We have studied the effect of ketamine induction on ventilation at three regiment premedications. Forty five patients (ASA 1) were allocated randomly into three experimental groups, comparable in age, height and weight, to receive one of the regiment premedication : a combination of 1 mg/kg.bw pethidine + 0.5 mg atropine; 2.5 mg Droperidol + 0.5 atropine or 1 mg/kg. bw pethidine + 2.5 mg Droper…