人工心脏提高主动脉瓣性能和血管搏动性的反馈控制

Feedback control for the artificial heart to improve aortic valve performance and vascular pulsatility

中文关键词  人工心脏  旋转式血泵  主动脉瓣性能  血管搏动性  反馈控制

英文关键词  artificial heart  rotary blood pumps  aortic valve performance  vascular pulsatility  feedback control

中文摘要

      本文针对一种旋转式血泵的人工心脏在临床上应用于心衰患者时因恒定泵速导致主动脉瓣永久闭合的现 象, 以及血管搏动性明显降低的缺点, 设计了一种新颖的反馈控制方法, 用于提高主动脉瓣性能和血管搏动性. 该 方法设定主动脉与左心室压力差(ΔP)的高低参考值(ΔPH/ΔPL), 采用增益调度PI控制器, 使ΔP实际值逼近一个 参考值后立即向另一个参考值逼近. 仿真结果表明, 此方法可以有效地提高血管搏动性、保证心输出量, 并使得主 动脉瓣间歇性开启的同时不引起抽吸和返流现象. 本文设计的控制系统可为旋转式血泵的设计和优化提供理论依 据和技术支持.

英文摘要

      Rotary blood pumps (RBP) as one type of artificial hearts, are currently operated at a fixed pump speed (PS) for the heart failure (HF) patients in clinical. However, fixed-PS operating mode may make permanent closure for the aortic valve, and obviously diminish vascular pulsatility. To overcome the above limitations, this study presents a new feedback control system for RBPs to meet the objective of aortic valve opening, while simultaneously increasing vascular pulsatility. Based on the difference between the aortic pressure and the left ventricular pressure (ΔP), the proposed algorithm sets the high and low reference values (ΔPH/ΔPL). A gain-scheduled, proportional integral (PI) controller maintains the actually measured ΔP at a high ΔP setpoint (ΔPH), leading to high RBP flow. When the value of ΔP approaches to ΔPH, the controller automatically switches to a lowΔP setpoint (ΔPL) that reduces RBP flow and generates pulsatility. The in-silico results using a combined human circulatory system and RBP model show that the proposed control algorithm effectively increased vascular pulsatility and maintained adequate physiologic perfusion, while intermittently opening the aortic valve to make sure that ventricular suction and backflow did not occur for all test conditions. The proposed control system could provide theoretical basis and technology support for designing and optimizing the RBPs.