Effect of dexmedetomidine with or without butorphanol on the clinico-physiological and haemodynamic stability in dogs undergoing ovariohysterectomy in midazolam and ketamine anaesthesia

Clinical anaesthetic trial was conducted in mixed breed dogs undergoing ovariohysterectomy to observe the effect of dexmedetomidine and dexmedetomidine with butorphanol, as adjunct to midazolam and ketamine anaesthesia, on the clinicophysiological and haemodynamic stability in midazolam and ketamine anaesthesia. Atropine (0.04 mg kg) followed by dexmedetomidine (20μg kg) after 5 min IM were administered to each animal. Animals were randomised into groups D, DB of eight animals each. In group DB butorphanol (0.1mg kg ) IM was also administered at the time of dexmedetomidine administration. After 10 min of premedication, anaesthesia was induced with midazolam (0.8 mg kg) IV, in all the groups and maintained with 1% ketamine as and when required. Excellent jaw tone relaxation, abolished palpebral reflex with no significant (P>0.05) difference between two groups was observed. Heart rate showed an initial increase followed by a decrease, while respiratory rate decreased below the baseline in all the groups. RT decreased significantly (P<0.05) below the baseline. SBP, DBP and MAP increased initially in all the groups and then decreased until 120 min interval. However, mean arterial pressure remained above the baseline throughout the observation period in all the groups. Addition of butorphanol did not have significant effects on the clinico-physiological and haemodynamic stability; however, it reduced the amount of ketamine required for maintenance and better sedation.