RESUMO
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