Early hyperoxia and 28-day mortality in patients on venoarterial ECMO support for refractory cardiogenic shock: a bicenter retrospective propensity score-weighted analysis

Abstract

Background The mortality rate for a patient with a refractory cardiogenic shock on venoarterial (VA) extracorporeal membrane oxygenation (ECMO) remains high, and hyperoxia might worsen this prognosis. The objective of the present study was to evaluate the association between hyperoxia and 28-day mortality in this setting. Methods We conducted a retrospective bicenter study in two French academic centers. The study population comprised adult patients admitted for refractory cardiogenic shock. The following arterial partial pressure of oxygen (PaO2) variables were recorded for 48 h following admission: the absolute peak PaO2 (the single highest value measured during the 48 h), the mean daily peak PaO2 (the mean of each day’s peak values), the overall mean PaO2 (the mean of all values over 48 h), and the severity of hyperoxia (mild: PaO2 < 200 mmHg, moderate: PaO2 = 200–299 mmHg, severe: PaO2 ≥ 300 mmHg). The main outcome was the 28-day all-cause mortality. Inverse probability weighting (IPW) derived from propensity scores was used to reduce imbalances in baseline characteristics. Results From January 2013 to January 2020, 430 patients were included and assessed. The 28-day mortality rate was 43%. The mean daily peak, absolute peak, and overall mean PaO2 values were significantly higher in non-survivors than in survivors. In a multivariate logistic regression analysis, the mean daily peak PaO2, absolute peak PaO2, and overall mean PaO2 were independent predictors of 28-day mortality (adjusted odds ratio [95% confidence interval per 10 mmHg increment: 2.65 [1.79–6.07], 2.36 [1.67–4.82], and 2.85 [1.12–7.37], respectively). After IPW, high level of oxygen remained significantly associated with 28-day mortality (OR = 1.41 [1.01–2.08]; P = 0.041). Conclusions High oxygen levels were associated with 28-day mortality in patients on VA-ECMO support for refractory cardiogenic shock. Our results confirm the need for large randomized controlled trials on this topic.

Determinants of Arterial Pressure of Oxygen and Carbon Dioxide in Patients Supported by Veno-Arterial ECMO

“…Even though we did not specifically measure it, our findings suggest that the retrograde aortic flow of VA ECMO was able to reach the proximal aortic arch (i.e., right radial artery). We did not find an association between hemoglobin and oxygenation, as described by some authors for VV ECMO [ 12 , 23 , 24 ]. This can be explained by the hemoglobin value, which was not very low in the patients from our cohort, and the Q EC which was high, thus maintaining oxygen delivery [ 23 ].…”

Hyperoxia in patients on venoarterial extracorporeal membrane oxygenation

“…To the editor, We read with great interest the article by Moussa et al which illustrated the association between early hyperoxia and 28-day mortality in patients on venoarterial extracorporeal membrane oxygenation (VA-ECMO) support for refractory cardiogenic shock [1]. Hyperoxia might increase oxidative stress, leading to worse outcomes [2].…”

Hyperoxia during venoarterial ECMO: Culprit or co-variate? A comment from the BLENDER investigators

“…Several observational studies have examined the association between hyperoxia during VA-ECMO and patient outcomes and the findings are inconsistent [6,[9][10][11][12]. The methodology of these studies have been highly variable and although the demonstrated effect of hyperoxia has varied a high prevalence of hyperoxia amongst VA-ECMO patients has been ubiquitous [7,[9][10][11][12].…”

“…Patients requiring Venoarterial extracorporeal membrane oxygenation (VA-ECMO), may be at increased risk from hyperoxia due to pre-existing oxidative stress from ischemia reperfusion injury and a high prevalence of extreme hyperoxia [ 6 , 7 ]. As such the control and effect of hyperoxia exposure during VA-ECMO requires investigation.…”