The present study was undertaken to clinically evaluate propofol and ketamine as induction agents for halothane anaesthesia, in dogs premedicated with midazolam and fentanyl. The study was conducted on 31 clinical cases of dogs, with 16 dogs in ketamine group and 15 dogs in propofol group. All dogs were atropinised and subsequently premedicated with 5 μg/kg fentanyl i/m, followed 30 minutes later with 0.3 mg/kg midazolam, i/v. Three minutes later the dogs were induced either with ketamine or propofol intravenously, and subsequently maintained on halothane in oxygen. The duration of surgical anaesthesia in the ketamine and propofol group was 66.79±5.73 and 68.08±6.09 minutes. The mean dose rates (mg/kg) of ketamine and propofol required for induction were 6.22±0.29 and 2.64±0.14 mg/kg, respectively, and the mean halothane per cent required for maintenance by ketamine group was 1.82±0.06, which was significantly lesser than that required by propofol group (1.99±006). Quality of induction in propofol group was significantly better than that observed in ketamine group. The time to intubation was shorter than ketamine group's, with the mean time to intubation being 160.71±21.90 seconds in the ketamine group and 66.92±8.20 seconds in the propofol group. Tachycardia was observed in both groups following induction, and cardiovascular function was maintained by both groups, although the propofol group was relatively more hypotensive than ketamine group. Haematological parameters (Hb, PCV and TLC) decreased in both groups in the post-induction period and blood glucose was elevated in both groups in post induction period. The mean recovery parameters between the groups did not vary and quality of recovery was comparable in both groups. It was concluded that the anaesthetic combination provided by both ketamine and propofol groups was comparable, although ketamine group was found to be more suitable for hypovolaemic patients; and propofol group was more favourable when rapid induction and intubation were necessary.
