Effects of using a propofol priming and coinduction with ketamine or S(+) Ketamine on the dose of induction and duration of propofol in cats.

The study aimed to evaluate the effects of racemic ketamine and S (+) ketamine coinduction with propofol, comparing these to propofol alone and propofol as its own coinductor, on anesthetic induction, cardiorespiratory parameters, intubation conditions, and recovery in cats. Thirty-two healthy cats were divided into four groups (n = 8): GC (propofol at 1 mg/kg/min, titrated to effect, administered via a syringe infusion pump), GP (propofol priming of 1 mg/kg and 0.5 ml of NaCl 0.9% bolus as placebo, followed by propofol to effect at 1 mg/kg/min), GKet (propofol priming of 1 mg/kg and a racemic ketamine bolus of 2 mg/kg, followed by propofol to effect at 1 mg/kg/min), and GKet+ (propofol priming of 1 mg/kg and a S (+) ketamine bolus of 2 mg/kg, followed by propofol to effect at 1 mg/kg/min). Cats were premedicated with gabapentin (150 mg/cat) one hour before procedures to minimize stress. Propofol infusion began 30 seconds after coinduction and was titrated until loss of jaw tone and laryngotracheal reflex. Heart rate, respiratory rate, temperature, and systolic blood pressure were recorded every 10 min until the return of the laryngotracheal reflex. Recovery times, intubation attempts, and adverse effects were recorded and analyzed. Baseline parameters were similar across groups, except for temperature (P = 0.003). Propofol doses were significantly lower in the GKet+ compared to GC (P = 0.004). Intubation attempts and reinduction doses did not differ between groups. Heart rate changes were significant between 0 and 20 min in the placebo and S (+) ketamine groups. Recovery exhibited a notable difference in ocular bulb centralization between GC and GKet+ (P = 0.008). Other parameters did not show differences. S (+) ketamine coinduction with propofol priming reduced propofol requirements in cats without increasing adverse effects and maintained stable cardiorespiratory parameters. Recovery profiles were comparable, with a slight delay in ocular bulb return to a central position in the S (+) ketamine group. These findings highlight the potential of S (+) ketamine and propofol priming as effective and safe strategies in veterinary anesthetic protocols.