Mansouri Mahdi, Salamonsen Robert F, Lim Einly, Akmeliawati Rini, Lovell Nigel H
Department of Biomedical Engineering, University of Malaya, Kuala Lumpur, Malaysia.
Department of Intensive Care, Alfred Hospital, Prahran, VIC, Australia; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia.
PLoS One. 2015 Apr 7;10(4):e0121413. doi: 10.1371/journal.pone.0121413. eCollection 2015.
In this study, we evaluate a preload-based Starling-like controller for implantable rotary blood pumps (IRBPs) using left ventricular end-diastolic pressure (PLVED) as the feedback variable. Simulations are conducted using a validated mathematical model. The controller emulates the response of the natural left ventricle (LV) to changes in PLVED. We report the performance of the preload-based Starling-like controller in comparison with our recently designed pulsatility controller and constant speed operation. In handling the transition from a baseline state to test states, which include vigorous exercise, blood loss and a major reduction in the LV contractility (LVC), the preload controller outperformed pulsatility control and constant speed operation in all three test scenarios. In exercise, preload-control achieved an increase of 54% in mean pump flow ([Formula: see text]) with minimum loading on the LV, while pulsatility control achieved only a 5% increase in flow and a decrease in mean pump speed. In a hemorrhage scenario, the preload control maintained the greatest safety margin against LV suction. PLVED for the preload controller was 4.9 mmHg, compared with 0.4 mmHg for the pulsatility controller and 0.2 mmHg for the constant speed mode. This was associated with an adequate mean arterial pressure (MAP) of 84 mmHg. In transition to low LVC, [Formula: see text] for preload control remained constant at 5.22 L/min with a PLVED of 8.0 mmHg. With regards to pulsatility control, [Formula: see text] fell to the nonviable level of 2.4 L/min with an associated PLVED of 16 mmHg and a MAP of 55 mmHg. Consequently, pulsatility control was deemed inferior to constant speed mode with a PLVED of 11 mmHg and a [Formula: see text] of 5.13 L/min in low LVC scenario. We conclude that pulsatility control imposes a danger to the patient in the severely reduced LVC scenario, which can be overcome by using a preload-based Starling-like control approach.
在本研究中，我们评估了一种基于前负荷的类斯塔林控制器，用于植入式旋转血泵（IRBP），该控制器使用左心室舒张末期压力（PLVED）作为反馈变量。使用经过验证的数学模型进行模拟。该控制器模拟天然左心室（LV）对PLVED变化的反应。我们报告了基于前负荷的类斯塔林控制器与我们最近设计的搏动性控制器和恒速运行相比的性能。在处理从基线状态到测试状态的转变时，测试状态包括剧烈运动、失血和左心室收缩力（LVC）大幅降低，前负荷控制器在所有三种测试场景中均优于搏动性控制和恒速运行。在运动时，前负荷控制使平均泵流量（[公式：见正文]）增加了54%，同时左心室的负荷最小，而搏动性控制仅使流量增加了5%，且平均泵速降低。在出血场景中，前负荷控制对左心室抽吸保持了最大的安全 margin。前负荷控制器的PLVED为4.9 mmHg，搏动性控制器为0.4 mmHg，恒速模式为0.2 mmHg。这与84 mmHg的充足平均动脉压（MAP）相关。在向低LVC转变时，前负荷控制的[公式：见正文]保持恒定在5.22 L/min，PLVED为8.0 mmHg。关于搏动性控制，[公式：见正文]降至2.4 L/min的不可行水平，相关的PLVED为16 mmHg，MAP为55 mmHg。因此，在低LVC场景中，搏动性控制被认为不如PLVED为11 mmHg、[公式：见正文]为5.13 L/min的恒速模式。我们得出结论，在LVC严重降低的场景中，搏动性控制对患者构成危险，而使用基于前负荷的类斯塔林控制方法可以克服这一危险。
