Haemolytic index and performance of a magnetically coupled rotary pulsatile pump with potential for ventricular...

A novel magnetically coupled rotary vane pump is described which has the potential to be used as a ventricular assist device. The pump has an excellent haemodynamic performance. When tested, pumping blood, against a range of pressures from 20 to 100 mm Hg the volumetric output varied within reasonable limits. The pump could deliver 5.1 litres per minute against a pressure of 180 mm Hg before the magnetic coupling disengaged. With specially moulded magnets improved coupling can be achieved. The haemolytic index was determined using a circuit conforming to ASTM: F04-40-101. The NIH (normalised index of haemolysis) was found to be 0.3 and the MIH (modified index of haemolysis) 0.26 which is unacceptably high for long term perfusion. The pump has several outstanding features, it is hermetically sealed, it needs no valving, a desirable property in a ventricular assist pump, and it has a pulsatile action. In a non magnetically coupled form it performed satisfactorily in left ventricular assist mode and as a total cardiopulmonary bypass pump in short term experiments with dogs.