Clinical and pharmacokinetic effects of regional or general anaesthesia on intravenous regional limb perfusion with amikacin in horses.

This research study evaluates the clinical and pharmacokinetic effects of regional or general anaesthesia on the administration of amikacin through intravenous regional limb perfusion (IV-RLP) in horses. The study found that perineural regional anaesthesia was most effective in providing comfort to sedated horses without significantly affecting the regional distribution and absorption of the medicine.

Research Methodology

• The research was conducted as an experimental crossover study on eight healthy horses.
• The horses were subjected to four different treatments of amikacin IV-RLP, namely standing sedation without regional anaesthesia, standing sedation with intravenous regional anaesthesia, standing sedation with perineural regional anaesthesia, and general anaesthesia.
• The study was conducted in a randomised, blinded design, which means the horses were assigned random treatments and the researchers were unaware of the treatments given to the horses.
• The concentrations of the drug amikacin in the synovial fluid, which lubricates the joints of the horse, were measured over a 24-hour period.
• Pharmacokinetic parameters, which include the rate and extent of drug absorption in the body, were calculated based on these measurements.
• The researchers also assessed the horse’s comfort level, heart and respiratory rates, number of times the leg was lifted, and whether additional sedatives were required.

Study Findings

• No significant difference was found in the concentrations and regional pharmacokinetics of amikacin across the different treatments.
• The use of perineural regional anaesthesia resulted in significantly lower discomfort scores and less frequent limb lifting in sedated horses, compared to both intravenous regional anaesthesia and no anaesthesia.
• There was high variability in the concentrations of synovial amikacin in the horses.

Conclusions and Implications of the Study

• The study concludes that perineural regional anaesthesia is most effective for standing, sedated horses undergoing IV-RLP with amikacin, provided it does not significantly interfere with the drug’s regional pharmacokinetics.
• There is no justification for using general anaesthesia for this procedure based on the study’s findings, which could have significant implications for improving the comfort and management of horses during IV-RLP treatment.