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.