Table 4.

Association between resuscitation efforts and cardiac arrest occurring during nighttime hours

	Odds ratio (95 % confidence interval)	P value
Prehospital resuscitation
Call-response interval	0.95 (0.93–0.96)	<0.0001
Bystander CPR	0.85 (0.78–0.93)	0.0002
Advanced airway	1.06 (0.97–1.15)	0.193
Adrenaline	0.92 (0.83–1.03)	0.152
Defibrillation	3.48 (0.81–14.9)	0.093
In-hospital resuscitation
Intubation	0.85 (0.74–0.97)	0.019
Adrenaline	0.99 (0.85–1.16)	0.930
Defibrillation	2.14 (0.93–4.95)	0.074
Blood gas analysis	0.86 (0.75–0.98)	0.020

We limited the analysis of prehospital defibrillation to the patients who had initially shockable rhythm during resuscitation by emergency services personnel, and the analysis of in-hospital defibrillation to patients who had shockable rhythm without return of spontaneous circulation (ROSC) on hospital arrival. Patients with prehospital intubation were excluded from the analysis of in-hospital intubation. P values for prehospital resuscitation were calculated using multivariate logistic regression analysis corrected for age, sex, witness status, call-response interval, bystander cardiopulmonary resuscitation (CPR), and initial shockable rhythm. For the analysis of the in-hospital resuscitation, we further added ROSC on hospital arrival as a covariate and used a generalized estimating equation to account for possible clustering effects of institutions