Identifying the optimal timing of renal replacement therapy initiation among critically ill patients on extracorporeal membrane oxygenation therapy

Introduction: Acute kidney injury (AKI) is one of the most frequent complications in patients with severe cardiopulmonary dysfunction on extracorporeal membrane oxygenation (ECMO) therapy. Although renal replacement therapy (RRT) is the standard of care for AKI, the timing of initiation of RRT remains controversial.Objectives: This study aimed to determine the optimal timing of RRT initiation among patients receiving ECMO therapy.Patients and Methods: We conducted a retrospective cohort study of 40 patients in a tertiary hospital centre from March 2014 until December 2019. The patients were divided into two groups according to the timing of RRT initiation, i.e. early RRT (within 72 hours) or late RRT after ECMO treatment. The primary outcome was 60-day mortality. The secondary outcomes were survival predictors of these patients.Results: The 60-day mortality was not significantly different between the two groups (76.9% in the early RRT initiation and 88.9% in the late group; P = 0.321). The predictors of survival were RRT start within 72 hours of ECMO initiation (HR: 0.067, 95%, CI: 0.010-0.457), age >_ 60 years (HR: 6.334, 95% CI: 1.268-31.625), fluid balance on day seven of ECMO (HR: 1.093, 95% CI: 1.007-1.187), and eGFR-EPI >_ 60 mL/min/1.73 m2 (HR: 0.970, 95% CI: 0.946-0.996). Conclusion: Among patients with ECMO and RRT, early RRT within 72 hours of ECMO initiation was significantly associated with a decreased risk of death. Our findings suggest the survival benefit of early RRT in critically ill patients treated with ECMO.