Wakisaka Y, Okuzono Y, Taenaka Y, Chikanari K, Masuzawa T, Takano H
Department of Artificial Organs, National Cardiovascular Center Research Institute, Osaka, Japan.
ASAIO J. 1997 Sep-Oct;43(5):M659-62.
A less invasive and non thrombogenic flow estimation of an implantable centrifugal blood pump (ICBP) has been developed, which was derived from electric power consumption, the rotating speed of a motor, and blood viscosity presumed by hematocrit and body temperature. The power consumption and the rotating speed of the motor were measured by a wattmeter every 0.2 sec. Accuracy and stability of the estimated flow (EF) were investigated during in vitro and in vivo experiments. The EF was compared with a measured flow rate (MF) monitored by an electromagnetic flowmeter. During in vitro experiments, the EF and MF were measured at 79 operating points. The ICBP was driven in a closed mock loop filled with goat blood with hematocrit values of 21.5, 28, 34, and 42%. During in vivo experiments, the ICBP was implanted in the chest cavity of a goat and driven for 40 days with continuous estimation of the bypass flow rate. Blood was taken to determine hematocrit value several times a week. The temperature of the pleura away from the ICBP was measured every 15 min. A linear correlation between the EF and MF was observed, and the correlation coefficient between the EF and MF was 0.99 during in vitro examinations. An averaged error of the EF was 0.5 L/min, with the MF ranging from 2.3 to 8.1 L/min during in vivo experiments. In conclusion, flow estimation was established with good stability and accuracy in both in vitro and in vivo experiments.
已开发出一种对植入式离心血泵（ICBP）进行侵入性较小且无血栓形成的流量估计方法，该方法源自电能消耗、电机转速以及由血细胞比容和体温推测出的血液粘度。通过功率计每0.2秒测量一次电能消耗和电机转速。在体外和体内实验中研究了估计流量（EF）的准确性和稳定性。将EF与电磁流量计监测的测量流量（MF）进行比较。在体外实验中，在79个工作点测量了EF和MF。ICBP在充满血细胞比容值分别为21.5%、28%、34%和42%的山羊血液的封闭模拟回路中驱动。在体内实验中，将ICBP植入山羊胸腔并驱动40天，同时持续估计旁路流量。每周多次采集血液以测定血细胞比容值。每隔15分钟测量一次远离ICBP的胸膜温度。在体外检查期间，观察到EF和MF之间存在线性相关性，EF和MF之间的相关系数为0.99。在体内实验中，EF的平均误差为0.5升/分钟，MF范围为2.3至8.1升/分钟。总之，在体外和体内实验中均建立了具有良好稳定性和准确性的流量估计方法。
