EVALUATION OF THE GAS TRANSFER RATE OF AN IMPROVED MODEL IN MENOX EL-4000 FOR IMPLANTABLE OXYGENATOR

Abstract

In a previous study, we evaluated the relationship between housing geometry and the velocity distribution of MENOX EL-4000 (DAINIPPON INK & CHEMICALS, INC) using CFD (Computational Fluid Dynamics). An improved model was designed for implant and set up in the same direction to attach the inlet port to the auricle of the left atrium and the outlet port to the pulmonary artery. The oxygenator has an oviduct shape in the XZ plane and a circular arc shape in the YZ plane. The velocity distribution was calculated based on Darcy's law (on the assumption that the hollow fibers behave as a porous media). In the results of CFD analysis, it was indicated that the velocity in the hollow fiber shows almost the same rate and the stagnation area decreased 82.74% drastically. In addition, we manufactured the improved model to evaluate the animal experiments. To improve the blood compatibility, the whole inner part was coated with DLC (Diamond Like Carbon). The results of the animal experiments, we could decrease the thrombus formation area than usual model and find the improvement of the higher gas transfer rate. The gas transfer performance increased 1.27 times in the case of O2 and 3.32 times in the case of CO2 than the original model when the blood flow rate was 3L/min. In conclusion, we confirmed that the gas transfer rate was increased by improved housing geometry. It was considered that the same velocity in the hollow fiber influenced gas transfer rate.