Time required to achieve maximum concentration of amikacin in synovial fluid of the distal interphalangeal joint after intravenous regional limb perfusion in horses.

This research was conducted to ascertain the time required to reach the maximum concentration of amikacin in the distal interphalangeal (DIP) joint of horses following intravenous regional limb perfusion (IVRLP). The results indicated that the maximum concentration (Cmax) of amikacin was achieved 15 minutes post-IVRLP, suggesting that a tourniquet application of 15 minutes should suffice when targeting an adequate concentration of the antibiotic in the synovial fluid of the DIP joint.

Study Approach and Procedure

• The research involved nine adult horses as subjects. They were sedated and secured in a standing posture, after which IVRLP was administered using the cephalic vein. The procedure involved the use of 2 grams of amikacin sulfate diluted with a saline solution and perfused using a peristaltic pump over three minutes.
• A pneumatic tourniquet was placed around the horse’s limb, 10 cm above the accessory carpal bone, to facilitate the insertion of amikacin into the bloodstream.
• The synovial fluid samples from the DIP joint and blood samples from the jugular vein were extracted at different intervals after IVRLP. These were then evaluated through a fluorescence polarization immunoassay to quantify the amikacin levels academically.

Findings of the Study

• Two horses had to be excluded from the study due to non-collection of an adequate volume of synovial fluid, leaving seven participants effectively.
• An analysis of the resultant data revealed that the median Cmax of amikacin in the DIP joint was 600 μg/mL, ranging from 37 to 2,420 μg/mL.
• Moreover, the median time to reach this maximum concentration, also referred to as Tmax, was approximately 15 minutes post-IVRLP.

Conclusion and Clinical Implication

• The research concluded that the Tmax of amikacin in the DIP joint of horses was 15 minutes after IVRLP, and Cmax did not increase after this period, regardless of the tourniquet’s continued application.
• This study’s findings suggest that a tourniquet applied for 15 minutes should be sufficient for successful IVRLP in horses to achieve an appropriate amikacin concentration in the synovial fluid of the DIP joint. This information is valuable in a clinical setting to administer this procedure more optimally.