Abstract 154: Hyperoxemia is Associated with Poor Neurological Outcomes in Patients with Out-of-hospital Cardiac Arrest Rescued by Extracorporeal Cardiopulmonary Resuscitation: Insight From the Nationwide Multicenter Observational JAAM-OHCA (Japan Association for Acute Medicine) Registry

Abstract

Introduction: Previous studies have shown an association between hyperoxemia and mortality in out-of-hospital cardiac arrest (OHCA) patients after cardiopulmonary resuscitation (CPR); however, the evidence is lacking in patients receiving extracorporeal CPR (ECPR). Hypothesis: To test the hypothesis that hyperoxemia is associated with poor neurological outcome in patients treated by ECPR. Methods: The Japanese Association for Acute Medicine - OHCA (JAAM-OHCA) Registry is a multicenter, prospective, observational registry including 34,754 OHCA patients between 2014 and 2017. Patients who had been resuscitated and survived 24 hours after OHCA and had a PaO 2 levels above 60 mmHg were included. Eligible patients were divided into 2 groups by each 2 definition according to the PaO 2 levels measured from arterial blood gas analysis 24-h after the ECPR, (1) High-level of PaO 2 (H-PaO 2 , n=242) as PaO 2 ≥ 157 mmHg (median) and control (n=211) as 60 < PaO 2 < 157 mmHg, (2) hyperoxemia (HO, n=80) as PaO 2 ≥ 300 mmHg and control (n=373) as 60 < PaO 2 < 300 mmHg. The primary and secondary outcomes were the favorable neurological outcome, defined as Cerebral Performance Categories (CPC) Scale 1-2, and survival at 30 days after OHCA, respectively. Results: Out of 34,754 patients with OHCA, 453 patients with ECPR were included. The number of CPC 1-2 was significantly lower in the H-PaO 2 and HO group compared with each control group (H-PaO 2 : 17.4% vs. 33.2%; Odds ratio [OR] 0.42; 95% confidence interval [CI] 0.27-0.66; P<0.0001, HO: 8.8% vs. 28.2%; OR 0.24; 95% CI 0.11-0.55; P<0.001). The 30-day survival was lower in these high oxygen groups (H-PaO 2 : 39.3% vs. 57.4%; OR 0.48; 95% CI 0.33-0.70; P<0.0001, HO: 25.0% vs. 52.6%; OR 0.30; 95% CI 0.17-0.52; P<0.0001). After adjusting for potential confounders, the H-PaO 2 and HO were associated with unfavorable neurological outcomes (adjusted OR, H-PaO 2 ; 2.71; 95% CI 1.16-6.30; P=0.021, HO; 5.76; 95% CI 1.30-25.4; P=0.021). The H-PaO 2 and HO were also associated with poor 30-day survival (adjusted OR, H-PaO 2 ; 2.28; 95% CI 1.13-4.60; P=0.021, HO; 3.75; 95% CI 1.28-11.0; P=0.016). Conclusions: Hyperoxemia was associated with worse neurological outcomes in OHCA patients with ECPR.