Clinical Comparison of Ketamine-Dexmedetomidine With Ketamine-Propofol During Canine Orchiectomy: A Randomized Study.

Objective: To compare the effects of two different protocols, ketamine with dexmedetomidine (ketamine-dexmedetomidine [KD]) and ketamine with propofol (ketamine-propofol [KP]), on intubation time, selected cardiopulmonary parameters, and anaesthesia maintenance during canine orchiectomy in a clinical setting.

Study design: Randomized clinical trial.

Animals: Twenty-six healthy dogs were undergoing orchiectomy.

Methods: Dogs were randomly assigned to the KD group [n = 13; single intravenous bolus of ketamine (5 mg kg^-1) combined with dexmedetomidine (10 µg kg^-1)], or KP group [n = 13, an intravenous bolus of ketamine combined with propofol at a 1:2 concentration ratio and infused at a 0.2 mL kg^-1 min^-1 rate for 120 s until jaw relaxation and the consumed amount recorded]. Orotracheal intubation followed the induction of anaesthesia. The cardiopulmonary variables were assessed at baseline and 5-min intervals up to 30 min. A 20% increase in at least two variables, such as heart rate (HR), mean arterial pressure (MAP) and respiratory rate, prompted the administration of top-ups. Following surgery, the recovery time and quality were assessed.

Results: There was no significant difference in intubation time between KD (3.3 ± 0.8) and KP (2.7 ± 0.9, p = 0.121). Over time, HR and MAP significantly increased in the KP group compared to the KD group (p < 0.001). The haemoglobin oxygen saturation was higher in the KD group (97.7% ± 2.1%) compared to the KP (95.3% ± 2.2%, p = 0.015). The duration of the top-up requirement was longer in the KD group as compared to a single bolus of KP, with a mean difference of 31.2 min (95% CI 20.80-41.51) (p < 0.01).

Conclusions and clinical relevance: Both KP and KD combinations effectively maintain anaesthesia during canine castration surgery, demonstrating comparable intubation times. Although KP requires additional top-ups, it potentially offers enhanced cardiovascular stability compared to KD. However, the use of KP necessitates support of body temperature and oxygenation.