Duration of Hyperoxia and Neurologic Outcomes in Patients Undergoing Extracorporeal Membrane Oxygenation

Abstract

OBJECTIVES: To evaluate the impact of duration of hyperoxia on neurologic outcome and mortality in patients undergoing venoarterial extracorporeal membrane oxygenation. DESIGN: A retrospective analysis of venoarterial extracorporeal membrane oxygenation patients admitted to the Johns Hopkins Hospital. The primary outcome was neurologic function at discharge defined by modified Rankin Scale, with a score of 0–3 defined as a good neurologic outcome, and a score of 4–6 defined as a poor neurologic outcome. Multivariable logistic regression analysis was performed to evaluate the association between hyperoxia and neurologic outcomes. SETTING: The Johns Hopkins Hospital Cardiovascular ICU and Cardiac Critical Care Unit. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We measured first and maximum Pao 2 values, area under the curve per minute over the first 24 hours, and duration of mild, moderate, and severe hyperoxia. Of 132 patients on venoarterial extracorporeal membrane oxygenation, 127 (96.5%) were exposed to mild hyperoxia in the first 24 hours. Poor neurologic outcomes were observed in 105 patients (79.6%) (102 with vs 3 without hyperoxia; p = 0.14). Patients with poor neurologic outcomes had longer exposure to mild (19.1 vs 15.2 hr; p = 0.01), moderate (14.6 vs 9.2 hr; p = 0.003), and severe hyperoxia (9.1 vs 4.0 hr; p = 0.003). In a multivariable analysis, patients with worse neurologic outcome experienced longer durations of mild (adjusted odds ratio, 1.10; 95% CI, 1.01–1.19; p = 0.02), moderate (adjusted odds ratio, 1.12; 95% CI, 1.04–1.22; p = 0.002), and severe (adjusted odds ratio, 1.19; 95% CI, 1.06–1.35; p = 0.003) hyperoxia. Additionally, duration of severe hyperoxia was independently associated with inhospital mortality (adjusted odds ratio, 1.18; 95% CI, 1.08–1.29; p < 0.001). CONCLUSIONS: In patients undergoing venoarterial extracorporeal membrane oxygenation, duration and severity of early hyperoxia were independently associated with poor neurologic outcomes at discharge and mortality.

The Association of Oxygenation, Carbon Dioxide Removal, and Mechanical Ventilation Practices on Survival During Venoarterial Extracorporeal Membrane Oxygenation

“…Our study suggests that severe degrees of hyperoxemia (PaO 2 >200 mmHg) during the early stages of VA ECMO support is also very common. This is consistent with prior studies in ECMO patients ( 4 , 5 , 16 , 17 ). VA ECMO patients are critically unwell and reluctance among physicians in making too many early changes may also contribute to severe hyperoxemia during the early stages of VA ECMO support.…”

“…Our study finding is in contrast with multiple studies suggesting hyperoxemia is associated with increased mortality in VA ECMO supported patients. Al-Kawaz et al ( 17 ) in a single center study reported that duration and severity of early hyperoxemia were independently associated with poor neurologic outcomes at discharge as well as with mortality. However, Munshi et al ( 5 ) reported potential harm associated with hyperoxemia in venovenous ECMO patients and in those receiving VA ECMO in the context of cardiopulmonary resuscitation.…”

“…ROS have been postulated to be of major significance in tissue damage, organ dysfunction, and increased patient morbidity and mortality (9,(12)(13)(14). The harmful effects of hyperoxemia on ECMO may be dependent on the underlying condition, duration, and degree of the hyperoxemic exposure (5,13,(15)(16)(17). A lack of universal definition for hyperoxemia, lack of high-quality evidence, and lack of oxygen weaning guidelines have resulted in patients being exposed to prolonged periods of hyperoxemia on ECMO.…”

Narrative Review of Neurologic Complications in Adults on ECMO: Prevalence, Risks, Outcomes, and Prevention Strategies

“…When patients with poor cardiac function received VA ECMO, the brain is oxygenated by extracirculatory gas exchange. For patients on both VA and VV ECMO, early hyperoxia (within 24 h after ECMO onset) is significantly associated with higher mortality (84,85). Furthermore, early hyperoxia increases the risk of acute brain injury and unfavorable neurologic outcomes (84).…”

“…For patients on both VA and VV ECMO, early hyperoxia (within 24 h after ECMO onset) is significantly associated with higher mortality (84,85). Furthermore, early hyperoxia increases the risk of acute brain injury and unfavorable neurologic outcomes (84). However, the most appropriate strategy and correction target for PaO 2 and PaCO 2 in patients undergoing ECMO remain uncertain and need to be further studied.…”