HEMOLYSIS TEST OF A CENTRIFUGAL PUMP IN A PULSATILE MODE - THE EFFECTOF PULSE-RATE AND RPM VARIANCE

Centrifugal pumps are generally employed as nonpulsatile blood flow pu mps; however, these pumps can produce pulsatile flow by periodically a lternating the impeller rotation speed, This study investigates blood trauma due to the effect of pulse frequency and various ranges of pump speed. The hemolysis tests were conducted using the Gyro C1E3 pump. T he study was divided into the following categories: Group 1 in a nonpu lsatile mode: Group 2 operated at 40 bpm with 30% of speed variance; G roup 3, 60 bpm with 30% of speed variance: Group 4, 40 bpm with 70% of speed variance; and Group 5, 60 bpm with 70% of speed variance. A flo w rate of 3 L/min and a total pressure head of 200 mm Hg were employed in all groups to simulate a percutaneous cardiopulmonary support cond ition. There were no significant differences in the hemolysis levels a mong Groups 1, 2, and 3. However, Groups 4 and 5 exhibited a significa ntly higher hemolysis rate compared to the other groups. These results indicate that a high rate of speed variance increases hemolysis: howe ver, a range of less than 30% does not affect hemolysis. The pulse rat e has no significant effect on hemolysis. In conclusion, the higher sp eed variance increases the hemolysis level when a pulsatile mode is ap plied with a centrifugal pump at the given test conditions. However, a speed variance of less than 30% or a pulse rate of less than 60 bpm d oes not affect hemolysis.