Comparison of two tourniquet application times for regional intravenous limb perfusions with amikacin in sedated or anesthetized horses.

The research study compares the effects of two different tourniquet application periods (20 minutes versus 30 minutes) on the concentration of a drug, amikacin, in horses’ joints. It also looks at whether the horse’s state (anesthetized or sedated) influences the effectiveness of drug concentration. The study found no significant difference caused by the two different tourniquet times on drug concentrations, but it did find sedated horses had higher concentrations of the drug in certain joint areas compared to anesthetized horses.

Study Details

• The study involved performing Regional Limb Perfusion (RLP), a treatment technique for infections in the limbs of horses, in two groups of six horses each. The two groups were distinguished based on whether the horse was given General Anesthesia (GA) or Standing Sedation (SS).
• A pneumatic tourniquet was applied to the horse’s limb for either 20 or 30 minutes. The procedure was repeated two weeks later, with the opposite tourniquet time used, and on the opposite limb.
• Synovial fluid, the lubricating substance in the joints, was taken from two types of joints – the metacarpophalangeal (MCP) and radiocarpal (RC).
• The concentration of amikacin, an antibiotic commonly used to treat bacterial infections, in the collected synovial fluid was measured using a fluorescence polarization immunoassay, a technique used to quantify the presence of specific substances.

Key Findings

• The results showed that the application times of the tourniquet did not significantly affect the concentration of amikacin in the synovial fluid. This suggests that both the 20-minute and the 30-minute tourniquet times were equally effective.
• However, the state of the horse did have an effect on drug concentration. Sedated horses displayed significantly higher concentrations of amikacin in their MCP joints after 30 minutes compared to those under general anesthesia. The concentrations in their RC joints were not significantly different.

Implications and Conclusions

• The findings suggest that the tourniquet application time may not be a major concern when performing an RLP procedure with amikacin in horses, as either 20 minutes or 30 minutes yields the same concentration of the drug.
• But the overall state of the horse, whether sedated or anaesthetized, might influence the drug’s effectiveness. Given that drug concentration was higher in sedated horses’ joints, sedation may be the more ideal state for RLP with amikacin treatment.
• These findings contribute to the broader understanding of RLP treatment efficacy and drug concentration, providing useful and practical insights for veterinarians and horse caretakers.