Evaluation of a two stage axial flow pump on hemolysis

Abstract

To reduce hemolysis in an axial flow pump (AP), a basic study of a two stage AP (2S) was performed. The 2S was evaluated in two kinds of in vitro hemolysis tests for four hours. In the first test, the 2S was compared with two kinds of single stage APs (1Ss). Each pump was designed to be operated at a flow rate of 5l/min and a pressure head of 100mmHg. The 2S was series operation of two single stage APs designed at a flow rate of 5l/min and a pressure head of 50mmHg. One of the 1Ss has the same specific speed (Ns) of the 2S and the other 1S has the same impeller of the single stage of the 2S. In the second test, hemolysis in each stage of the 2S was evaluated. The basic structure of all single stage APs were same. Allen's hemolytic Index (HI) of the 2S, that was regarded as an aggregate HI of both stage AP, was less than those of the iSs. These data suggests that the 2S was useful to reduse hemolysis in an AP.