NONINVASIVE PUMP FLOW ESTIMATION OF A CENTRIFUGAL BLOOD PUMP

A flow rate estimating method was investigated for a centrifugal blood pump developed in our institute. The estimated flow rate was determin ed by the power consumption, the rotating speed of the motor, and the hematocrit value. The power consumption and the rotating speed of the motor were measured with a wattmeter. The examinations were performed in a closed mock loop filled with goat blood with hematocrit values of 21.5%, 28%, 34%, and 42%. Measured values of blood viscosity were 2.4 7, 3.09, 3.71, and 5.07 mPa . s at a share rate of 37.5/s, respectivel y. A linear correlation between the power consumption and the pump flo w rate was observed in all hematocrit values. But variations in hemato crit caused a difference in the flow rate up to 1.1 L/min at the same power consumption and rotating speed. Effects of blood viscosity on th e flow estimation were corrected by the hematocrit value. The value of the coefficient of determination, RP between the estimated flow rate and the measured now rate was 0.988. These results may indicate that t he now estimating method calculated by the power consumption of the mo tor, the rotating speed, and the hematocrit value is useful in the cli nical situation.