Hemocompatibility of a Centrifugal Pump for a Portable Hemofiltration System

Almost all pumps for presently available blood purification systems are roller pumps. If a small centrifugal blood pump is developed and a vascular access to peripheral vein is realized, it would be possible to downsize the hemofiltration systems for transportation. We have developed centrifugal pumps, DP2 and DP3, whose impeller diameters are 30 mm and are supported with a monopivot bearing. These pumps provide stable blood flow even at 50 mL/min. The hemocompatibility has been investigated in the present study. The hemolysis level of DP2 was found to be a quarter of a commercial extracorporeal centrifugal pump and that of DP3 was 1/20 times. It was also found that the prevention of pivot wear is important to keep the low hemolysis level. An in vitro thrombogenicity test using bovine blood revealed that the observed thrombus around the pivot bearing was small enough to be trapped in a filter.