Impact of Cannulation Strategy and Extracorporeal Blood Flow on Recirculation During Veno‐Venous Extracorporeal Membrane Oxygenation

ABSTRACTIntroductionVeno‐venous extracorporeal membrane oxygenation (V‐V ECMO) is increasingly used in the treatment of severe respiratory failure. Despite a significant increase in the worldwide use of extracorporeal lung assist devices recirculation remains a common complication and is associated with a reduced effectiveness of ECMO support and increased hemolysis. In this observational study we aimed to investigate the impact of cannula configuration and extracorporeal flow on recirculation.Materials and MethodsAn observational retrospective study was performed, which included all patients, who received V‐V ECMO and recirculation measurements at the University Medical Center Freiburg between August 2021 and June 2023. Recirculation and extracorporeal flow were determined using ultrasonic indicator dilution technology. Patients were divided into subgroups according to their type of cannulation (dual lumen single‐site vs. bifemoral vs. femoro‐jugular).ResultsA total of 215 recirculation measurements in 47 patients were performed. Dual lumen single‐site cannulation was associated with significantly lower recirculation rates (8.7% [0.0; 12.0]) compared to single lumen dual‐site cannulation (femoro‐jugular: 17.6% [0.0; 25.8]; bifemoral: 27.9% ± 13.4%). In addition, a positive linear correlation was observed between extracorporeal flow and recirculation in all subgroups. Recirculation increased significantly with rising extracorporeal flow in all subgroups.ConclusionRecirculation is a common complication in V‐V ECMO and can lead to a reduction of ECMO effectiveness. Particular attention should be paid to optimal positioning of the cannulas in patients with more than one cannula. The ultrasonic indicator dilution method is a simple and quick method for measuring recirculation in V‐V ECMO and can be used at an early stage if effectiveness decreases.