Impact of staff turnover on extracorporeal cardiopulmonary resuscitation in out-of-hospital cardiac arrest patients: a nationwide registry-based analysis in Japan.

Aim: To evaluate the impact of physician staff turnover on outcomes of out-of-hospital cardiac arrest (OHCA) patients, with a particular focus on those treated with extracorporeal cardiopulmonary resuscitation (ECPR). Methods: We conducted a nationwide retrospective cohort study using data from the Japanese Association for Acute Medicine OHCA Registry (2014-2022). Adult patients with cardiac arrest upon hospital arrival, including those who received ECPR, were analyzed. Patients were categorized by admission period: late March (18-31 March) and early April (1-14 April), corresponding to the annual physician turnover period in Japan. The primary outcome was 30-day survival. Multivariable logistic regression analysis was performed for both the overall OHCA cohort and the ECPR-treated cohort, adjusting for age, bystander CPR, initial rhythm at hospital arrival, and time from emergency call to hospital arrival. Results: The final cohort comprised 6036 OHCA patients, of whom 187 received ECPR. In the overall OHCA cohort, no significant difference in 30-day survival was observed between early April and late March. However, among ECPR patients, the 30-day survival rate was significantly higher in early April (36.1 %) than in late March (21.2 %) (p = 0.035), with an adjusted odds ratio of 2.28 (95 % confidence interval: 1.03-5.16; p = 0.044). Conclusions: While the physician turnover period had no discernible impact on outcomes in the overall OHCA population, it was significantly associated with improved survival among ECPR-treated patients. These findings suggest that ECPR may benefit from institutional preparedness during staff transition, but should be interpreted cautiously given the study limitations.