Facts and Figures on Regional Perfusion in the Horse

Regional limb perfusion with antimicrobials (ARLP) has become a common adjunct therapy for the treatment of orthopaedic infections in horses. This technique provides high antimicrobial concentrations in regional tissues including bones, joints and soft tissues without the need of high systemic antimicrobial concentrations.

ARLP can be performed either under general anaesthesia or standing sedation. Even though tourniquet efficacy has been demonstrated when used on the standing sedated horse, ARLP under general anaesthesia is frequently believed to produce higher regional antimicrobial concentrations because of the lack of movement of the horse, which could increase tourniquet efficacy. However, in a recent study synovial concentrations after ARLP did not differ significantly between horses under general anaesthesia or standing sedation.

When ARLP is performed on the standing horse, adequate sedation is necessary since tourniquet application is painful to the horse. Perineural anaesthesia performed at a location proximal to the tourniquet improves the comfort of the animal but addition of local anaesthetic to the perfusate does not.

Different tourniquets can be used successfully but narrow tourniquets such as rubber cables should be avoided. Human studies have shown that the tourniquet pressure required to maintain vascular isolation is inversely proportional to tourniquet width. It is generally recommended that a tourniquet width be of at least the diameter of the extremity on which to be placed. A wide elastic tourniquet as the Esmarch bandage is commonly used and was as effective as or better than the pneumatic tourniquet when placed proximal or distal to the equine carpus, respectively.  [...]