Effects of combined midazolam and propofol in anesthesia induction and recovery of cats undergoing ovariohisterectomy

Abstract

The objective of this study was to determine the effects of propofol and midazolam on induction of anesthesia in cats undergoing ovariohysterectomy, measured in terms of the quality of tracheal intubation, anesthesia induction, cardiorespiratory effects, and recuperation period. Thirty healthy adult cats were pretreated with acepromazine and morphine. After 30 min, they were divided into three groups: PG (n = 10), in which induction was performed with only intravenous propofol at doses required for intubation; MPG (n = 8), in which animals received intravenous midazolam (0.3 mg kg-1) administered over 30 s, followed by administration of propofol as in PG; and PMG (n = 9), in which propofol was first administered at a rate of 4 mg kg-1 min-1, after which midazolam was administered (0.3 mg/kg), followed by re-administration of propofol. In order to perform a blinded study, the PG and PMG received a 0.9% NaCl solution volume similar to the midazolam dose before induction (0.06 mL/kg). Similar to the other groups, the PG and MPG received (0.06 mL kg-1) saline 30 s after administration of propofol. In order to mimic the administration of midazolam, the saline solution was administered for 30s. The PG received 11.0 ± 1.38 mg kg-1 propofol, a greater dose than that administered to the PMG (p < 0.001) and MPG (p < 0.01), which received 7.9 ± 1.92 and 9.1 ± 2.20 mg kg-1, respectively. There were no differences in the intubation scores between groups. Previous use of midazolam did not affect agitation or excitement in cats; both sequences of propofol-midazolam administration are feasible, but the propofol-midazolam sequence was superior due to the lower propofol dose.