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

The study was a simple comparison between two different drug combinations used in inducing general anesthesia in horses, with the aim of determining which method provided a better quality of recovery. The combinations tested were propofol and ketamine versus midazolam and ketamine.

Study Design and Procedures

• The research involved six healthy adult horses and was structured as a prospective randomized crossover study.
• Each horse was premedicated with xylazine before being induced into general anesthesia with either propofol and ketamine or midazolam and ketamine.
• Firmly securing an airway, the horses were then endotracheally intubated and maintained on anesthesia using isoflurane.
• After a 60-minute period, each horse was administered romifidine and allowed to recover unassisted.
• Key recovery milestones such as time to first movement, reaching sternal recumbency, and standing, as well as the number of attempts made to stand, were closely monitored and recorded.
• Blood samples were collected right after induction of anesthesia and immediately before recovery to measure plasma concentration levels of either propofol or midazolam.

Results and Findings

• The results showed that horses who were induced with propofol and ketamine exhibited a significantly lower number of attempts to stand during recovery than those induced with midazolam and ketamine.
• The propofol and ketamine group had a distinct advantage in terms of recovery quality according to both the recovery rubric and visual analog scale assessments.
• In terms of plasma drug concentration during recovery, horses who were administered propofol and ketamine had significantly lower levels when compared to their initial plasma drug concentration at induction. Horses who were administered midazolam and ketamine did not display this significant reduction.

Conclusions

• The data suggested that for horses undergoing 60 minutes of general anesthesia, recovery quality was potentially enhanced when induction was carried out using propofol and ketamine, as opposed to midazolam and ketamine.

The findings are particularly relevant to veterinary anesthesia protocols, as they suggest potential improvements in post-anesthetic recovery for equine patients. However, as with all studies, these results would need to be validated in a larger cohort and in more diverse clinical settings.