Wang Yu, Koenig Steven C, Slaughter Mark S, Giridharan Guruprasad A
From the Department of Bioengineering and Cardiovascular and Thoracic Surgery, Cardiovascular Innovation Institute, University of Louisville, Louisville, Kentucky.
ASAIO J. 2015 Jan-Feb;61(1):21-30. doi: 10.1097/MAT.0000000000000152.
The risk for left ventricular (LV) suction while maintaining adequate perfusion over a range of physiologic conditions during continuous flow LV assist device (LVAD) support is a significant clinical concern. To address this challenge, we developed a suction prevention and physiologic control (SPPC) algorithm for use with axial and centrifugal LVADs. The SPPC algorithm uses two gain-scheduled, proportional-integral controllers that maintain a differential pump speed (ΔRPM) above a user-defined threshold to prevent LV suction, while maintaining an average reference differential pressure (ΔP) between the LV and aorta to provide physiologic perfusion. Efficacy and robustness of the proposed algorithm were evaluated in silico during simulated rest and exercise test conditions for (1) ΔP/ΔRPM excessive setpoint (ES); (2) rapid eightfold increase in pulmonary vascular resistance (PVR); and (3) ES and PVR. Hemodynamic waveforms (LV pressure and volume; aortic pressure and flow) were simulated and analyzed to identify suction event(s), quantify total flow output (pump + cardiac output), and characterize the performance of the SPPC algorithm. The results demonstrated that the proposed SPPC algorithm prevented LV suction while maintaining physiologic perfusion for all simulated test conditions, and warrants further investigation in vivo.
在连续流左心室辅助装置（LVAD）支持期间，在一系列生理条件下维持充足灌注时左心室（LV）抽吸的风险是一个重大的临床问题。为应对这一挑战，我们开发了一种用于轴流和离心式LVAD的防抽吸和生理控制（SPPC）算法。SPPC算法使用两个增益调度的比例积分控制器，将泵速差（ΔRPM）维持在用户定义的阈值以上以防止LV抽吸，同时维持LV与主动脉之间的平均参考压差（ΔP）以提供生理灌注。在模拟静息和运动测试条件下，通过计算机模拟评估了所提出算法对于以下情况的有效性和鲁棒性：（1）ΔP/ΔRPM过高设定值（ES）；（2）肺血管阻力（PVR）快速增加八倍；（3）ES和PVR。模拟并分析了血流动力学波形（LV压力和容积；主动脉压力和流量），以识别抽吸事件、量化总流量输出（泵流量+心输出量）并表征SPPC算法的性能。结果表明，所提出的SPPC算法在所有模拟测试条件下均能防止LV抽吸，同时维持生理灌注，值得在体内进行进一步研究。
