Numerical and Experimental Flow Analysis of the Wang-Zwische Double-Lumen Cannula

Abstract

An experimental and numerical analysis was performed for the Wang-Zwische double-lumen cannula (DLC) (Avalon Elite). The aim of this work was to provide insight for future improvement by characterizing the fluid dynamic behavior of the novel catheter with metrics often associated with blood trauma. Pressure and flow distributions were measured on a steady-flow rig using a 50% glycerol-water mixture by imposing a 2 L/min flow rate across the drainage and infusion lumens. The fluid was modeled as Newtonian with density of 1050 kg/m³ and dynamic viscosity of 0.0035 kg/m·s. Reynolds numbers typical for transitional flow (Re = 2000-2500) were computed within the lumens because of the changing cross-sections of the cannula geometry. Numerical computations were performed using the steady three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations and the low-Reynolds k-ω turbulence model. Discretization of governing equations was based on a cell-centered finite volume method. Numerical results correlated well with global performance of the cannula, allowing evaluation of the geometry toward potential blood trauma. Peak wall shear stress (WSS) in the drainage lumen was higher than that of infusion lumen, mainly due to the presence of side holes. Furthermore, recirculation regions were predicted in transition tubing to connectors of both the drainage and the infusion lumens because of adverse pressure gradients caused by the sudden enlargement of the cannula geometry. In this three-dimensional computational fluid dynamics (CFD) study, we observed higher peak WSS values for the drainage lumen, which may potentially cause blood trauma. Furthermore, recirculation regions were predicted in the proximity of the exit sections of both the infusion and drainage lumens, which may contribute to thrombosis formation. This study provides insight for future DLC modifications in minimizing cannula-induced blood trauma and thrombogenicity in long-term applications.

ECMO cannula review

“…Experimental and numerical studies of a double-lumen cannula showed that the shear stress was higher in the drainage lumen and regions of turbulence were found at the connection sites to tubing. 5 Additional features (insertion/sidearms). Cannulae inserted into peripheral arteries may nearly occlude the vessel volume and cause downstream ischaemia.…”

“…A commonly used approach is to use time-averaged equations (Reynolds-averaged Navier-Stokes equations -RANS) where the velocity is split into a mean and a variable component to allow for efficient numerical solutions. 5 CFD simulations of cannula flow are complex and often only possible using commercial simulation packages, so several authors have developed a simpler expression to estimate the flow-pressure relationship for cannulae. The formalism describes the performance of a cannula with a single number.…”

Fiber Bundle Design for an Integrated Wearable Artificial Lung

“…14,19,20,21,32,33 The ambulatory pump lung (APL) device features a fully magnetically levitated centrifugal pump integrated into a 0.8m 2 surface area annular fiber bundle 19 having 200 ml/min/m 2 oxygenation efficiency. The compliant thoracic artificial lung (cTAL) features a pumpless device with a 2.4m 2 surface area bundle having ~95 ml/min/m 2 oxygenation efficiency.…”

The Horizon is Always Ahead

“…6 New cannula design with dual lumen and bicaval insertion technique allows for femoralfree single site cannulation with enhanced patient mobility and improved gas exchange efficiency. 7 There has also been advancement in our understanding of patient management on VV-ECMO, including importance of minimal sedation, negative pressure spontaneous breathing, participation in physical therapy, and ambulation. We also have learned that bleeding remains the most frequent ECLS-related complication, and that reduction or even elimination of systemic anticoagulation may be appropriate in certain clinical settings.…”