An Optimized Multi-Stage Drainage Cannula Design for Venoarterial Extracorporeal Membrane Oxygenation

Venoarterial extracorporeal membrane oxygenation (VA ECMO) is a life-saving therapy that provides cardiorespiratory support for cardiogenic shock patients. But, due to altered flow dynamics induced by VA ECMO drainage cannulas, complications such as thrombosis and hemolysis are common. Therefore, this study aimed to develop an optimized drainage cannula design with reduced complication risk using computational fluid dynamics (CFD).

The multi-objective optimization process entailed generating a response surface based on a design of experiments with n = 540 unique cannula designs. Minimizing pressure drop, maintaining > 100 mm/s tip velocity, and minimization of average wall shear stress were assigned as objective functions. The optimized design was then tested in three patient-specific geometries using CFD and compared against a clinically available model (Maquet).

The final design consisted of three rows of five side holes, with all side holes titled at an angle of 31.5°. When compared to the Maquet model, the optimized cannula generated lower stagnant blood volumes, increased cannula tip velocities (> 300 mm/s), and increased drainage from the upper body.

The optimized cannula developed in this study demonstrated favorable flow dynamics that may increase flow and reduce the risk of life-threatening complications including thrombosis and hemolysis when translated to a clinical setting, thereby improving VA ECMO patient outcomes.