Abstract
For a cardiopulmonary support system with a membrane oxygenation such as a percutaneous cardiopulmonary support (PCPS) or an extracorporeal membrane oxygenation (ECMO), a blood pump needs to generate the pressure rise of approximately 200mmHg or higher, due to the high hydraulic resistances of the membrane oxygenation and of the cannula tubing. Using existent single stage rotary pumps with higher pressure rise result in the higher rotational speed of the pumps and possibly lead to the higher amount of hemolysis due to the larger shear stress acting on blood cells. In order to realize a blood pump with higher pressure rise, higher anti-hemolysis and thrombosis performances, the development of novel centrifugal blood pump consisting of two-stage has been conducted by the authors. As the conditions when the hemolysis and thrombosis occur are not clear and the type number of blood pumps is quite small, the design method of blood pumps has not been established yet. In the present paper, effective attempts to decrease the wall shear stress and to suppress the stagnation are introduced for the prevention of hemolysis and thrombosis in blood pumps. The hemolysis test was also carried out and it was clarified that the decrease of wall shear stress is effective as a guideline of design of blood pumps for improving the anti-hemolysis performance.
