Impact of acute kidney injury in different ECMO modalities: a multicenter retrospective study on risk factors and mortality.

Acute kidney injury (AKI) is a common and serious complication in critically ill patients receiving extracorporeal membrane oxygenation (ECMO), significantly affecting mortality and long-term renal function. However, risk factors and clinical course of AKI across different ECMO modalities remain poorly understood. Herein, our study identified independent risk factors for AKI in ECMO patients and evaluated the effect of AKI severity on 30-day mortality. This multicenter retrospective cohort study enrolled patients from three ECMO centers (September 2019-June 2024). AKI was defined and staged according to KDIGO serum creatinine criteria within 7 days after ECMO initiation. Multivariate stepwise logistic regression identified predictors of moderate-to-severe AKI (stages 2-3). Cox proportional-hazards models assessed the association between AKI stage and 30-day mortality. Among 210 patients, 110 (52.4%) developed AKI stages 2-3 within 7 days. Serial monitoring showed a progressive increase in stage 2, while stage 3 plateaued. Moderate-to-severe AKI was independently associated with 30-day mortality. In the overall cohort, VA-ECMO modality and norepinephrine use were independent risk factors for AKI stages 2-3, while high fibrinogen (FIB) level and a history of cardiovascular disease (CVD) were protective. In the VV-ECMO subgroup, elevated lactate, bicarbonate, FIB, procalcitonin, and blood urea nitrogen levels, along with decreased total bilirubin and white blood cell counts were significantly associated with increased moderate-to-severe AKI risk. Herein, our study indicated that severe AKI independently predicts 30-day mortality in ECMO patients. VA-ECMO modality and NE use increase moderate-to-severe AKI risk, while high FIB level and CVD provide protection.