Comparison of intraosseous or intravenous infusion for delivery of amikacin sulfate to the tibiotarsal joint of horses.

Objective-To establish the route of infusion (IV or intraosseous) that results in the highest concentration of amikacin in the synovial fluid of the tibiotarsal joint and determine the duration of peak concentrations. Animals-21 horses. Procedure-Regional perfusion of a limb on 15 horses was performed. Amikacin sulfate was infused into the saphenous vein or via intraosseous infusion into the distal portion of the tibia (1 g in 56 ml of lactated Ringer's solution) or proximal portion of the metatarsus (1 g of amikacin in 26 ml of lactated Ringer's solution). Amikacin concentrations were, measured in sequential samples from tibiotarsal joint synovial fluid and serum. Samples were obtained immediately prior to release of the tourniquet and 0.5, 1, 4, 8,12, and 24 hours after the tourniquet was released. Radiographic contrast material was infused into the same locations as the antibiotic perfusate to evaluate distribution in 6 other horses. Results-Infusion into the saphenous vein produced the highest concentration of amikacin in the tibiotarsal joint; compared with the distal portion of the tibia (mean +/- SE, 701.8 +/- 366.8 vs 203.8 +/- 64.5 mug/ml, respectively). Use of a lower volume of diluent in the proximal portion of the metatarsus produced a peak value of 72.2 +/- 23.4 mug/ml. Conclusions and Clinical Relevance-For regional perfusion of the tarsus, IV infusion is preferred to intraosseous infusion, because higher concentrations are achieved in the synovial fluid, and the procedure is easier to perform.