Mason David G, Hilton Andrew K, Salamonsen Robert F
Department of Surgery, Monash University, Melbourne, Australia.
ASAIO J. 2008 Jul-Aug;54(4):359-66. doi: 10.1097/MAT.0b013e31817b5b0e.
All rotary blood pumps (RBPs) are prone to the harmful effects of ventricular collapse or "suction events" because of over-pumping, because they are inherently preload insensitive devices, yet RBP controllers do not comprise a clinically reliable suction detector. We therefore investigated the clinical performance of seven expertly selected time domain indices of suction based on the observed positive spike induced in the RBP impeller speed waveform. Using expert panel classifications, a balanced set of 404 five-second speed snapshots of normal and suction events was created from the impeller speed 25 Hz data in 12 VentrAssist implant patients. Initially, suction index threshold levels were set differently for each patient, giving best sensitivity 95% and specificity 99%. However, analysis of paired combinations of suction indices with fixed thresholds identified one pair giving an acceptable sensitivity of 99.5% and specificity 97.5%; the low number of high speed data samples relative to the speed snapshot mean and maximum OR the largest increase in successive speed maxima. The additional precondition of RBP speed amplitude exceeding a low threshold level allows its more general application to patients with low cardiac contractility. This gives a suction detector with high clinical utility; requiring three index threshold settings only.
由于过度泵血，所有旋转血泵（RBP）都容易受到心室塌陷或“抽吸事件”的有害影响，因为它们本质上是对前负荷不敏感的装置，然而RBP控制器并不包含临床上可靠的抽吸检测器。因此，我们基于在RBP叶轮速度波形中观察到的正向尖峰，研究了七个精心挑选的抽吸时域指标的临床性能。利用专家小组分类，从12名VentrAssist植入患者的叶轮速度25Hz数据中创建了一组平衡的404个五秒正常和抽吸事件速度快照。最初，为每位患者设置不同的抽吸指数阈值水平，最佳灵敏度为95%，特异性为99%。然而，对具有固定阈值的抽吸指数配对组合进行分析后，确定了一对组合，其灵敏度为99.5%，特异性为97.5%，可接受；相对于速度快照平均值和最大值，高速数据样本数量较少，或者连续速度最大值的最大增加量。RBP速度幅度超过低阈值水平这一附加前提条件使其更普遍地适用于心脏收缩力低的患者。这就产生了一种具有高临床实用性的抽吸检测器；仅需要三个指数阈值设置。
