Improvements in Vasopressor Requirements with Veno-Venous ECMO

Abstract

BackgroundVeno-venous extracorporeal membrane oxygenation (V-V ECMO) is increasingly used for severe respiratory failure. Some ECMO clinicians may view concurrent vasopressors as a contraindication for V-V ECMO. However, we noted improved vasopressor requirements after V-V ECMO cannulation. Research QuestionHow does V-V ECMO affect vasopressor requirements in patients with respiratory failure? MethodsRetrospective review of all V-V ECMO initiations from 12/2016-12/31/2023 at a large volume ECMO center. The change in norepinephrine equivalent dose and number of continuous intravenous vasopressors were determined immediately prior to, and 24 hours post V-V ECMO cannulation. This change was assessed by Wilcoxon signed-rank tests and their associations with potential predictor variables (pH, PaCO2, PaO2, PEEP) were examined by linear regressions. Results205 patients received V-V ECMO during this time, with 108 on vasopressors at ECMO cannulation and included in this analysis. The mean norepinephrine equivalent dose at ECMO initiation (0.23±0.29 mcg/kg/min) to 24 hours post ECMO (0.14±0.23 mcg/kg/min) significantly (p<0.001) decreased. The number of pressors at ECMO initiation (1.69±0.92) to 24 hours later (1.29±1.04) significantly (p<0.001) decreased. There was a significant decrease in PEEP, mean airway pressure, and PaCO2 with a significant increase in pH and PaO2 (all p ≤0.001). The changes in pH (p<0.001) were associated with changes in norepinephrine equivalent dose and number of vasopressors after adjusting for baseline outcomes. Twenty-seven (25%) patients had a norepinephrine equivalent dose ≥0.3 mcg/kg/min at ECMO initiation, of these 16 (59.3%) survived to hospital discharge (compared to 51.9% survival amongst those who had norepinephrine equivalent lower dose at ECMO initiation, p=0.66). InterpretationPatients’ vasopressor requirements significantly decreased 24 hours post V-V ECMO initiation, with a change in pH weakly associated with vasopressor improvement. Requirement of vasopressors, even norepinephrine equivalent dose of ≥0.3 mcg/kg/min at time of ECMO consideration, is not a clear contraindication to ECMO candidacy.