Comparison of two tourniquets and determination of amikacin sulfate concentrations after metacarpophalangeal joint lavage performed simultaneously with intravenous regional limb perfusion in horses

Abstract

On standing horses, IVRLP performed simultaneously with joint lavage resulted in negligible loss of amikacin in the egress lavage fluids. The Esmarch tourniquet was more effective in preventing loss of amikacin from the distal portion of the limb, easier to use, and less expensive than the pneumatic tourniquet.

Effects of regional limb perfusion volume on concentrations of amikacin sulfate in synovial and interstitial fluid samples from anesthetized horses

“…The lack of horse movement was likely important to maintaining tourniquet integrity. 1,3,16 An anesthetized horse positioned in lateral recumbency could be reasonably expected to have a lower blood pressure throughout the distal portion of the limb than would a standing horse because its systemic blood pressure would be lower and because partial exsanguination of the limb might occur prior to tourniquet placement. 9 Baseline venous blood pressures (85 to 125 mm Hg) identified in standing horses in a study 19 involving various IVRLP procedures were 3 to 4 times the baseline venous blood pressures (20 to 50 mm Hg) identified in anesthetized horses in the present study.…”

“…Patient movement can result in leakage of perfusate under the tourniquet, leading to a decrease in the amount of antimicrobial available for diffusion into extravascular spaces. 1,3,16,17 In the other study, 15 serum samples were not obtained to determine whether the administered antimicrobial had entered systemic circulation. Because of the possible effects of leakage under the tourniquet, it is difficult to interpret the results of that study.…”

“…Use of this tourniquet results in less leakage of perfusate into systemic circulation during regional limb perfusion performed in standing horses. 1 However, application and tourniquet pressure of the Esmarch tourniquet cannot be standardized. To reduce variability in tourniquet pressure among limbs in the present study, a pneumatic tourniquet with a 10-cm cuff set to a cuff pressure of 400 mm Hg was used.…”

“…However, injection of large volumes for IVRLP can lead to complications such as tourniquet failure and perfusate (antimicrobial plus diluent) leakage into systemic circulation. 1,2,4,9,10 In addition, injection of a large versus small volume for IVRLP in standing horses results in more severe signs of pain, resulting in horse movement and tourniquet displacement. 4 Both pressure and concentration likely play a role in antimicrobial distribution during IVRLP.…”

“…[1][2][3][4][5][6] These concentrations reportedly exceed 50 times the MICs of antimicrobials against common equine bacterial pathogens. 3,5,6 The MIC of amikacin against most equine bacterial pathogens is 16 µg/mL.…”