Objective: To compare anaesthetic induction and recovery characteristics of diazepam-ketamine combination to propofol alone in dogs undergoing elective orchidectomy.
Experimental design: Prospective, randomised clinical trial.
Animal population: Thirty six healthy adult male dogs of various breeds weighing 5.5 ± 2.3kg and aged 26 ± 13 months. Materials and Methods: After demeanour scoring (simple descriptive scale; (SDS); the dogs were sedated with morphine (0.3mg/kg) and acepromazine (0.02mg/kg) intramuscularly. Forty minutes after administration, a premedication score (SDS) was allocated. Immediately after premedication had been scored, general anaesthesia was induced with either a combination of diazepam and ketamine (D/K) or propofol (P) intravenously to facilitate endotracheal intubation. Anaesthesia was maintained with isoflurane. Scores for the quality of induction, intubation and degree of myoclonus were allocated (SDS). Orchidectomy was performed in a standard way by a single experienced surgeon. Recovery from anaesthesia was scored (SDS). Times to extubation and standing were recorded. Data were analysed for statistically significant differences using the t-test for parametric data and the Wilcoxon Mann-Whitney test for non-parametric data. The Kappa Reliability and Kendall Tau tests were used to assess the degree of agreement between the scorers for the scored characteristics.
Results: There were no statistically significant differences between groups in age, weight, cage rest score, premedication score and duration of maintenance of anaesthesia. Group P was associated with a poorer quality of induction and more pronounced myoclonus; but had better quality of recovery and shorter recovery times compared to group D/K.
Conclusions: Diazepam-ketamine and propofol are associated with acceptable induction and recovery from anaesthesia. Propofol had inferior anaesthetic induction characteristics, but better and quicker recovery from anaesthesia compared to diazepam-ketamine in male dogs premedicated with morphine and acepromazine.