Karantonis Dean M, Lovell Nigel H, Ayre Peter J, Mason David G, Cloherty Shaun L
Graduate School of Biomedical Engineering, University of New South Wales, Sydney NSW, Australia.
Artif Organs. 2006 Sep;30(9):671-9. doi: 10.1111/j.1525-1594.2006.00283.x.
In a clinical setting it is necessary to control the speed of rotary blood pumps used as left ventricular assist devices to prevent possible severe complications associated with over- or underpumping. The hypothesis is that by using only the noninvasive measure of instantaneous pump impeller speed to assess flow dynamics, it is possible to detect physiologically significant pumping states (without the need for additional implantable sensors). By varying pump speed in an animal model, five such states were identified: regurgitant pump flow, ventricular ejection (VE), nonopening of the aortic valve over the cardiac cycle (ANO), and partial collapse (intermittent and continuous) of the ventricle wall (PVC-I and PVC-C). These states are described in detail and a strategy for their noninvasive detection has been developed and validated using (n = 6) ex vivo porcine experiments. Employing a classification and regression tree, the strategy was able to detect pumping states with a high degree of sensitivity and specificity: state VE-99.2/100.0% (sensitivity/specificity); state ANO-100.0/100.0%; state PVC-I- 95.7/91.2%; state PVC-C-69.7/98.7%. With a simplified binary scheme differentiating suction (PVC-I, PVC-C) and nonsuction (VE, ANO) states, both such states were detected with 100% sensitivity.
在临床环境中，有必要控制用作左心室辅助装置的旋转血泵的速度，以防止与泵血过多或过少相关的可能严重并发症。假设是，通过仅使用瞬时泵叶轮速度的非侵入性测量来评估血流动力学，有可能检测出生理上显著的泵血状态（无需额外的植入式传感器）。通过在动物模型中改变泵速，确定了五种这样的状态：泵反流、心室射血（VE）、心动周期中主动脉瓣未打开（ANO）以及心室壁部分塌陷（间歇性和持续性）（PVC-I和PVC-C）。详细描述了这些状态，并使用（n = 6）离体猪实验开发并验证了一种用于非侵入性检测它们的策略。采用分类回归树，该策略能够以高度的敏感性和特异性检测泵血状态：VE状态为99.2/100.0%（敏感性/特异性）；ANO状态为100.0/100.0%；PVC-I状态为95.7/91.2%；PVC-C状态为69.7/98.7%。采用区分抽吸（PVC-I、PVC-C）和非抽吸（VE、ANO）状态的简化二元方案，两种状态的检测敏感性均为100%。
