PLATELET-FUNCTION ANALYSIS AFTER IN-VITRO TREATMENT WITH HEMOSTASIS-AFFECTING COMPONENTS

An overall platelet function test in whole blood, which simulates cond itions under arterial pressure, is useful in measuring the effect of p olymer materials on blood hemostatic function. We performed biocompati bility tests with materials or plasma substitutes by interaction of bl ood from healthy volunteers and then subjected these blood samples to platelet function analysis (Thrombostat). We tested also the capacity of locally applied hemostatic agents for bleeding control by direct ap plication of these agents onto the Thrombostat measuring cell. The bio compatibility tests with materials exposed to blood appeared very disc riminating between compatible and noncompatible materials. The hemosta tic capacity of blood exposed to noncompatible materials (assessed by binding of active thrombin) reduced markedly after one hour incubation of the material. The plasma substitutes did not affect hemostasis sig nificantly. However, a blood dilution of 40%, as in cardiopulmonary by pass, increased the time required for closure of the measuring cell by a platelet plug exponentially. Local hemostatic agents could be selec ted according to their capacity to enhance platelet plug formation. In addition, ADP mixed with the hemostatic agent was most effective in i mproving capacity. We conclude that platelet function analysis contrib utes importantly to screening of materials and plasma substitutes with regard to their interaction with primary hemostasis.