The spindle pump. Development of a nonpulsatile blood pump for assisted circulation

The spindle pump is a combined working nonpulsatile blood pump, i.e., a centrifugally propelling device. This special concept was chosen to tackle the main problems of nonpulsatile pumps, such as thromboembolic complications, sealing difficulties, and traumatic hemolysis. The first two of these problems were relatively simple to solve compared with the third problem--traumatic hemolysis. Various modifications and constructive steps of the spindle pump were necessary to keep stress on blood components within adequate limits. The actual prototype--tested in three acute experiments and eight experiments with a longer pumping duration (the longest lasting 63 hours)--is described in extenso, and its development is discussed.