Hemodynamic and recirculation performance of dual lumen cannulas for venovenous extracorporeal membrane oxygenation

Abstract

Venovenous extracorporeal membrane oxygenation (ECMO) can be performed with two single lumen cannulas (SLCs) or one dual-lumen cannula (DLC) where low recirculation fraction ({R}_{f}) is a key performance criterion. DLCs are widely believed to have lower {R}_{f}, though these have not been directly compared. Similarly, correct positioning is considered critical although its impact is unclear. We aimed to compare two common bi-caval DLC designs and quantify {mathrm{R}}_{mathrm{f}} in several positions. Two different commercially available DLCs were sectioned, measured, reconstructed, scaled to 27Fr and simulated in our previously published patient-averaged computational model of the right atrium (RA) and venae cavae at 2–6 L/min. One DLC was then used to simulate ± 30° and ± 60° rotation and ± 4 cm insertion depth. Both designs had low {R}_{f} (< 7%) and similar SVC/IVC drainage fractions and pressure drops. Both cannula reinfusion ports created a high-velocity jet and high shear stresses in the cannula (> 413 Pa) and RA (> 52 Pa) even at low flow rates. Caval pressures were abnormally high (16.2–23.9 mmHg) at low flow rates. Rotation did not significantly impact {R}_{f}. Short insertion depth increased {R}_{f} (> 31%) for all flow rates whilst long insertion only increased {R}_{f} at 6 L/min (24%). Our results show that DLCs have lower {R}_{f} compared to SLCs at moderate-high flow rates (> 4 L/min), but high shear stresses. Obstruction from DLCs increases caval pressures at low flow rates, a potential reason for increased intracranial hemorrhages. Cannula rotation does not impact {R}_{f} though correct insertion depth is critical.