Time to Peak Concentration of Amikacin in the Antebrachiocarpal Joint Following Cephalic Intravenous Regional Limb Perfusion in Standing Horses.

This study aimed to determine how long it takes for the antibiotic, amikacin sulphate, to reach maximum concentration in a joint in a horse’s leg after injecting the antibiotic into the horse’s foreleg vein and restricting the blood flow using a tourniquet.

Methodology

• For this study, a medical procedure known as cephalic intravenous regional limb perfusion (IVRLP) was carried out on six healthy adult mixed breed mares.
• 2 grams of amikacin sulphate, an antibiotic, was diluted in a saline solution (0.9% NaCl) to a total volume of 100 milliliters.
• This solution was infused into a vein in the foreleg of the horse using a 23-gauge butterfly catheter.
• To confine the antibiotic to the limb, an Esmarch’s rubber tourniquet was applied for 30 minutes.
• Synovial fluid was collected from the radiocarpal joint, which is in the lower foreleg, prior to infusion and at 5, 10, 15, 20, 25, and 30 minutes following the IVRLP.
• The tourniquet was released after the last fluid collection. The concentration of amikacin sulphate in the synovial fluid was determined by liquid chromatography/tandem mass spectrometry, a highly sensitive and accurate tool used for the measurement of organic molecules.

Results

• In general, the peak concentration was reached approximately 15 minutes post IVRLP. The timing was a bit different between individual horses: the peak concentration was noted at 10 minutes in 2 horses, 15 minutes in 2 horses, and 20 minutes in 2 horses.
• The highest mean (average) concentration, 1023 µg/mL, was noted at 20 minutes.
• There was a statistically significant difference in the concentrations between 15 and 30 minutes after IVRLP was performed, indicating that the concentration was not uniform during this period.

Conclusions

• Based on the results, the researchers concluded that a tourniquet application time of 30 minutes seemed to be unnecessary, as the maximum antibiotic concentration was reached by 20 minutes.
• In light of these findings, they suggest that the most appropriate tourniquet application duration for the treatment of the radiocarpal joint in cephalic IVRLP using 2 grams of amikacin sulphate should be 20 minutes.