Association of Volume Status During Veno-Venous Extracorporeal Membrane Oxygenation with Outcome

Fluid overload in acute respiratory distress syndrome is associated with increased mortality. The purpose of this study was to investigate the association of cumulative fluid balance (CFB) during the first 7 days of veno-venous extracorporeal membrane oxygenation (VV ECMO) and mortality. Adult patients on VV ECMO for greater than 168 hours, between November 2015 and October 2019, were included. CFB during the first 7 ECMO days was compared between survivors and nonsurvivors, and survival was analyzed using Kaplan-Meier analysis and cox proportional hazards modeling. One hundred forty-six patients were included. Median age was 45 years [32, 55], respiratory ECMO survival prediction score was 3 [0, 5], and P/F ratio was 70 [55, 85]. CFB for ECMO days 1-3 was +2,350 cc [-540, 5,941], days 4-7 -3,070 cc [-6,545, 437], and days 1-7 -341 cc [-4,579, 5,290]. One hundred seventeen patients (80%) survived to hospital discharge. Survivors were younger (41 years [31, 53] vs. 53 years [45, 60], p < 0.001) and had a higher respiratory ECMO survival prediction score, (3 [1, 5] vs. 1.5 [-1, 3], p = 0.002). VV ECMO survivors had a significantly more negative CFB during the first 7 days of VV ECMO (-1,311 cc [-4,755, 4,217] vs. 3,617 cc [-2,764, 9,413], p = 0.02), and CFB was an independent predictor of 90 day mortality (HR = 1.07 [1.01, 1.14], p = 0.02). Further studies are needed to determine the causal relationship between fluid balance and survival during VV ECMO.