IN-VITRO PERFORMANCE OF A CENTRIFUGAL, A MIXED-FLOW, AND AN AXIAL-FLOW BLOOD PUMP

We specially devised 3 types of turbo pumps, a centrifugal pump (CFP), a mixed flow pump (MFP), and an axial flow pump (AFP), and analyzed t heir in vitro performance. The common structural design elements were an impeller diameter of 20 mm and sealless magnet couple driving. In v itro tests were carried out using heparinized fresh bovine blood. The hemolysis was comprehensively evaluated at 7-16 points by changing the flow rate and pressure head (mapping of hemolytic property), The maxi mum efficiency (motor output to pump output) was 44.9% at 7,000 rpm. 3 .17 L/min, 191 mm Hg in the CFP; 66.3% at 7,000 rpm, 6.9 L/min, 136 mm Hg in the MFP; and 20.6% at 9,000 rpm, 5.54 L/min, 74 mm Hg in the AF P, respectively. The minimum normalized index of hemolysis (NIH) (g/10 0 L) was 0.038 at 5,000 rpm, 4.60 L/min, 38 mm Hg in the CFP; 0.010 at 7,000 rpm, 8.22 L/min, 100 mm Hg in the MFP; and 0.033 at 7,000 rpm, 2.84 L/min, 48 mm Hg in the AFP, respectively. The best efficiency and NIH were achieved in the MFP.