Evaluation of cardiovascular, respiratory and biochemical effects, and anesthetic induction and recovery behavior in horses anesthetized with a 5% micellar microemulsion propofol formulation.

This research study investigates the effects of a micellar microemulsion propofol formulation when used as a long-term anesthetic on horses; monitoring cardiovascular, respiratory, and biochemical impacts as well as evaluating the quality of anesthetic induction and recovery.

Research Methodology

• The study was a prospective experimental trial conducted on six healthy adult horses, aged around 9 years and weighed approximately 557 kg.
• Prior to anesthetic induction, all horses were administered xylazine intravenously for a period of 5 minutes.
• The anesthetic used was a 5% micellar microemulsion propofol formulation. This was first administered as a single bolus (phase I) and then as a 3-hour continuous infusion (phase II).
• The propofol pharmacokinetics observed during the phase I were used to set the initial infusion rates for the phase II.
• The horse’s anesthetic induction and recovery behavior was assessed qualitatively and quantitatively. Meanwhile, cardiovascular, respiratory, and biochemical measurements were taken through both anesthesia and recovery stages.

Research Findings

• The quality of induction varied significantly, ranging from good to poor.
• Regarding the recovery quality, the results were often excellent during phase I, but there were more variations among horses during phase II.
• Heart rates (HR) and mean arterial pressure (MAP) proved to be adequately maintained though there was significant hypoventilation developed during the procedure.
• Minimal changes were noticed in the blood biochemical analytes following anesthesia.

Conclusion and Recommendations

• The 5% micellar microemulsion propofol formulation produced similar results to those previously noted using commercially available propofol preparation when administered as a 3-hour continuous infusion.
• Based on the given results, the researchers suggest that the use of propofol as a primary anesthetic in horses for a prolonged period requires more study to determine its safety limits and clinical application.