EFFECTS OF TROMETHAMINE BUFFER ON COAGULATION VARIABLES AND IONIZED CALCIUM-CONCENTRATION IN DOGS

Objective-To evaluate coagulation variables in 2 groups of dogs after tromethamine administration. Animals-13 Beagles. Procedures-Both group s of dogs received a 30-minute IV infusion of 10 ml of 0.3 M trometham ine/kg of body weight. In unsedated dogs (group 1, n = 8), prothrombin time, activated partial thromboplastin time, normalized ionized calci um concentration, platelet numbers, and platelet function were measure d prior to treatment, at the end of the infusion, and 1 hour after the infusion. In xylazine-sedated dogs (group 2, n = 5), buccal mucosal b leeding time and plasma percentage of von Willebrand factor antigen we re measured before and 1 hour after infusion, and fibrin degradation p roducts concentration was measured 1 hour after infusion. Platelet fun ction was assessed by determining platelet aggregation and by measurin g ATP release from the aggregating platelets over 6 minutes, using a w hole blood aggregometer, with 20, 10, and 5 mu M ADP and 5 and 10 mu g of collagen/ml as platelet activation agonists. Results-There was no significant change in any of the variables measured in either group of dogs, compared with baseline values. Conclusions and Clinical Relevan ce-When administered to healthy dogs, tromethamine does not change the coagulation indices measured.