Impact of fluid balance on outcome of adult patients treated with extracorporeal membrane oxygenation.

Purpose: To assess the relationship between early daily fluid balance (FB) and 90-day outcome in adult patients treated with extracorporeal membrane oxygenation (ECMO).

Design: Retrospective observational study.

Setting: Tertiary referral centre for ECMO.

Patients: 115 patients treated with ECMO for refractory heart failure and 57 patients treated with ECMO for refractory respiratory failure.

Methods: We analysed the association between early daily FB versus hospital and 90-day mortality using multivariable logistic regression model, Cox proportional-hazards model and propensity score.

Results: We obtained detailed demographic, clinical, and biochemical data, daily FB, and continuous renal replacement days. Fifty-seven per cent of patients had acute kidney injury (AKI) at ECMO initiation, and 60 % (n = 103) of patients received continuous renal replacement therapy (CRRT) during ECMO course, beginning at a median of 1 (0-3.5) days after ECMO initiation. Overall 90-day mortality was 24 %. Survivors exhibited lower daily FB from day 3 to day 5. After adjustments, Acute Physiology and Chronic Health Evaluation (APACHE) III, CRRT during the first 3 days, major bleeding event at day 1 and positive FB on day 3 were independent predictors of 90-day mortality. Positive FB at ECMO day 3 remained an independent predictor of hospital and 90-day mortality, regardless of the statistical model used or the inclusion of a propensity score to have positive FB.

Conclusions: Positive FB at ECMO day 3 is an independent predictor of 90-day mortality. Further interventional studies aimed at testing the value of strategy of tight control of FB during the early ECMO period are now warranted.