P < 0.0001), and return of spontaneous circulation was less frequent (27.5 vs. 31.1%, P < 0.0001). There was no difference in rates of targeted temperature control (54.8 vs. 54.7%, P = 0.75), coronary angiography (57.3 vs. 58.2%, P = 0.68) and angioplasty use (32.2 vs. 35.6%, P = 0.22). Survival at hospital discharge was lower (4.7 vs. 6.5%, P < 0.0001) during off-hours. After adjusting for potential confounders, time of occurrence was not associated with worse outcome (OR 0.85, 95% CI 0.69-1.06, P = 0.15), and bystander-initiated CPR, shockable initial rhythm and AED use were the main survival predictors (P < 0.0001). Conclusion: Off-hours OHCA have a 30% lower survival rate, mainly due to differences in initial management (bystander CPR and AED use), illustrating the need to improve bystanders' responsiveness in all circumstances. (C) 2017 Elsevier B.V. All rights reserved.