Associations of long-term hyperoxemia, survival, and neurological outcomes in extracorporeal cardiopulmonary resuscitation patients undergoing targeted temperature management: A retrospective observational analysis of the SAVE-J Ⅱ study

•Patients with ECPR face survival and neurological outcomes-related complications.•Long-term hyperoxemia is associated with worse survival and neurological outcomes.•Avoiding hyperoxemia in ECPR is critical.•Oxygen toxicity must be carefully considered. Extracorporeal cardiopulmonary resuscitation (ECPR) can improve survival rates and neurological outcomes of patients with out-of-hospital cardiac arrest (OHCA). High levels of partial pressure of arterial oxygen (PaO2) negatively affect survival and neurological outcomes in patients with OHCA. However, research on associations of hyperoxemia with survival and neurological outcomes after ECPR remains limited, especially considering targeted temperature management (TTM) administration to patients. Additionally, few reports have examined the impact of hyperoxemia beyond 24 h. In this study, we aimed to examine the effect of prolonged hyperoxemia on survival and neurological outcomes after ECPR for OHCA in patients undergoing TTM. We performed a secondary observational analysis of data from the SAVE-J Ⅱ study, a retrospective, multicenter registry study of ECPR of patients with OHCA. Data on arterial PaO2 after ECPR for intensive care unit days 2–4 were collected and averaged. Patients were divided into two groups: hyperoxic (PaO2 ≥ 300 mmHg) and non-hyperoxic (PaO2