Comparison of the approaches to combine Renal Replacement Therapy with Extracorporeal Membrane Oxygenation - a Scoping Review.

Introduction: Extracorporeal membrane oxygenation (ECMO) is increasingly used for cardiac and respiratory failure and is associated with high rates of acute kidney injury (AKI) and fluid overload requiring renal replacement therapy (RRT). ECMO and RRT can be run independently in parallel, or RRT hemofilter or device can be integrated into the ECMO circuit. Several parallel and integrated ECMO-RRT configurations have been described, but the optimal approach remains uncertain.This scoping review mapped the available literature comparing at least two ECMO-RRT configurations, summarized reported outcomes, and identified knowledge gaps. Methods: We searched PubMed, Cochrane Library, Web of Science, Embase, and ClinicalTrials.gov without restrictions, with the final search conducted on February 9, 2026. Eligible studies compared at least 2 ECMO-RRT configurations linked to reported outcomes. Data on study characteristics, configurations, outcomes, and anticoagulation were extracted and synthesized. Results: Of 6,806 records, 20 studies were included: 12 were clinical including 1 randomized controlled trial, 3 in vitro, 1 in silico, and 4 surveys. More than 8 ECMO-RRT connection schemes have been described by clinical studies since 2013. No consistent differences in efficiency or clinical outcomes were observed between the configurations compared. Integrated methods were associated with longer or comparable hemofilter lifespan. Surveys confirmed heterogeneous medical practices, and 2 safety concerns (unstoppable pressure alarms and air embolism) were reported. Conclusion: Evidence on ECMO-RRT configurations is limited and heterogeneous. Future systematic and rigorous comparison of all the configurations through preclinical and clinical studies is needed to harmonize medical practices and inform the development of guidelines.