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ASAIO CARDIAC ABSTRACT

DIFFERENT LEVELS OF HEMOLYSIS OCCURRED BY A CENTRIFUGAL BLOOD PUMP IN VARIOUS CLINICAL CONDITIONS

Yuri, K1; Iwahashi, H1; Motomura, T1; Hata, A1; Asai, T1; Nose, Y1′; Arora, D2; Behr, M2,3; Pasquali, M1

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Purpose: The Gyro PI 710 implantable centrifugal pump with hydraulically levitated impeller is intended for long-term hi-ventricular assistance. While in clinical use the pump is commonly operated in vertical-or horizontal-impeller axis configuration. Also, the impeller axis may or may not be hydraulically levitated. Therefore, in each of these clinical configurations, the hemolysis characteristics were studied. Method: All hemolysis tests were performed while operating the pump at 5 L/min and 100 mm Hg pressure head. Also, the blood flow in the pump in the various configurations was calculated by computational fluid dynamics. The index of hemolysis was predicted using a new model which estimates cumulative RBC deformation due to fluid shear. The hemolysis is computed either along selected path lines (simpler) or at all locations in the flow field. Results: The Normalized Index of Hemolysis (NIH) in horizontal axis configuration with and without levitation was 0.0071 ±0.0016 and 0.0043±0.0014, while the corresponding vertical configuration was 0.0124 ± 0.0069 and 0.0119±0.0048 g/100L. This was significantly different between the horizontal-impeller axis and vertical-impeller axis without levitation (p<0.05). These results suggest that hemolysis is dependent on the orientation of the impeller. These model predictions can also be compared to these results.

Copyright © 2004 by the American Society for Artificial Internal Organs