Intravenous Regional Limb Perfusion in Standing and Recumbent Horses: A Comparative Radiographic Study

Area of Science:

• Veterinary Medicine
• Equine Surgery
• Pharmacology

Background:

• Intravenous regional limb perfusion (IRLP) is used for equine orthopedic infections.
• Optimal drug distribution via IRLP may depend on patient positioning.
• Current understanding of positional effects on IRLP in horses is limited.

Purpose of the Study:

• To compare the perfusion of radiopaque contrast in equine limbs during IRLP when horses are in standing versus recumbent positions.
• To determine if horse positioning affects the speed and uniformity of drug distribution in the extremities.

Main Methods:

• 10 healthy horses underwent IRLP with radiopaque contrast in both standing (sedated) and recumbent (anesthetized) positions, with a two-week washout period.
• Radiographic images were taken sequentially for 50 minutes post-administration.
• Time to contrast arrival at the hooves and distribution patterns were analyzed.

Main Results:

• Contrast reached the hooves significantly faster in standing horses (114 ± 15 s) compared to recumbent horses (236 ± 29 s).
• Standing position resulted in more uniform limb vessel perfusion and greater soft tissue diffusion.
• Recumbent position led to contrast pooling in specific veins and reduced distal distribution.

Conclusions:

• Performing intravenous regional limb perfusion in standing horses leads to quicker and more uniform vascular perfusion and tissue diffusion compared to recumbent horses.
• Horse positioning significantly impacts drug distribution during IRLP.
• Standing position is recommended for optimizing IRLP efficacy in horses.