Hyperoxia and mortality in conventional versus extracorporeal cardiopulmonary resuscitation

Hyperoxia has been associated with adverse outcomes in post cardiac arrest (CA) patients. Study-objective was to examine the association between hyperoxia and 30-day mortality in a mixed cohort of two different modes of Cardiopulmonary Resuscitation (CPR): Extracorporeal (ECPR) vs. Conventional (CCPR).In this retrospective cohort study of CA patients admitted to a tertiary level CA centre in Australia (over a 6.5-year time period) mean arterial oxygen levels (PaO2) and episodes of extreme hyperoxia (maximum of mean PaO2 ≥ 300 mmHg) were analysed over the first 8 days post CA.One hundred and sixty-nine post CA patients were assessed (ECPR n = 79 / CCPR n = 90). Mean PaO2-levels were higher in the ECPR vs CCPR group (211 mmHg ± 58.4 vs 119 mmHg ± 18.1; p < 0.0001) as was the proportion with at least one episode of extreme hyperoxia (74.7% vs 16.7%; p < 0.001). After adjusting for confounders and the mode of CPR any episode of extreme hyperoxia was independently associated with a 2.52-fold increased risk of 30-day mortality (OR: 2.52, 95% CI: 1.06-5.98; p = 0.036).We found extreme hyperoxia was more common in ECPR patients in the first 8 days post CA and independently associated with higher 30-day mortality, irrespective of the CPR-mode.