EFFECTS OF 2 INJECTABLE ANESTHETIC AGENTS ON COAGULATION ASSAYS IN THE RAT

The rat is commonly used as an animal model to test the efficacy of ne w anticoagulant and antithrombotic drugs. Many of the protocols requir e the use of anesthetics for surgical procedures, Three common coagula tion assays used to monitor the effects of new anticoagulant and antit hrombotic drugs are thrombin time, activated partial thromboplastin ti me, and prothrombin time. We examined the effects of either urethane- or ketamine/xylazine-induced anesthesia on variables in the three coag ulation assays with blood samples obtained from the rats before the in duction of anesthesia, compared with samples obtained at 15 or 60 min after anesthesia induction, Statistically significant differences were observed in the ketamine/xylazine group for thrombin time at 60 min ( compared with control values) and in the urethane group for activated partial thromboplastin time at 60 min (compared with control values). in both instances a prolongation of times vas the effect seen. These r esults indicate that the choice of anesthetic affects the data in cert ain coagulation assays in the rat and must be taken into account when one is planning studies and analyzing results.