心衰脉动过程两级轴流血泵溶血数值模拟

Numerical simulation on hemolysis induced by two-stage axial-flow blood pump during pulsating heart failure

为了理解血泵脉动运行时流动对血液造成的损伤,建立了血泵和心血管循环系统多尺度模型.多尺度模型将零维尺度的心血管循环集中参数模型和三维尺度的轴流血泵内部流动分布式参数模型相结合.以两级轴流血泵为例,用Matlab仿真得到一个心动周期中两级轴流血泵的动态进出口压差和流量变化.其次,根据血泵内血流动力特性,将动态工况分段划分,并以这些流量作为准静态工况进行溶血程度计算.最后,将一个心动周期中准静态工况的溶血程度做时间加权平均,得到平均溶血程度值.结果表明,在一个心动周期中,由于血泵本身惯性的影响,使瞬态进出口压差-流量特性曲线呈一闭合的环状.同时,溶血程度大小在一个心动周期的变化规律和流量变化趋势相反,和进出口压差变化趋势相同.综上所述,多尺度模型的计算方法可以预估血泵在心衰脉动运行时的平均溶血程度.

To understand hemolysis of a blood pump under a pulsatile flow condition,a multi-scale model of the blood pump and cardiovascular circulatory system was built.This multi-scale model consists of a lumped parameter sub-model for the cardiovascular circulation and a three-dimensional distributed parameter sub-model for an axial-flow blood pump.Based on a specific two-stage axial-flow blood pump,the transient outlet pressure and flow rate through the pump were obtained by using the lumped model with Matlab simulation during a cardiac cycle under heart failure conditions.Then,according to the internal hemodynamic characteristics of the blood pump,the transient working condition was divided into a few flow rates,the hemolysis of the pump was predicted based on these flow rates in a quasi-steady manner.Finally,a time-weighted average hemolysis was calculated in one cardiaccycle.The results show that the pump transient pressure difference-flow rate curve is a closed loop in one cardiac cycle due to the inertia of the blood pump.Besides,the hemolysis and pressure difference exhibit a similar variation trend in one cardiac cycle,the flow rate is in an opposite variation trend.In summary,the method of multi-scale model can be used to estimate the hemolysis of a blood pump supporting patient with heart failure.