Differences in durations, adverse events, and outcomes of in-hospital cardiopulmonary resuscitation between day-time and night-time: An observational cohort study

Background: Although patients with out-of-hospital cardiac arrest (OHCA) have a lower survival rate during night-time than during day-time, the cause of this difference remains unclear. We aimed to assess CPR parameters according to time period based on in-hospital cardiopulmonary resuscitation (IHCPR) duration and the frequency of iatrogenic chest injuries among OHCA patients.

Methods: This two-centre observational cohort study evaluated non-traumatic OHCA patients who were transferred between 2013-2016. These patients were categorised according to whether they received day-time treatment (07:00-22:59) or night-time treatment (23:00-06:59). Differences in IHCPR duration, CPR-related chest injuries, return of spontaneous circulation, and survivals to emergency department and hospital discharge were compared using a generalised estimating equation model adjusted for pre-hospital confounders. Sensitivity analysis was also performed using a propensity score matching method.

Results: Among 1254 patients (day-time: 948, night-time: 306), the night-time patients had a significantly shorter IHCPR duration (27.8 min vs. 23.6 min, adjusted difference: -5.1 min, 95% confidence interval [CI]: -6.7, -3.4), a higher incidence of chest injuries (40.4% vs. 67.0%, adjusted odds ratio [AOR]: 1.27, 95% CI: 1.20, 1.35), and a lower rate of return of spontaneous circulation (38.4% vs. 26.5%, AOR: 0.93, 95% CI: 0.88, 0.98). No significant differences were observed in the rates of survival to emergency department and hospital discharge. The propensity score-matched analysis revealed similar results.

Conclusions: Patients who underwent night-time treatment for OHCA had an increased risk of CPR-related chest injuries despite their shorter resuscitation duration. Further studies are needed to clarify the underlying mechanism(s).