BACKGROUND: Ventricular assist devices are widely used in patients with heart failure. Although different blood pumps havebeen developed and used throughout the world, few blood pumps are used in China because of the high prices. Development of aless expensive pump for clinical use is urgently needed in China.OBJECTIVE: To test the hemolytic characteristics of an implantable magnetic suspension centrifugal ventricular assist devicein vitro.METHODS: The flow field of the blood pump was analyzed with the computational fluid dynamics. Blood pumps were connected ina mock circulatory loop, filled with fresh sheep blood, and the pump generated 5 L/min flow against a head pressure of 100 mm Hg(1 mm Hg=0.133 kPa). The in vitro hemolytic properties were evaluated by determining the level of plasma free hemoglobin atdefined intervals.RESULTS AND CONCLUSION: Based on the computational fluid dynamics, a stable blood flow line was shown inside the pump,the wall shear stress inside the pump was less than 68.5 Pa and the internal static pressure distribution was smooth withoutadverse area. The normalized index of hemolysis was (0.075±0.017) mg/L. The blood pump showed satisfactory hemolyticproperties as compared with the other third generation pumps. No mechanical failure occurred during the experiments. Therefore,long-term in vivo circulation assist experiment of the new blood pump could be carried on to evaluate its hemodynamics andend-organ effect in the future.%背景:心室辅助装置已广泛应用于心力衰竭患者的治疗.虽然有不同的血泵在国外应用于临床,却很少在国内应用,主要原因是其价格太高.因此在国内研制相对价格较低的能应用于临床的自主血泵迫在眉睫.目的:测试置入式磁悬浮离心心室辅助装置主体血泵的溶血性能.方法:通过计算流体力学方法,对磁悬浮离心式心室辅助装置主体血泵内部流场做初步分析.血泵在后负荷100 mm Hg (1 mm Hg=0.133 kPa)、流量5 L/min 情况下,通过体外模拟血循环系统驱动羊血测试血泵体外溶血性能,计算血泵实际标准溶血指数NIH.结果与结论:在设计工况下计算流体力学结果显示血泵内部流线平稳,整个流道内部壁面剪切力均在68.5 Pa以下,内部静压力分布均匀,过渡平稳,没有不良区域出现.体外溶血实验测得标准溶血指数NIH值为(0.075±0.017) mg/L.提示血泵驱动叶片及内部流道设计合理,同第3代血泵相比有较好溶血性能.血泵实验期间无不良状况发生,可以进行下一步长期的动物体内实验,进而评估血泵体内血流动力学性能和血泵置入对实验动物脏器的影响.
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