Evaluation of the effect of I. M. lignocaine or bupivacaine on the hypnotic requirements of ketamine and propofol

ABSTRACT

We have studied the effect of i.m. lignocaine or bupivacaine on the hypnotic requirements of Ketamine and propofol in sixty patients of ASA I and II undergoing minor elective surgery under general anaesthesia. These patients were allocated randomly into two groups, ketamine group and propofol group. Each group was further subdivided into 3 subgroups A, B and C [n = 10 for each subgroup] where patients received saline, lignocaine or bupivacaine i.m. respectively before induction of anaesthesia. Anaesthesia was induced by ketamine or propofol in bolus doses of 0.2 mg/Kg every 30 sec. until loss of verbal response to verbal command was achieved. We found that lignocaine and bupivacaine significantly reduced the hypnotic doses of ketamine by 39.7% and 32.6% and that of propofol by 25.9% and 30.8% respectively. We concluded that the hypnotic doses of i.v. ketamine or propofol should be reduced if their administration is preceded by lignocaine or bupivacaine