Hemolytic effect of the secondary vane incorporated into the back side of the impeller

The hemolytic effect of the secondary vane system, the antithrombogenic structure incorporated into the back side of the impeller of the C1E3 Gyro pump, was investigated. Impellers with 0, 2, 3, and 4 secondary vanes and an additional impeller with 2 secondary channels were fabricated and incorporated into the C1E3 pump casings. Hemolysis tests were performed under cardiopulmonary bypass conditions (flow rate 4.5 L/min, total pressure head 350 mm Hg) using flesh bovine blood. The normalized indices of hemolysis (NIH) of the pumps with 0, 2, 3, and 4 secondary vanes and the pump with 2 secondary channels were 0.0797, 0.0866, 0.104, 0.157, and 0.0591, respectively. These results indicated that design of the impeller with 2 secondary channels, which was the original design of C1E3 Gyro pump, was less hemolytic than the design with secondary vanes. Additionally, the possibility of the secondary channel system for the impeller bottom was demonstrated favorably.