Usefulness of Self-Expanding Drainage Cannula in Venovenous Extracorporeal Membrane Oxygenation: Tips, Tricks, and Results of an Early Experience

Inadequate venous drainage decreases the efficiency of extracorporeal membrane oxygenation (ECMO). Pump augmentation may even make it worse due to collapse of the venous system under negative pressures. Furthermore, recirculation is a phenomenon that occurs when oxygenated blood supplied through the infusion cannula is withdrawn directly through the drainage cannula without contributing to the oxygenation of the patient and also compromises the efficacy of the therapy. Large drainage cannulas allow for similar flow rates at lower pump speed. But percutaneous insertion of these larger cannulas could be challenging. When using a self-expandable cannula, the diameter of the cannula for the insertion can be reduced, and once inserted, its intravascular diameter maximized, resulting in a large venous cannula due to in situ expansion after mandrel removal (up to 36F). We present a retrospective series of selfexpanding venous cannula 430 or 530 mm in length in six consecutive patients undergoing venovenous (VV) ECMO. No vascular or cardiac iatrogenic injury was caused during implantation. Target flows were reached, and no clinically significant recirculation was described in any case. The use of selfexpanding drainage cannulas was safe, and efficient drainage was achieved with easy and definitive unique positioning during cannulation.