Development of a magnetically suspended centrifugal pump as a cardiac assist device for long-term application.
To overcome problems with the shaft seal in conventional centrifugal pumps, the authors have been developing a magnetically suspended centrifugal pump (MSCP) that operates as a valveless, sealless, and bearingless pump. The prototype of the MSCP was modified with respect to size of the volute diffuser and impeller blade profiles. A hemolysis test in vitro using a new version of the MSCP was performed in comparison with a commercially available centrifugal pump. The test circuit for the hemolysis test comprised a blood reservoir, a pump, and polyvinyl tubes, and was filled with fresh heparinized bovine blood. The pumping conditions were a flow rate of 5 L/min and a pump head afterload of 100 mmHg. The index of hemolysis in the MSCP was significantly lower than that in the Biomedicus pump (0.0035 +/- 0.0025 versus 0.0097 +/- 0.0056 g/100 L, p < 0.05). Reduction in the platelet count during pumping also was lower in the MSCP compared with the Biomedicus pump at both 6 hrs and 12 hrs of pumping (p < 0.01). This MSCP may be advantageous for extended use of assist devices, not only from the theoretical point of view, but in a practical sense after the results of the current hemolysis test.
Nishimura
K
K
Department of Cardiovascular Surgery and Mechanical Engineering, Kyoto University, Japan.
Park
C H
CH
Akamatsu
T
T
Yamada
T
T
Ban
T
T
D002498:Centrifugation / Q000295:instrumentation; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D006353:Heart-Assist Devices / Q000009:adverse effects; D006461:Hemolysis; D006801:Humans; D066298:In Vitro Techniques; D008280:Magnetics; D010976:Platelet Count; D013921:Thrombocytopenia / Q000517:prevention & control