Effect of perfusate volume on amikacin concentrations after saphenous intravenous regional limb perfusion in standing, sedated horses.
Authors: Jurek Kelsey A, Schoonover Mike J, Williams Megan R, Rudra Pratyaydipta
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: Perfusate Volume and Amikacin Delivery via Saphenous IVRLP in Standing Horses Intravenous regional limb perfusion (IVRLP) via the saphenous vein is a useful technique for delivering antibiotics directly to distal hind limb joints in standing horses, but optimal perfusate volumes remain unclear. Kelsey and colleagues performed a randomised crossover study in six adult horses, administering 1 g amikacin diluted to either 10 ml, 60 ml, or 120 ml volumes via saphenous IVRLP, then sampling synovial fluid from three distal hind limb joints (tarsocrural, metatarsophalangeal, and distal interphalangeal) at 15 and 30 minutes post-perfusion. Whilst perfusate volume had no statistically significant effect on synovial amikacin concentrations across joints, all three joints achieved therapeutic concentrations (>40 µg/ml for susceptible organisms) at 30 minutes when using 60 ml or 120 ml volumes; notably, the 10 ml volume only achieved therapeutic levels in the distal interphalangeal joint. Despite these findings, no treatment group reached the higher therapeutic threshold (160 µg/ml) needed for resistant pathogens. These results support use of 60 ml or 120 ml perfusate volumes for susceptible bacterial infections in distal hind limb joints, though clinicians treating potentially resistant infections should consider whether higher amikacin doses might be necessary to achieve adequate synovial concentrations through this route.
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Practical Takeaways
- •Use 60-120 ml perfusate volumes for saphenous IVRLP to reliably treat susceptible bacterial infections in distal hind limb joints
- •Allow at least 30 minutes post-perfusion before sampling or expecting peak therapeutic drug concentrations in synovial fluid
- •Higher amikacin doses or alternative antibiotics should be considered for suspected resistant pathogens, as standard dosing does not achieve adequate concentrations
Key Findings
- •Perfusate volume (10 ml, 60 ml, or 120 ml) did not significantly affect synovial fluid amikacin concentrations across joints (P = 0.4)
- •Synovial amikacin concentrations were significantly higher at 30 minutes compared to 15 minutes post-perfusion (P = 0.003)
- •60 ml and 120 ml volumes achieved therapeutic concentrations (>40 μg/ml) for susceptible pathogens in all distal hind limb joints, but failed to reach target levels (160 μg/ml) for resistant pathogens