Platelet function tests during major operation for gastro-intestinal carcinoma.

Platelet function tests were performed on 15 patients undergoing major operation preoperatively, during anaesthesia and 30 minutes and 3 hours after the beginning of operation. It was found that during anaesthesia platelet retention in a glass bead column and platelet aggregation were slightly reduced. During operation the bleeding time and the delay period of the collagen-induced aggregation were progressively prolonged, and the aggregation induced by ADP at a final concentration of 1 and 2 micrometer and by adrenaline was progressively reduced.