A single pneumatic tourniquet is superior to wide rubber tourniquets for saphenous intravenous regional limb perfusion with amikacin in standing, sedated horses.

Overview

• This study compared different types and numbers of tourniquets used during intravenous regional limb perfusion (IVRLP) of amikacin in standing, sedated horses to determine the most effective method for delivering the antibiotic to joint spaces.
• It found that a single pneumatic tourniquet placed mid-gaskin is superior to wide rubber tourniquets and multiple tourniquets in optimizing amikacin concentrations in joint fluid while minimizing systemic leakage.

Background

• Intravenous regional limb perfusion (IVRLP) is a technique used to administer antibiotics locally to limbs, enhancing drug concentrations in joints to treat infections while reducing systemic side effects.
• Tourniquets are applied to isolate the limb segment, preventing drug dispersion into systemic circulation and ensuring high local drug concentration.
• Different tourniquet types, such as pneumatic and wide rubber, and the number of tourniquets used, could influence drug delivery efficiency and systemic leakage.

Objectives

• To compare the effect of tourniquet type (pneumatic vs wide rubber) and tourniquet number (single vs dual) on amikacin concentrations in synovial fluid from two important equine joints: the tarsocrural joint (TCJ) and the metatarsophalangeal joint (MTPJ).
• To assess serum concentrations of amikacin as a measure of systemic leakage resulting from different tourniquet protocols.

Methods

• Subjects: 8 healthy adult horses.
• Study design: Randomized crossover design where each horse underwent four different IVRLP protocols varying by:
• Tourniquet type: pneumatic vs wide rubber
• Tourniquet number: single (one placed mid-gaskin) vs dual (one mid-gaskin and one mid-metatarsus)
• Amikacin dosage: 2 g administered via saphenous IVRLP while the horse was standing and sedated.
• Measurements: Amikacin concentrations were measured in serum and synovial fluid from the TCJ and MTPJ at 15 and 30 minutes post-administration.
• Statistical analysis: Linear mixed-effects model to compare amikacin concentration differences between protocols and joints.

Results

• Synovial fluid amikacin concentrations:
• No significant differences were found between the single-tourniquet protocols (pneumatic vs wide rubber) in either joint.
• Dual pneumatic tourniquet protocol led to significantly higher synovial fluid amikacin concentrations compared to the dual wide rubber protocol.
• There was no difference in amikacin concentrations between single and dual pneumatic protocols.
• In the TCJ, the single wide rubber protocol resulted in higher amikacin concentrations compared to the dual wide rubber protocol; no significant differences were seen in the MTPJ.
• Serum amikacin concentrations:
• Lower serum concentrations (less systemic leakage) were observed with pneumatic tourniquets compared to wide rubber tourniquets.

Conclusions

• Using a single tourniquet produces equal or higher joint concentrations of amikacin than using two tourniquets, making multiple tourniquet use unnecessary.
• Pneumatic tourniquets are more effective than wide rubber ones in limiting systemic leakage of the antibiotic.
• Given these findings, a single mid-gaskin pneumatic tourniquet is recommended for saphenous IVRLP in standing, sedated horses to maximize local efficacy and minimize systemic exposure.

Implications for Clinical Practice

• Veterinarians performing IVRLP in horses should prefer a single pneumatic tourniquet for better antibiotic delivery and safety.
• This method may reduce the cost, complexity, and risk associated with using multiple or wide rubber tourniquets.
• Improved local antibiotic concentrations can enhance treatment success of joint infections in equine patients.