Ketamine infusion for postoperative analgesia: a prospective cohort study in asthmatics.

Ketamine, most often used as an anaesthetic agent can provide adequate post operative analgesia when delivered in the form of infusion, replacing narcotics, which can cause bronchospasm in susceptible individuals. This cohort study was undertaken to assess the feasibility of providing complete post operative analgesia in asthmatics with ketamine delivered in sub-anaesthetic doses (6.10-6.41 ugm./kg.-1/min-1). Diazepam (0.97-1.02 ugm./kg.-1/min-1) was delivered from the same infusion to eliminate the unwanted effects of ketamine. Ketamine induced little alteration in blood pressure while tachycardia was significant (P < 0.05). Respiratory functions observed, were favourable for asthmatics. Diazepam helped in reducing ketamine induced side effects, but after infusion over long periods tendency of cumulation was observed. Complications encountered were minimum with more than 93% patient acceptability for this method of analgesia.