Takiura K, Masuzawa T, Endo S, Wakisaka Y, Tatsumi E, Taenaka Y, Takano H, Yamane T, Nishida M, Asztalos B, Konishi Y, Miyazoe Y, Ito K
National Cardiovascular Center, Suita, Osaka, Japan.
Artif Organs. 1998 May;22(5):393-8. doi: 10.1046/j.1525-1594.1998.06149.x.
There are few established engineering guidelines aimed at reducing hemolysis for the design of centrifugal blood pumps. In this study, a fluid dynamic approach was applied to investigate hemolysis in centrifugal pumps. Three different strategies were integrated to examine the relationship between hemolysis and flow patterns. Hemolytic performances were evaluated in in vitro tests and compared with the flow patterns analyzed by flow visualization and computational fluid dynamic (CFD). Then our group tried to establish engineering guidelines to reduce hemolysis in the development of centrifugal blood pumps. The commercially available Nikkiso centrifugal blood pump (HPM-15) was used as a standard, and the dimensions of 2 types of gaps between the impeller and the casing, the axial and the radial gap, were varied. Four impellers with different vane outlet angles were also prepared and tested. Representative results of the hemolysis tests were as follows: The axial gaps of 0.5, 1.0, and 1.5 mm resulted in normalized index of hemolysis (NIH) values of 0.0028, 0.0013 and 0.0008 g/100 L, respectively. The radial gaps of 0.5 and 1.5 mm resulted in NIH values of 0.0012 and 0.0008 g/100 L, respectively. The backward type vane and the standard one resulted in NIH values of 0.0013 and 0.0002 g/100 L, respectively. These results revealed that small gaps led to more hemolysis and that the backward type vane caused more hemolysis. Therefore, the design parameters of centrifugal blood pumps could affect their hemolytic performances. In flow visualization tests, vortices around the impeller outer tip and tongue region were observed, and their patterns varied with the dimensions of the gaps. CFD analysis also predicted high shear stress consistent with the results of the hemolysis tests. Further investigation of the regional flow patterns is needed to discuss the cause of the hemolysis in centrifugal blood pumps.
针对离心式血泵的设计，几乎没有既定的旨在减少溶血的工程指导原则。在本研究中，采用流体动力学方法来研究离心泵中的溶血情况。整合了三种不同策略以检验溶血与流动模式之间的关系。在体外试验中评估溶血性能，并与通过流动可视化和计算流体动力学（CFD）分析的流动模式进行比较。然后我们团队试图在离心式血泵的研发过程中建立减少溶血的工程指导原则。使用市售的日机装离心式血泵（HPM - 15）作为标准，并改变叶轮与泵壳之间两种间隙类型（轴向间隙和径向间隙）的尺寸。还制备并测试了四个具有不同叶片出口角度的叶轮。溶血试验的代表性结果如下：轴向间隙为0.5、1.0和1.5毫米时，溶血归一化指数（NIH）值分别为0.0028、0.0013和0.0008克/100升。径向间隙为0.5和1.5毫米时，NIH值分别为0.0012和0.0008克/100升。后向型叶片和标准叶片的NIH值分别为0.0013和0.0002克/100升。这些结果表明，小间隙会导致更多的溶血，并且后向型叶片会引起更多的溶血。因此，离心式血泵的设计参数会影响其溶血性能。在流动可视化试验中，观察到叶轮外尖端和舌部区域周围的涡流，并且它们的模式随间隙尺寸而变化。CFD分析也预测到了与溶血试验结果一致的高剪切应力。需要对区域流动模式进行进一步研究，以探讨离心式血泵中溶血的原因。
