Asakawa Yuichi, Funakubo Akio, Fukunaga Kazuyoshi, Taga Ichiro, Higami Tetsuya, Kawamura Tsuyoshi, Fukui Yasuhiro
Department of Electronic and Computer Engineering, Tokyo Denki University, Japan.
ASAIO J. 2006 May-Jun;52(3):291-5. doi: 10.1097/01.mat.0000216165.21432.ee.
Thrombogenicity, a problem with long-term artificial lungs, is caused by blood-biomaterial interactions and is made worse by nonuniform flow, which also causes decreased gas exchange. To overcome these obstacles, we changed the inlet and added a uniform flow pump to our previous oxygenator design. Conventional membrane oxygenators have a (1/2)-inch port for the inlet of blood. These port structures make it difficult for the blood to flow uniformly in the oxygenator. In addition, the complex blood flow patterns that occur in the oxygenator, including turbulence and stagnation, lead to thrombogenicity. A cross-flow pump (CFP) can result in uniform blood flow to the inlet side of an oxygenator. In this study, we evaluated the usefulness of an integrated oxygenator with a fiber bundle porosity of 0.6 and a membrane surface area of 1.3 m2. The inlet part of the oxygenator is improved and better fits the outlet of the CFP. Each of the three models of the improved oxygenator has a different inlet taper angle. The computational fluid dynamics analysis showed that, compared with the original design, uniform flow of the integrated oxygenator improved by 88.8% at the hollow fiber membrane. With the integrated oxygenator, O2 transfer increased by an average of 20.8%, and CO2 transfer increased by an average of 35.5%. The results of our experiments suggest that the CFP, which produces a wide, uniform flow to the oxygenator, is effective in attaining high gas exchange performance.
血栓形成是长期使用人工肺面临的一个问题，它由血液与生物材料的相互作用引起，非均匀流动会使其恶化，而非均匀流动还会导致气体交换减少。为克服这些障碍，我们对入口进行了改进，并在之前的氧合器设计中增加了一个均匀流泵。传统的膜式氧合器有一个用于血液入口的半英寸端口。这些端口结构使血液难以在氧合器中均匀流动。此外，氧合器中出现的复杂血流模式，包括湍流和停滞，会导致血栓形成。横流泵（CFP）可以使血液均匀地流向氧合器的入口侧。在本研究中，我们评估了纤维束孔隙率为0.6且膜表面积为1.3平方米的一体化氧合器的实用性。氧合器的入口部分经过改进，能更好地适配横流泵的出口。改进后的氧合器的三种型号各有不同的入口锥角。计算流体动力学分析表明，与原始设计相比，一体化氧合器在中空纤维膜处的均匀流动提高了88.8%。使用一体化氧合器时，氧气传输平均增加了20.8%，二氧化碳传输平均增加了35.5%。我们的实验结果表明，能为氧合器产生广泛、均匀流动的横流泵在实现高气体交换性能方面是有效的。
