基于血流动力学效应优化的体外反搏闭环反馈调控研究

Research on the closed-loop feedback regulation of enhanced external counterpulsation based on hemodynamic effect optimization

目的 本文旨在实现针对不同的患者个体,以较优的血流动力学效应为目标,实现个性化的体外反搏(enhanced external counterpulsation,EECP)的闭环反馈调控数值模拟。方法 通过集中参数模型模拟研究EECP反搏模式对不同的适应症的影响机制,根据PID控制系统的反馈调节原理,将其应用于体外反搏的研究中,把血液循环系统的闭环式0维集中参数模型作为被控对象,用于个性化体外反搏血流动力学仿真。结合体外反搏局部血流动力学效应评价模型为不同适应症(冠心病或脑卒中)患者设定血流动力学效应优化的个性化目标值,根据设定目标值和当前血流动力学指标之间的误差,通过设置适当的增益系数与误差进行运算来调节不同反搏模式(压力幅值或加压时长)使当前血流动力学指标达到设定目标值。结果 反搏压力对于冠状动脉血流动力学指标的增加更加明显。加压时长对于脑动脉的血流动力学效应的影响最为显著。因此对于冠心病患者设定优化目标值舒张压/收缩压(D/S),通过反馈调节反搏压力使当前D/S达到设定D/S,最终使它们之间误差e的绝对值降低至0.06(均<5%),并得到此时的压力幅值。对于脑卒中患者设定目标值脑血流量(cerebral blood flow,CBF),调节系统输入加压时长减小误差,控制系统的输出当前CBF达到设定CBF,使误差e的绝对值降低至0.06(均<5%)并得到此时的加压时长。结论 数值模拟中血流动力学指标达到优化目标值时应施加的压力幅值和加压时长可为临床体外反搏优化治疗提供理论依据。

Objective To achieve a personalized numerical simulation of counterpulsation mode feedback regulation in enhanced external counterpulsation(EECP) for different patients with better hemodynamic effects.Methods The influence mechanism of EECP counterpulsation mode on different indications is studied through the simulation of lumped parameter model.According to the feedback regulation principle of PID control system,it is applied in the study of EECP.The closed-loop 0 dimensional centralized parameter model of blood circulation system is taken as the controlled object for personalized external counterpulsation hemodynamic simulation.In combination with the evaluation model of local hemodynamic effects of extracorporeal counterpulsation,optimized personalized target values are set for patients with different indications(coronary heart disease or stroke).According to the error between the set target value and the current hemodynamic indicator,different counterpulsation modes(pressure amplitude or pressure duration) can be adjusted by setting appropriate proportion,integral and differential gain coefficients and the error to make the current hemodynamic index reach the set target value.Results The increase of pressure amplitude on the coronary hemodynamic index is more obvious.Pressure duration has the most significant effect on the hemodynamic effect of cerebral artery.Therefore,the optimal target value of diastolic blood pressure/systolic blood pressure(D/S) is set for patients with coronary heart disease,and the current D/S reaches the set D/S through feedback adjustment of pressure amplitude,and the absolute value of error between them is finally reduced to 0.06(average <5%),and the counterpulsation pressure is got at this time.For stroke patients with a target value of cerebral blood flow(CBF),the input pressure duration of the system is adjusted to reduce the error,and the current CBF of the output of the control system to reach the set CBF,reducing the absolute value of the error to 0.06(average <5%) and the pressure duration is obtained at this time.Conclusions When the hemodynamic indicators in numerical simulation reach the optimization target value,the counterpulsation pressure and pressure duration can provide theoretical basis for the clinical in EECP optimization treatment.