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Abstracts: ASAIO Bioengineering/tissue Engineering Abstracts

COMPUTATIONAL MODELLING IN HOLLOW FIBRE GAS TRANSFER DEVICES (HFGTD): INFLUENCE OF FIBRES DISTRIBUTION ON O2 TRANSFER CAPACITY

Mallabiabarrena, I; Mucciolo, G; von Segesser, L K

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We report on our efforts using computational fluid dynamic (CFD) tools to compute the O2 transfer capacity of HFGTD. We propose a 3D model to describe O2 transfer in a reduced number of HFs regularly or randomly distributed. During last years, we have developed an intravenous HFGTD as a potential device for the treatment of acute respiratory problems. Comparing with extracorporeal HFGTD where HFs are regularly disposed, we describe our prototype as a randomly distributed bundle of HFs. We measured using in-vitro tests, the gas transfer capacity of our prototypes (VO2=47.2±3, VCO2=69.7±6 ml/min). Tests were run with different blood and gas flow rates (Qb=1–4 l/min, Qg=3–6 l/min). We assess from our data, that VO2 value in our devices is still limited. We presume the channelling effect due to random distribution of HF might decrease their O2 transfer capacity. A computational model is used to study the role of HF distribution on O2 transfer capacity. Fluid equations governing blood motion and advection-diffusion equation for O2 transport are solved using a CFD code (Fluent). Appropriate boundary conditions (BC) for blood motion and O2 transfer are computed. Inlet velocity is set for different Qb, O2 transfer BC through HF wall and surrounding fluid is fixed using experimentally computed mass transfer coefficients (3.1l<6.8*10-5 m/s). The CFD results indicate that channelling through randomly packed bundles can reduce O2 transfer capacity relative to regularly packed hollow fibre bundles. CFD offers a detailed understanding of blood motion and O2 transfer in HFGTD.

Copyright © 2005 by the American Society for Artificial Internal Organs