The quality of induction of
general anesthesia produced by
ketamine and
propofol, 2 of the most commonly used anaesthetic agents in cats, was assessed. Eighteen cats admitted for elective procedures were randomly assigned to 3 groups and then premedicated with
xylazine 0.75 mg/kg intramuscularly before anaesthesia was induced with
ketamine 15 mg/kg intramuscularly (KetIM group),
ketamine 10 mg/kg intravenously (KetIV group) or
propofol 4 mg/kg intravenously (PropIV group). Quality of induction of general anaesthesia was determined by scoring ease of intubation, degree of struggling, and vocalisation during the induction period. The quality of induction of anaesthesia of intramuscularly administered
ketamine was inferior to that of intravenously administered
ketamine, while intravenously administered
propofol showed little difference in quality of induction from
ketamine administered by both the intramuscular and intravenous routes. There were no significant differences between groups in the ease of intubation scores, while vocalisation and struggling were more common in cats that received
ketamine intramuscularly than in those that received intravenously administered
ketamine or
propofol for induction of anaesthesia.
Laryngospasms occurred in 2 cats that received
propofol. The heart rates and respiratory rates decreased after
xylazine premedication and either remained the same or decreased further after induction for all 3 groups, but remained within normal acceptable limits. This study indicates that the 3 regimens are associated with acceptable induction characteristics, but administration of
ketamine intravenously is superior to its administration intramuscularly and laryngeal desensitisation is recommended to avoid
laryngospasms.