Exposure to Arterial Hyperoxia During Extracorporeal Membrane Oxygenator Support and Mortality in Patients with Cardiogenic Shock

Circulation: Heart Failure, Ahead of Print.
Background:Exposure to hyperoxia, a high arterial partial pressure of oxygen (PaO2), may be associated with worse outcomes in patients receiving extracorporeal membrane oxygenator (ECMO) support. We examined hyperoxia in the Extracorporeal Life Support Organization (ELSO) Registry among patients receiving venoarterial (VA) ECMO for cardiogenic shock (CS).Methods:We included ELSO Registry patients from 2010 to 2020 who received VA ECMO for CS, excluding extracorporeal CPR. Patients were grouped based on PaO2 after 24 hours of ECMO: normoxia (PaO2 60-150 mmHg), mild hyperoxia (PaO2 151-300 mmHg), and severe hyperoxia (PaO2 >300 mmHg). In-hospital mortality was evaluated using multivariable logistic regression.Results:Among 9959 patients, 3005 (30.2%) patients had mild hyperoxia and 1972 (19.8%) had severe hyperoxia. In-hospital mortality increased across groups: normoxia, 47.8%; mild hyperoxia, 55.6% (adjusted OR 1.37, 95% CI 1.23-1.53, p <0.001); severe hyperoxia, 65.4% (adjusted OR 2.20, 95% CI 1.92-2.52, p <0.001). A higher PaO2 was incrementally associated with increased in-hospital mortality (adjusted OR 1.14 per 50 mmHg higher, 95% CI 1.12-1.16, p <0.001). Patients with a higher PaO2 had increased in-hospital mortality in each subgroup and when stratified by ventilator settings, airway pressures, acid-base status, and other clinical variables. Higher PaO2 was the second strongest predictor of in-hospital mortality, after older age.Conclusions:Exposure to hyperoxia during VA ECMO support for CS is strongly associated with increased in-hospital mortality, independent from hemodynamic and ventilatory status. Until clinical trial data are available, we suggest targeting a normal PaO2 and avoiding hyperoxia in CS patients receiving VA ECMO.



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