Abstract Body: Background:
The effect of temperature control after extracorporeal cardiopulmonary resuscitation (ECPR) remains unknown. This study aimed to compare the clinical outcomes and adverse events between hypothermic and normothermic temperature control in patients with out-of-hospital cardiac arrest (OHCA) treated with ECPR.

Methods:
We performed a secondary analysis of the SAVE-J II study, a retrospective multicenter study of OHCA patients ≥18 years treated with ECPR between 2013 and 2018. Adult patients with OHCA who received temperature control after ICU admission were included. The primary outcome was survival rate at hospital discharge. The secondary outcome was favorable neurological outcome at hospital discharge (cerebral performance category score 1 or 2) and adverse events (cannulation-related bleeding, hemorrhage, and ischemia). Patients were divided into two groups, hypothermia (target temperature: 32–34°C) and normothermia (target temperature: 36°C) groups.

Results:
Of 2,157 patients registered in the SAVE-J II study, 926 patients were ultimately included for analysis, 555 patients in the hypothermia group and 371 patients in the normothermia group. Survival rate in hypothermia and normothermia groups were 41.8% and 27.0%, respectively (p < 0.001). The proportion of favorable outcome in hypothermia and normothermia groups were 19.6% and 14.6%, respectively (p = 0.045). The incidence of cannulation-related bleeding, hemorrhage, and ischemia in hypothermia and normothermia groups were 17.0% and 19.2% (p = 0.389), 7.9% and 12.5% (p = 0.024), and 2.5% and 1.6% (p = 0.349), respectively. Hypothermia was significantly associated with in-hospital survival (odds ratio [OR], 1.67; 95% confidence interval [CI], 1.23–2.28; P = 0.001) and was not significantly associated with favorable neurological outcomes (OR, 1.16; 95% CI, 0.79–1.70; P = 0.454).

Conclusion:
Hypothermic temperature control in patients with OHCA receiving ECPR was associated with survival rate at hospital discharge. We are currently conducting a randomized controlled trial on temperature control in patients with OHCA receiving ECPR.