Stevens Michael Charles, Gaddum Nicholas Richard, Pearcy Mark, Salamonsen Robert F, Timms Daniel Lee, Mason David Glen, Fraser John F
School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Australia.
Annu Int Conf IEEE Eng Med Biol Soc. 2011;2011:1335-8. doi: 10.1109/IEMBS.2011.6090314.
A physiological control system was developed for a rotary left ventricular assist device (LVAD) in which the target pump flow rate (LVADQ) was set as a function of left atrial pressure (LAP), mimicking the Frank-Starling mechanism. The control strategy was implemented using linear PID control and was evaluated in a pulsatile mock circulation loop using a prototyped centrifugal pump by varying pulmonary vascular resistance to alter venous return. The control strategy automatically varied pump speed (2460 to 1740 to 2700 RPM) in response to a decrease and subsequent increase in venous return. In contrast, a fixed-speed pump caused a simulated ventricular suction event during low venous return and higher ventricular volumes during high venous return. The preload sensitivity was increased from 0.011 L/min/mmHg in fixed speed mode to 0.47L/min/mmHg, a value similar to that of the native healthy heart. The sensitivity varied automatically to maintain the LAP and LVADQ within a predefined zone. This control strategy requires the implantation of a pressure sensor in the left atrium and a flow sensor around the outflow cannula of the LVAD. However, appropriate pressure sensor technology is not yet commercially available and so an alternative measure of preload such as pulsatility of pump signals should be investigated.
开发了一种用于旋转式左心室辅助装置（LVAD）的生理控制系统，其中目标泵流量（LVADQ）根据左心房压力（LAP）设置，模拟了Frank-Starling机制。该控制策略采用线性PID控制实现，并在脉动模拟循环回路中使用原型离心泵进行评估，通过改变肺血管阻力来改变静脉回流。控制策略会根据静脉回流的减少和随后的增加自动改变泵速（2460至1740至2700转/分钟）。相比之下，固定速度泵在低静脉回流时会导致模拟心室抽吸事件，在高静脉回流时会导致心室容积增加。预负荷敏感性从固定速度模式下的0.011升/分钟/毫米汞柱提高到0.47升/分钟/毫米汞柱，这一数值与健康的天然心脏相似。敏感性会自动变化以将LAP和LVADQ维持在预定义区域内。这种控制策略需要在左心房植入压力传感器，并在LVAD流出插管周围植入流量传感器。然而，合适的压力传感器技术尚未商业化，因此应研究诸如泵信号脉动性等预负荷的替代测量方法。
