Anesthetic and cardiorespiratory effects of propofol, medetomidine, lidocaine and butorphanol total intravenous anesthesia in horses.

This research investigates the effects of a specific category of anesthetic drugs used on horses during surgery, focusing on their cardiorespiratory impact. It concludes that the drugs can provide effective surgical anesthesia with minimal side effects, although use of propofol, in particular, needs further investigation for its potential to enhance the transition to anesthesia.

Study Design and Procedure

• The research team evaluated the anesthetic and cardiorespiratory effects of four drugs – propofol, medetomidine, lidocaine, and butorphanol – when used in total intravenous anesthesia (TIVA) in horses undergoing experimental surgery. The four-drug mix is referred to as MLBP-TIVA.
• Ten horses were premedicated with medetomidine and butorphanol via intravenous injection, then put under anesthesia using propofol, which was given at two different concentrations to create two study groups of five horses each.
• Following propofol administration, lidocaine was administered. Anesthesia was then maintained by continuous infusions of all four drugs.

Anesthesia Duration and Quality

• The mean duration of anesthesia and minimum required propofol infusion rate for maintaining surgical anesthesia were just over two hours. These measurements did not significantly vary across the two study groups.
• The quality of anesthesia induction and recovery were both deemed satisfactory, with median quality scores of three and four on a scale of zero to four and zero to five, respectively.

Transition to Anesthesia and Cardiorespiratory Effects

• The transition to anesthesia went more smoothly in the group given a higher concentration of propofol (Group 2), compared to the group that received the lower concentration (Group 1).
• Group 2 also had a significantly higher quality score for the transition to anesthesia compared to Group 1.
• Heart rate and arterial blood pressure were maintained within acceptable levels in both groups, though both experienced hypercapnia (excessive carbon dioxide in the bloodstream) during anesthesia.

Conclusions

• The study concluded that MLBP-TIVA can provide effective surgical anesthesia in horses.
• However, the authors noted that rapid induction with propofol at a higher concentration might further improve the quality of anesthesia induction and the transition to sedation.