Ayre P J, Vidakovic S S, Tansley G D, Watterson P A, Lovell N H
VentrAssist, University of Technology, and University of New South Wales, Sydney, Australia.
Artif Organs. 2000 Aug;24(8):585-8. doi: 10.1046/j.1525-1594.2000.06586.x.
Flow rate and pressure difference (or head) are key variables needed in the control of implantable rotary blood pumps. However, use of flow and/or pressure probes can decrease reliability and increase system power consumption and expense. For a given fluid viscosity, the flow state is determined by any 2 of the 4 pump variables: Flow, pressure difference, speed, and motor input power can be used. Thus, if viscosity is known or if its influence is sufficiently small, flow rate and pressure difference can be estimated from the motor speed and motor input power. For the VentrAssist centrifugal blood pump, which uses a hydrodynamic bearing, sensorless flow and pressure head estimation accuracy of 2 of our impeller designs were compared for a viscosity range of 1.2 to 4.5 mPas. This showed impeller design optimization can improve estimation accuracy. We also compared estimation accuracy using 2 blood analogues used in vitro, aqueous glycerol and red blood cells suspended in Haemaccel. The nature of the blood analogue and not only the viscosity of the fluid seems to influence estimation accuracy in our pump.
流速和压差（或压头）是可植入旋转血泵控制中所需的关键变量。然而，使用流量和/或压力探头会降低可靠性，并增加系统功耗和成本。对于给定的流体粘度，流动状态由泵的四个变量中的任意两个决定：流量、压差、转速和电机输入功率均可使用。因此，如果粘度已知或其影响足够小，则可以根据电机转速和电机输入功率来估算流速和压差。对于采用流体动力轴承的VentrAssist离心血泵，在1.2至4.5毫帕斯卡的粘度范围内，比较了我们两种叶轮设计的无传感器流量和压头估计精度。结果表明，叶轮设计优化可提高估计精度。我们还比较了使用两种体外血液模拟物（甘油水溶液和悬浮在贺斯中的红细胞）时的估计精度。在我们的血泵中，似乎不仅流体的粘度，而且血液模拟物的性质也会影响估计精度。
