Comparison of propofol with ketofol, a propofol-ketamine admixture, for induction of anaesthesia in healthy dogs.

Objective: To compare anaesthetic induction in healthy dogs using propofol or ketofol (a propofol-ketamine mixture).

Study Design: Prospective, randomized, controlled, 'blinded' study.

Animals: Seventy healthy dogs (33 males and 37 females), aged 6-157 months and weighing 4-48 kg.

Methods: Following premedication, either propofol (10 mg mL(-1)) or ketofol (9 mg propofol and 9 mg ketamine mL(-1)) was titrated intravenously until laryngoscopy and tracheal intubation were possible. Pulse rate (PR), respiratory rate (f(R)) and arterial blood pressure (ABP) were compared to post-premedication values and time to first breath (TTFB) recorded. Sedation quality, tracheal intubation and anaesthetic induction were scored by an observer who was unaware of treatment group. Mann-Whitney or t-tests were performed and significance set at p ≤ 0.05.

Results: Induction mixture volume (mean ± SD) was lower for ketofol (0.2 ± 0.1 mL kg(-1)) than propofol (0.4 ± 0.1 mL kg(-1)) (p < 0.001). PR increased following ketofol (by 35 ± 20 beats minute(-1)) but not consistently following propofol (4 ± 16 beats minute(-1)) (p < 0.001). Ketofol administration was associated with a higher mean arterial blood pressure (MAP) (82 ± 10 mmHg) than propofol (77 ± 11) (p = 0.05). TTFB was similar, but ketofol use resulted in a greater decrease in f(R) (median (range): ketofol -32 (-158 to 0) propofol -24 (-187 to 2) breaths minute(-1)) (p < 0.001). Sedation was similar between groups. Tracheal intubation and induction qualities were better with ketofol than propofol (p = 0.04 and 0.02 respectively).

Conclusion And Clinical Relevance: Induction of anaesthesia with ketofol resulted in higher PR and MAP than when propofol was used, but lower f(R). Quality of induction and tracheal intubation were consistently good with ketofol, but more variable when using propofol.