THE EFFECT OF VALVE TYPE AND DRIV ELINE DP DT ON HEMOLYSIS IN THE PNEUMATIC VENTRICULAR ASSIST DEVICE/

The objective of this experiment was to investigate the relationship b etween blood damage and drive line dP/dt and valve type in the pneumat ic ventricular assist device. Two mock circulatory loops were assemble d using 70 ml Penn State pneumatic ventricular assist devices, one fit ted with convexoconcave (CC) valves and one fitted with monostrut (MS) valves. Use of a compliance chamber established three ranges of drive line dP/dt values. Using bovine blood and the methods of generalized estimating equations, it was found that drive line dP/dt was significa ntly associated with the index of hemolysis (p = 0.00): the lower driv e line dP/dt values yielded lower indices of hemolysis. In addition, t his association differed between MS and CC valves (p = 0.01); the MS v alves consistently yielded a higher index of hemolysis than the CC val ves across all drive line dP/dt ranges. However, the relative hemolyti c potential of each valve type became much closer at low drive line dP /dt values (2,000-3,000 mm Hg).