Effects of ketamine, propofol, or thiopental administration on intraocular pressure and qualities of induction of and recovery from anesthesia in horses.

The research article is a study on the impacts of different anesthetics, namely ketamine, propofol, and thiopental, on the intraocular pressure (IOP) in horses. It also evaluates the quality of induction of and recovery from anesthesia.

Methodology

• The study was conducted on six healthy adult horses in a crossover design, ensuring that each horse was exposed to all three anesthetics with a minimum interval of one week between treatments.
• Prior to the anesthesia, the horses were sedated using xylazine hydrochloride. Anesthesia was then induced with guaifenesin followed by ketamine, propofol, or thiopental.
• The IOP of each horse was measured in the right eye before and after administration of xylazine, at the point of recumbency, and at intervals of three minutes after the induction of anesthesia until the horse exhibited spontaneous movement.
• Cardiorespiratory responses and venous blood measurements were also recorded during the anesthesia process.
• The induction of and recovery from anesthesia were subjectively evaluated by researchers who did not know the type of anesthetic treatment each horse had received.

Results

• The study found that compared to xylazine administration, thiopental decreased the IOP by 4 ± 23%. However, propofol and ketamine increased the IOP by 8 ± 11% and 37 ± 16% respectively.
• At the time of recumbency, compared to the effects of ketamine, both propofol and thiopental resulted in significantly lower IOP and higher heart rates three minutes after the induction of anesthesia.
• No other significant differences were discovered among the treatments.

Conclusions

• The findings from this research suggest that in scenarios where it’s beneficial to minimize increases in IOP, thiopental or propofol should be used in preference to ketamine when anesthetizing horses.