A NEW MAGNETICALLY SUSPENDED CENTRIFUGAL PUMP - IN-VITRO AND PRELIMINARY IN-VIVO ASSESSMENT

To overcome problems derived from the shaft within the conventional ce ntrifugal pump, we have been developing a new centrifugal pump, namely a magnetically suspended centrifugal pump (MSCP), which has no shaft and operates as a noncontacting and bearingless pump, The impeller is suspended magnetically between the magnetic bearing and the driving mo tor. Hemolysis tests were performed in comparison with the Biopump (BP 80, BioMedicus). The index of hemolysis (IH) was significantly lower i n the MSCP than in the Biopump. In addition, a smaller gap in the MSCP induced lower hemolysis. In preliminary studies using mongrel dogs, t he layer of thrombus adherent to the impeller was observed in a few ho urs, which impaired the pumping efficiency. However, by using an impel ler coated with silicone, no aggregations of platelets or fibrin on th e impeller were observed in 24 h of continuous pumping. In conclusion, the MSCP had a gentler influence on blood cells than the Biopump, and the impeller coated with silicone may contribute to the long-term pum ping of the MSCP.