Clinico-physiological and haemodynamic changes during midazolam-ketamine anaesthesia in dogs premedicated with dexmedetomidine with or without pentazocine

Anaesthetic trials were conducted in 16 mixed breed dogs undergoing ovariohysterectomy to observe the effects of dexmedetomidine or dexmedetomidine with pentazocine as preanaesthetics to midazolam-ketamine anaesthesia, on the clinico-physiological and haemodynamic stability. Atropine (0.04 mg/kg) followed 5 min later by dexmedetomidine (20 μg/kg) were administered i.m. to each animal. The animals were randomised into groups D and DP of eight animals each. In group DP, pentazocine (3 mg/kg, i.m.) was also administered along with dexmedetomidine. After 10 min of premedication, anaesthesia was induced with midazolam (0.8 mg/kg, i.v.) in both groups and maintained with 1% ketamine as and when required. Excellent jaw tone relaxation with abolition of palpebral reflex was observed in animals of both groups with no significant (P>0.05) difference between the groups. Heart rate showed an initial increase followed by a decrease, while respiratory rate decreased below the baseline in both 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. Addition of pentazocine to dexmedetomidine basal anaesthesia did not have significant effects on the clinico-physiological and haemodynamic stability.