Recovery of horses from general anesthesia after induction with propofol and ketamine versus midazolam and ketamine

Abstract

OBJECTIVE To evaluate quality of recovery from general anesthesia in horses after induction with propofol and ketamine versus midazolam and ketamine. DESIGN Prospective randomized crossover study. ANIMALS 6 healthy adult horses. PROCEDURES Horses were premedicated with xylazine (1.0 mg/kg [0.45 mg/lb], IV), and general anesthesia was induced with midazolam (0.1 mg/kg [0.045 mg/lb], IV) or propofol (0.5 mg/kg [0.23 mg/lb], IV), followed by ketamine (3.0 mg/kg [1.36 mg/lb], IV). Horses were endotracheally intubated, and anesthesia was maintained with isoflurane. After 60 minutes, horses were given romifidine (0.02 mg/kg [0.009 mg/lb], IV) and allowed to recover unassisted. Times to first movement, sternal recumbency, and standing and the number of attempts to stand were recorded. Plasma concentrations of propofol or midazolam were measured following induction and immediately before recovery. Recovery quality was scored by 3 graders with a recovery rubric and a visual analog scale. RESULTS Number of attempts to stand was significantly lower when horses received propofol (median, 2; range, 1 to 3) than when they received midazolam (median, 7.5; range, 3 to 16). For both the recovery rubric and visual analog scale, recovery quality was significantly better when horses received propofol than when they received midazolam. Plasma drug concentration at recovery, as a percentage of the concentration at induction, was significantly lower when horses received propofol than when they received midazolam. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that for horses undergoing short (ie, 60 minutes) periods of general anesthesia, recovery quality may be better following induction with propofol and ketamine, compared with midazolam and ketamine.

Equine anaesthesia-associated mortality: where are we now?

“…A recent abstract reported poorer recoveries in six horses when midazolam was used in conjunction with ketamine for anaesthesia induction than when propofol was used in conjunction with ketamine, before 1 hour of isoflurane anaesthesia (Jarrett et al. ). Poorer recovery scores following midazolam–ketamine anaesthesia inductions were associated with a higher residual percentage of midazolam in the plasma at the start of recovery compared with propofol, but the dose of midazolam used (0.1 mg kg −1 ) was also higher than is commonly described.…”

The Effects of Different Combinations of Anesthetic Drug on Cardiopulmonary Functions and Recovery Behavior in Horses

“…Ketamine is commonly used for induction in horses, combination of an alpha agonist with ketamine provided a smooth induction with reliable sedation and recovery. However, the addition of muscle relaxant such as diazepam can be used to balance the side effects of muscle rigidity from ketamine ( Jarrett et al, 2018). Heart rate variability (HRV) has been suggested to measure as a noninvasive index for autonomic nervous control (Pagani et al, 1986;Kishi, 2012).…”

A retrospective comparison of induction with thiopental/guaifenesin and propofol/ketamine in Thoroughbred racehorses anesthetized with sevoflurane and medetomidine during arthroscopic surgery

“…Based on its unsatisfactory anesthetic induction [5,12,13], JRA racehorse clinics have avoided the clinical use of propofol for induction. However, recent studies reveal that combining propofol with ketamine offers the possibility of improving recovery [11,17,21]. Jarrett et al report that for horses undergoing general anesthesia, quality of recovery may be better following induction with propofol (0.5 mg/kg) and ketamine (3.0 mg/kg) compared to that with midazolam and ketamine [11].…”

“…However, recent studies reveal that combining propofol with ketamine offers the possibility of improving recovery [11,17,21]. Jarrett et al report that for horses undergoing general anesthesia, quality of recovery may be better following induction with propofol (0.5 mg/kg) and ketamine (3.0 mg/kg) compared to that with midazolam and ketamine [11]. Wagner et al commented that the quality of early recovery from anesthesia in horses may be improved by some combinations of propofol (0.5-1.5 mg/kg) with ketamine (0.5-1.5 mg/kg) [21].…”