Arterial Oxygen and Carbon Dioxide Tension and Acute Brain Injury in Extracorporeal Cardiopulmonary Resuscitation Patients: Analysis of the Extracorporeal Life Support Organization Registry

Abstract

Objective: Acute brain injury remains common after extracorporeal cardiopulmonary resuscitation. Using a large international multicenter cohort, we investigated the impact of peri-cannulation arterial oxygen (PaO2) and carbon dioxide (PaCO2) on ABI occurrence. Design: Retrospective cohort study. Setting: Data in the Extracorporeal Life Support Organization Registry from 2009 to 2020. Patients: Adult patients (≥18 years old) who underwent extracorporeal cardiopulmonary resuscitation. Interventions: None. Measurements and Main Results: Of 3,125 patients with extracorporeal cardiopulmonary resuscitation (median age=58, 69% male), 488 (16%) experienced at least one form of acute brain injury, which included ischemic stroke, intracranial hemorrhage, seizures, and brain death. 217 (7%) experienced ischemic stroke and 88 (3%) experienced intracranial hemorrhage. The registry collects two blood gas data pre- (6 hours before) and on- (24 hours after) extracorporeal membrane oxygenation (ECMO) cannulation. Blood gas parameters were classified as: hypoxia (<60mmHg), normoxia (60-119mmHg), and mild (120-199mmHg), moderate (200-299mmHg), and severe hyperoxia (≥300mmHg); hypocarbia (<35mmHg), normocarbia (35-44mmHg), mild (45-54mmHg) and severe hypercarbia (≥55mmHg). In multivariable logistic regression analysis, pre-ECMO hypoxia (aOR=1.46, 95%CI: 1.03-2.08, p=0.04) and on-ECMO severe hyperoxia (aOR=1.55, 95%CI: 1.02-2.36, p=0.04) were associated with composite ABI. Also, on-ECMO severe hyperoxia was associated with intracranial hemorrhage (aOR=1.88, 95%CI: 1.02-3.47, p=0.04) and in-hospital mortality (aOR=3.51, 95%CI: 1.98-6.22, p<0.001). Pre- and on-ECMO PaCO2 levels were not significantly associated with composite ABI or mortality, though mild hypercarbia pre- and on-ECMO were protective of ischemic stroke and intracranial hemorrhage, respectively. Conclusions: Early severe hyperoxia (≥300mmHg) on ECMO was a significant risk factor for acute brain injury and mortality for patients undergoing extracorporeal cardiopulmonary resuscitation. Careful consideration should be given in early oxygen delivery in ECPR patients who are at risk of reperfusion injury.