Comparison of two tourniquet application times for regional intravenous limb perfusions with amikacin in sedated or anesthetized horses.
Authors: Aristizabal F A, Nieto J E, Guedes A G, Dechant J E, Yamout S, Morales B, Snyder J
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary Regional limb perfusion (RLP) with amikacin is an established therapeutic option for treating synovial and osseous infections in the equine distal limb, yet optimal tourniquet application times and the influence of anaesthetic technique on drug delivery remain incompletely characterised. Researchers compared synovial amikacin concentrations following 20 or 30-minute tourniquet application in twelve horses (six under general anaesthesia and six under standing sedation), with each horse receiving both treatments on opposite forelimbs two weeks apart; amikacin concentrations were measured from metacarpophalangeal and radiocarpal joint synovial fluid using fluorescence polarisation immunoassay. Extending tourniquet time from 20 to 30 minutes did not produce significantly higher synovial amikacin concentrations in either joint or anaesthetic group, though standing sedated horses demonstrated significantly higher mean amikacin concentrations in the metacarpophalangeal joint at the 30-minute timepoint compared to anaesthetised horses (P=0.003). These findings suggest that the additional ten minutes of tourniquet application offers no pharmacokinetic advantage for achieving therapeutic synovial drug concentrations, allowing practitioners to minimise tissue ischaemia time and associated complications; however, the superior drug delivery observed in conscious horses under standing sedation warrants further investigation, as it may reflect differences in limb perfusion dynamics or drug distribution between the two techniques.
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Practical Takeaways
- •20 minutes of tourniquet time appears adequate for amikacin RLP in equine distal limbs—you do not need to extend to 30 minutes for better synovial penetration
- •Standing sedation may provide slightly higher drug concentrations in the MCP joint compared to general anesthesia, which could influence technique choice for superficial distal limb infections
- •RLP remains an effective treatment option for synovial and musculoskeletal infections in equine distal limbs regardless of whether horses are sedated or anesthetized
Key Findings
- •No significant difference in synovial amikacin concentrations between 20 and 30 min tourniquet application times regardless of anesthesia type
- •Standing sedated horses achieved significantly higher mean synovial amikacin concentrations in the MCP joint at 30 min (P=0.003) compared to general anesthesia
- •No significant difference in radiocarpal joint concentrations between general anesthesia and standing sedation groups
- •Regional limb perfusion with 1g amikacin achieved therapeutic synovial concentrations in distal equine limb joints