Evaluation of propofol as a general anesthetic for horses.

This research study investigates the use of propofol as a general anesthetic for horses. The results from the study highlight how the impact and effectiveness of the anesthetic vary based on the dosage that was administered.

Study Design

• The research was conducted employing a Latin square design, a method of experimental design that ensures every treatment is deployed evenly across all experimental units. This approach minimises the impact of systematic bias and other confounding variables.
• Three different levels of propofol dosage (2, 4, and 8 mg/kg) were administered intravenously to six mature horses on different occasions.
• The study tracked various metrics including anesthetic induction, duration, and recovery along with physiological markers such as heart rate, respiratory rate, pHa, PaCO2 and PaO2.
• The data was then analysed using a mixed model analysis of variance, a general linear model analysis, and least square means test for post hoc comparisons. Any results were deemed significant if P<.05.

Findings and Observations

• The quality of induction of anesthesia was inconsistent, ranging from poor to good. Notably, the lowest dose of propofol (2 mg/kg) did not result in recumbency in two horses.
• All doses of propofol occasionally caused unpredictable movements, such as brief paddling limb movements, after inducing recumbency.
• During recovery, horses exhibited calmness and coordination in their movements, suggesting a potentially smooth recovery process from the anesthetic.
• Recumbency duration (measured in minutes) increased with dose; 15.05 +/- 1.58 following 2 mg/kg, 31.06 +/- 5.56 following 4 mg/kg, and 47.85 +/- 13.63 following 8 mg/kg.
• Significant physiological changes were noted during the recumbency period for all dosages. These included an increase in heart rate, significant respiratory depression (only noticed after the administration of 8 mg/kg), and a decrease in PaO2 levels.

Summary

• The findings of this study suggest that the administration of propofol as a general anesthetic for horses presents variable results. These depend on the dose, and can impact heart rate, respiratory rate, and other physiological factors. The research process and results provide a valuable foundation for future investigations into propofol use in equine medicine. Detailed full-length studies would facilitate a better understanding of these findings and potential implications.