Desflurane and sevoflurane elimination kinetics and recovery quality in horses.

This study researched the effects of two anesthetic gases, desflurane and sevoflurane, on the recovery time and quality of recovery in horses. It was found that while both anesthetic gases were effective and safe, desflurane was eliminated more quickly from the horse’s body, resulting in faster recovery times.

Methodology

• The study involved six healthy adult horses that were anesthetized with either sevoflurane or desflurane gas. The concentration used was 1.2 times the minimum alveolar concentration, maintained for a two-hour period.
• Horses were allowed to recover without assistance. During this recovery period, end-tidal gas samples were collected until the horses spontaneously moved.
• The concentrations of the anesthetics were determined using gas chromatography. After a one-week washout period, the anesthetic gases were swapped, and the procedure was repeated.
• The recovery period was recorded on video and the quality of recovery was rated using a visual analog scale by investigators unaware of the anesthetic administered.

Results

• All horses recovered from the anesthesia without major injuries and subjective evaluations of recovery did not differ between the two anesthetics.
• The desflurane anesthetic was found to have a smaller area under the elimination curve and a significantly shorter time to standing recovery, suggesting faster clearance from the body.
• However, the distribution and elimination constants showed no significant difference between the two anesthetics.

Conclusion

• Overall, the study confirms that the desflurane anesthetic is eliminated more rapidly than sevoflurane in horses, as predicted by previous knowledge about anesthetic blood solubility differences in this species.
• This more rapid elimination was associated with faster recovery times for the horses, although it did not improve the subjective quality of recovery.