Comparison of two indirect techniques for local delivery of a high dose of an antimicrobial in the distal portion of forelimbs of horses.
OBJECTIVE
To compare isolated limb retrograde venous injection (ILRVI) and isolated limb infusion (ILI) for delivery of amikacin to the synovial fluid of the distal interphalangeal and metacarpophalangeal joints and to evaluate the efficacy of use of an Esmarch tourniquet in standing horses.


METHODS
6 healthy adult horses.


METHODS
Horses were randomly assigned in a crossover design. In ILRVI, the injection consisted of 1 g of amikacin diluted to a total volume of 60 mL administered during a 3-minute period. In ILI, the infusion consisted of 1 g of amikacin diluted to 40 mL administered during a 3-minute period followed by administration of boluses of diluent (82 mL total) to maintain vascular pressure. During ILI, the infusate and blood were circulated from the venous to the arterial circulation in 5-mL aliquots. Synovial fluid and serum samples were obtained to determine maximum amikacin concentrations and tourniquet leakage, respectively.


RESULTS
Both techniques yielded synovial concentrations of amikacin > 10 times the minimum inhibitory concentration (MIC) for 90% of isolates (80 microg/mL) and > 10 times the MIC breakpoint (160 microg/mL) of amikacin-susceptible bacteria reported to cause septic arthritis in horses. These values were attained for both joints for both techniques. Esmarch tourniquets prevented detectable loss of amikacin to the systemic circulation for both techniques.


CONCLUSIONS
Both techniques reliably achieved synovial fluid concentrations of amikacin consistent with concentration-dependent killing for bacteria commonly encountered in horses with septic arthritis. Esmarch tourniquets were effective for both delivery techniques in standing horses.
Errico
Jason A
JA
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
Trumble
Troy N
TN
Bueno
Aloisio C D
AC
Davis
Jennifer L
JL
Brown
Murray P
MP
D000583:Amikacin / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics; D000818:Animals; D000890:Anti-Infective Agents / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics; D018592:Cross-Over Studies; D005260:Female; D005552:Forelimb / Q000378:metabolism; D006736:Horses / Q000097:blood / Q000378:metabolism*; D017148:Infusions, Intraosseous / Q000662:veterinary*; D007275:Injections, Intravenous / Q000662:veterinary*; D010477:Perfusion / Q000662:veterinary; D013582:Synovial Fluid / Q000378:metabolism*; D014111:Tourniquets / Q000662:veterinary
D000890:Anti-Infective Agents; D000583:Amikacin