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.
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 µg/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 µg/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. (Am J Vet Res 2002;63:374–380).