Increasing tourniquet number has no effect on amikacin concentration within the radiocarpal joint in horses undergoing intravenous regional limb perfusion

OBJECTIVE To determine whether IV regional limb perfusion (IVRLP) performed in the cephalic vein with a wide rubber tourniquet (WRT) applied proximal and distal to the carpus results in a higher peak concentration (C-max) of amikacin in the radiocarpal joint (RCJ), compared with the C-max for IVRLP using a single WRT proximal to the carpus. ANIMALS 7 healthy adult horses. PROCEDURES Horses underwent IVRLP using standing sedation with 2 g of amikacin sulfate diluted to 60 mL by use of saline (0.9% NaCl) solution in the cephalic vein with 2 different tourniquet techniques; proximal WRT (P) and proximal and distal WRT (PD). Synovial fluid was collected from the RCJ at 5, 10, 15, 20, 25, and 30 minutes after IVRLP. Tourniquets were removed after the 30-minute sample was collected. Blood samples from the jugular vein were collected at 5, 10, 15, 20, 25, 29, and 31 minutes after IVRLP. Am ikacin concentration was quantified by a fluorescence polarization immunoassay. Median peak concentration (C-max)of amikacin and time to maximum drug concentration (T-max) within the RCJ were determined. RESULTS Median peak concentration in the RCJ was 1331.4 mu g/mL with technique P and 683.1 mu g/mL with technique PD. Median T-max occurred at 30 minutes with technique P and 25 minutes with technique PD. No significant P = 0.18; L ax , P = 0.6) difference in amikacin C-max or T-max between techniques was detected.