Change of platelet functions during cardiopulmonary bypass

For observing the activation degree of platelets during various stages of cardiopulmonary bypass (CPB), a monoclonal antibody SZ-51 specific for an α-granule membrane protein (GMP-140) on the surface of activated human platelets was used. The number of platelets fell significantly during CPB and went to minimum at the end of CPB. The GMP-140 molecules on the platelet surface remarkably increased at the start of CPB, then reached to maximum between the ending of CPB and administration of protamine, and returned to normal 2 hours post-operation. However, after ending of CPB the concentration of GMP-140 in plasma began to increase, 2 hours post-operation reached to peak and 24 to 48 hours after ending CPB returned to normal. The TxB2 in plasma reached the first peak after heparinization and start of CPB, the second peak was in the end of CPB and after administration of protamine, and returned to normal 2 hours post-operation. But the 6-keto-PGF1α did not change very much. The concentration of PF4 increased at the start of CPB reached to peak at the end of CPB and became normal 24 hours post-operation. The vWF increased at the start of CPB and reached to peak at the ending of CPB, then returned to normal 24 hours post-operation. These results could explain the activation degree of platelets during CPB