2015 年 23 巻 1 号 p. 171-178
A novel blood pump with magnetically levitated impeller has been developed to recover cardiac function of acute heart failure patients. The pump assists patients' heart and the impeller's rotational speed are changed based on synchronizing with heart beat in order to increase coronary flow of patients' heart. Impeller levitation stability of the pump operated in pulsatile mode was evaluated with a mock circuit filled with water. In the pulsatile mode, the rotational speed was changed from 800 rpm to 1800 rpm with a beat rate of 60 bpm. Maximum axial displacement of the impeller is 22 % of the blood gap between the impeller and casing. Characteristics of hemolysis of the pump were examined within in-vitro hemolysis tests. NIH value of the maglev pump is about half time of it of a commercial based extracorporeal pump in constant speed operation. Even NIH value operated in the pulsatile mode is about two times of the commercial based pump's one and it is acceptable range for clinical usage. The developed maglev pump indicates sufficient impeller levitation stability and hemolysis property.