Anesthesia of horses with a combination of detomidine, zolazepam, tiletamine, and isoflurane immediately after strenuous treadmill exercise.

The research aimed to investigate the effects of heavy exercise on horses before anaesthesia and its impact on both the induction and recovery periods of anaesthesia. The researchers found that utilising a combination of detomidine, zolazepam, tiletamine, and isoflurane for sedation and anaesthesia of horses post-strenuous exercise was safe and efficient, showing potential for application in athletic events to facilitate quick treatment during injuries.

Methods of the Research

• The study involved six healthy, adult Thoroughbred horses that were in good physical condition and were trained to run on a treadmill regularly, with each horse serving as its own control.
• Initially, the horses were subjected to strenuous treadmill exercise until they showed signs of fatigue.
• Immediately following the exercise, the horses were sedated with detomidine hydrochloride, further anesthetized with a combination of zolazepam hydrochloride-tiletamine, and then maintained on isoflurane in oxygen for about 90 minutes.
• Blood samples were obtained from the horses at various stages: before exercise, during exercise, after exercise, and during anesthesia, to evaluate multiple physiological parameters.

Significant Findings

• Notable changes were observed during the exercise, including increases in heart rate, core body temperature, plasma lactate concentration, arterial pH, and partial pressure of carbon dioxide (PaCO2).
• The plasma concentration of ionized calcium was lower after exercise as compared to baseline, and it remained lower at 30 minutes of isoflurane anesthesia.
• The plasma chloride concentration remarkably decreased during anesthesia after exercise compared to baseline.
• The cardiac output of the horses during anesthesia was notably lower than it was during pre-exercise, though no significant differences were observed between the experimental and control periods.
• The arterial blood pressure during anesthesia was significantly lower than during pre-exercise, but it was initially better maintained during isoflurane anesthesia post-exercise.

Conclusions Drawn From the Research

• The researchers concluded that the administration of detomidine hydrochloride followed by zolazepam hydrochloride-tiletamine seems safe and effective for sedation and anesthesia of horses following strenuous exercise. Even though cardiac output and blood pressure were reduced during anesthesia, they remained within a clinically acceptable range.
• The study suggests that the anesthetic protocol used can be safely adopted to anesthetize horses that have been injured during athletic competitions in order to assess injuries, facilitate first aid, and possibly increase the chances of saving injured horses.