Tan Zhehuan, Huo Mingming, Qin Kairong, El-Baz Ayman S, Sethu Palaniappan, Wang Yu, Giridharan Guruprasad A
School of Biomedical Engineering, Dalian University of Technology, Dalian, China.
School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian, China.
Biomed Signal Process Control. 2023 May;83. doi: 10.1016/j.bspc.2023.104640. Epub 2023 Feb 16.
Continuous flow rotary blood pumps (RBP) operating clinically at constant rotational speeds cannot match cardiac demand during varying physical activities, are susceptible to suction, diminish vascular pulsatility, and have an increased risk of adverse events. A sensorless, physiologic feedback control strategy for RBP was developed to mitigate these limitations. The proposed algorithm used intrinsic pump speed to obtain differential pump speed (Δ). The proposed gain-scheduled proportional-integral controller, switching of setpoints between a higher pump speed differential setpoint (Δ ) and a lower pump speed differential setpoint (Δ ), generated pulsatility and physiologic perfusion, while avoiding suction. The switching between Δ and Δ setpoints occurred when the measured Δ reached the pump differential reference setpoint. In-silico tests were implemented to assess the proposed algorithm during rest, exercise, a rapid 3-fold pulmonary vascular resistance increase, rapid change from exercise to rest, and compared with maintaining a constant pump speed setpoint. The proposed control algorithm augmented aortic pressure pulsatility to over 35 mmHg during rest and around 30 mmHg during exercise. Significantly, ventricular suction was avoided, and adequate cardiac output was maintained under all simulated conditions. The performance of the sensorless algorithm using estimation was similar to the performance of sensor-based method. This study demonstrated that augmentation of vascular pulsatility was feasible while avoiding ventricular suction and providing physiological pump outflows. Augmentation of vascular pulsatility can minimize adverse events that have been associated with diminished pulsatility. Mock circulation and animal studies would be conducted to validate these results.
持续流动旋转式血泵（RBP）在临床以恒定转速运行时，无法在不同体力活动期间匹配心脏需求，易受吸力影响，会削弱血管搏动性，且不良事件风险增加。为减轻这些局限性，开发了一种用于RBP的无传感器生理反馈控制策略。所提出的算法利用泵的固有转速来获取泵速差（Δ）。所提出的增益调度比例积分控制器，在较高泵速差设定值（Δ ）和较低泵速差设定值（Δ ）之间切换设定点，产生搏动性和生理性灌注，同时避免吸力。当测量的Δ达到泵速差参考设定值时，在Δ 和Δ 设定点之间进行切换。进行了计算机模拟测试，以评估所提出的算法在静息、运动、肺血管阻力迅速增加3倍、从运动迅速转变为静息状态时的性能，并与维持恒定泵速设定点进行比较。所提出的控制算法在静息时将主动脉压力搏动性增强至超过35 mmHg，在运动时增强至约30 mmHg。重要的是，避免了心室抽吸，并且在所有模拟条件下均维持了足够的心输出量。使用估计的无传感器算法的性能与基于传感器的方法的性能相似。本研究表明，在避免心室抽吸并提供生理性泵输出的同时增强血管搏动性是可行的。增强血管搏动性可将与搏动性减弱相关的不良事件降至最低。将进行模拟循环和动物研究以验证这些结果。
