PDF(Pubmed)
Abstract：
Microfluidic devices promise to overcome the limitations of conventional hemodialysis and oxygenation technologies by incorporating novel membranes with ultra-high permeability into portable devices with low blood volume. However, the characteristically small dimensions of these devices contribute to both non-physiologic shear that could damage blood components and laminar flow that inhibits transport. While many studies have been performed to empirically and computationally study hemolysis in medical devices, such as valves and blood pumps, little is known about blood damage in microfluidic devices. In this study, four variants of a representative microfluidic membrane-based oxygenator and two controls (positive and negative) are introduced, and computational models are used to predict hemolysis. The simulations were performed in ANSYS Fluent for nine shear stress-based parameter sets for the power law hemolysis model. We found that three of the nine tested parameters overpredict (5 to 10×) hemolysis compared to empirical experiments. However, three parameter sets demonstrated higher predictive accuracy for hemolysis values in devices characterized by low shear conditions, while another three parameter sets exhibited better performance for devices operating under higher shear conditions. Empirical testing of the devices in a recirculating loop revealed levels of hemolysis significantly lower (<2 ppm) than the hemolysis ranges observed in conventional oxygenators (>10 ppm). Evaluating the model\'s ability to predict hemolysis across diverse shearing conditions, both through empirical experiments and computational validation, will provide valuable insights for future micro ECMO device development by directly relating geometric and shear stress with hemolysis levels. We propose that, with an informed selection of hemolysis parameters based on the shear ranges of the test device, computational modeling can complement empirical testing in the development of novel high-flow blood-contacting microfluidic devices, allowing for a more efficient iterative design process. Furthermore, the low device-induced hemolysis measured in our study at physiologically relevant flow rates is promising for the future development of microfluidic oxygenators and dialyzers.
摘要：
微流体装置有望通过将具有超高渗透性的新型膜结合到具有低血容量的便携式装置中来克服常规血液透析和氧合技术的限制。然而,这些装置的特征小尺寸导致可能损害血液成分的非生理剪切和抑制运输的层流。虽然已经进行了许多研究以经验和计算方式研究医疗设备中的溶血，比如瓣膜和血泵，对微流控装置中的血液损伤知之甚少。在这项研究中,介绍了代表性的基于微流体膜的充氧器的四个变体和两个对照（阳性和阴性），和计算模型用于预测溶血。在ANSYSFluent中对幂律溶血模型的9个基于剪切应力的参数集进行了模拟。我们发现，与经验实验相比，九个测试参数中有三个会过度预测（5至10倍）溶血。然而,三个参数集对低剪切条件下设备中溶血值的预测准确性更高，而另外三个参数组对于在较高剪切条件下操作的装置表现出更好的性能。在再循环回路中对装置的经验测试揭示溶血水平显著低于(<2ppm)在常规氧合器中观察到的溶血范围(>10ppm)。评估模型在不同剪切条件下预测溶血的能力，通过经验实验和计算验证，通过直接将几何和剪切应力与溶血水平相关联，将为未来的微型ECMO设备开发提供有价值的见解。我们建议,根据测试设备的剪切范围对溶血参数进行明智的选择，计算模型可以补充新型高流量血液接触微流体设备开发中的经验测试，允许更有效的迭代设计过程。此外，在我们的研究中，在生理相关的流速下测得的低设备诱导的溶血对于微流体充氧器和透析器的未来发展是有希望的。
