基于肺动脉下心室旷置术腔-肺辅助装置的建模仿真及无传感器反馈控制算法研究

Study on modeling,simulation,and sensorless feedback control algorithm of the cavopulmonary assist device based on the subpulmonary ventricular exclusion

肺动脉下心室旷置术(Fontan)在临床上能够有效改善功能性单心室患儿的生存质量,然而术后容易发生Fontan循环衰竭,导致临床施行Fontan存在明显局限,腔-肺辅助装置(CPAD)是目前解决其局限性的有效手段。因此,本文通过搭建单心室患儿Fontan循环衰竭和CPAD的计算机仿真和体外实验耦合模型,评估CPAD对于Fontan循环衰竭的效果,并设计了一种无传感器反馈控制算法,用于提供足够心输出量和预防CPAD恒定血泵转速导致的腔静脉抽吸现象。该无传感器反馈控制算法基于CPAD血泵转速这一固有参数,通过扩展卡尔曼滤波器准确估算腔肺压力差(CPPH),摒除了压力传感器无法长期使用的缺点,并采用增益调度比例积分(PI)控制器,使实际CPPH值逼近参考值。结果表明,CPAD能够有效提高患儿的生理灌注并减少单心室负荷,并且无传感器反馈控制算法可以有效地保证心输出量并预防抽吸现象。本研究可为CPAD的设计和优化提供理论依据和技术支持,具有潜在的临床应用价值。

The subpulmonary ventricular exclusion(Fontan)could effectively improve the living quality for the children patients with a functional single ventricle in clinical.However,postoperative Fontan circulation failure can easily occur,causing obvious limitations while clinically implementing Fontan.The cavopulmonary assist devices(CPAD)is currently an effective means to solve such limitations.Therefore,in this paper the in-silico and in-vitro experiment coupled model of Fontan circulation failure for the children patients with a single ventricle and CPAD is established to evaluate the effects of CPAD on the Fontan circulation failure.Then a sensorless feedback control algorithm is proposed to provide sufficient cardiac output and prevent vena caval suction due to CPAD constant pump speed.Based on the CPAD pump speed-an intrinsic parameter,the sensorless feedback control algorithm could accurately estimate the cavopulmonary pressure head(CPPH)using extended Kalman filter,eliminating the disadvantage for pressure sensors that cannot be used in long term.And a gain-scheduled,proportional integral(PI)controller is used to make the actual CPPH approach to the reference value.Results show that the CPAD could effectively increase physiological perfusion for the children patients and reduce the workload of a single ventricle,and the sensorless feedback control algorithm can effectively guarantee cardiac output and prevent suction.This study can provide theoretical basis and technical support for the design and optimization of CPAD,and has potential clinical application value.