Comparison of intraocular pressure, tear production and cardiorespiratory variables before and after induction of anaesthesia with either propofol or ketofol in dogs premedicated with midazolam

Abstract

The objective of the present study was to compare the effects of propofol and ketofol on intraocular pressure, tear production and cardiorespiratory variables in dogs premedicated with midazolam. Six castrated adult mixed-breed dogs were used in a cross-over design with a one-week interval. Twenty minutes after premedication with midazolam (0.2 mg/kg), animals were assigned randomly to two groups and received either propofol (6 mg/kg) or ketofol (3 mg/kg; 1 : 1 mg/ml ratio) treatments intravenously. Intraocular pressure, tear production, heart rate, respiratory rate, rectal temperature and direct mean arterial blood pressure were measured at base (before induction), and at 5, 10, 15, 20 and 30 min after induction of anaesthesia. Blood gas samples were obtained at base (before induction), and at 5, 15 and 30 min after administration of treatments. Intraocular pressure showed significantly higher values at 5 min after induction in ketofol compared with propofol (16.1 ± 4.5 mm Hg vs 8.2 ± 1.2 mm Hg, respectively). There were no significant changes in tear production in either group. Significantly higher heart rate and mean arterial blood pressure were detected in ketofol at several time points. Respiratory depression occurred in both groups with no significant differences between them. In conclusion, although ketofol improved heart rate and mean arterial blood pressure and did not elicit more pronounced respiratory depression than propofol, it resulted in significantly higher values of intraocular pressure at 5 min after administration in dogs. Despite the small number of dogs in this study, our results indicate that ketofol should not be recommended for ophthalmic surgical procedures in dogs. Appropriate oxygenation should be provided when propofol is used for ophthalmic surgeries.

WITHDRAWN: Determination of Minimum Infusion Rate and Cardiorespiratory Effects of Total Intravenous Anesthesia of Ketofol With or Without Lidocaine, Fentanyl or Dexmedetomidine in Dogs

“…In a study performed on dogs, TIVA with ketofol resulted in higher heart rate (HR) and acceptable mean arterial pressure (MAP) compared to the administration of propofol alone; meanwhile, the respiratory depression was more pronounced in ketofol treatment than propofol [1]. Respiratory depression has also been observed in those dogs induced either with ketofol alone or in combination with diazepam or midazolam [10,11].…”

Effects of propofol alone or in combination with ketamine on intraocular pressure in unpremedicated dogs

“…[10][11][12] As such, the search for an ideal anesthesia protocol that minimizes its impact on IOP has become a subject of great significance. [13][14][15] While volatile agents, particularly sevoflurane and desflurane/nitrous oxide, are preferred for their minimal impact on IOP, it is possible for ophthalmic patients to receive injectable anesthesia with induction agents in clinical settings. 16 Propofol and ketamine are commonly utilized injectable agents for the induction of anesthesia in clinical settings, including for ophthalmic surgical procedures.…”

“…3,15,23 However, information regarding the impact of KP combinations on IOP during anesthesia without premedication in dogs is limited. Although a crossover study has investigated the effects of a 1:1 KP ratio on IOP for 30 min in dogs, the study utilized a premedication agent (midazolam), 13 and the effect of KP on IOP without premedication in dogs remains uncertain.…”

“…Given the potential adverse consequences of sudden increases in IOP on patients with ocular disorders, it is imperative to have knowledge of the effects of anesthetic drugs on IOP 10–12 . As such, the search for an ideal anesthesia protocol that minimizes its impact on IOP has become a subject of great significance 13–15 …”