Page 59 - Manual of Equine Field Surgery

CHAPTER 8

Distal Limb Perfusion

Joanne Kramer

INDICATIONS ANATOMY

Infection of bone and soft tissues in the distal limb Regional perfusion delivers antibiotic into the

(Figure 8-1). venous system by intraosseous or intravenous

infusion. With pressure, the perfusate distends

the venous vasculature, allowing the perfusate

to enter tissue with intact venous vasculature.

EQUIPMENT Antibiotics then enter ischemic tissue and exu-

dates via increased hydrostatic presst1re in cap-

A cannulated screw with an appropriately sized illaries and diffusion across a concentration

drill bit and tap or commercially available gradient.1•2 During regional perfusion, the timing

intraosseous infusion needles are needed for of antibiotic delivery to the tissues is expected to

intraosseous perfusion (Figure 8-2). A 20- to follow a similar pattern to that observed follow-

26-gauge 1-inch catheter is necessary for intra- ing contrast medium. Shortly after intravenous

venous perfusion. For both techniques, an injection, contrast is in both the venous and arter-

Esmarch bandage or pneumatic tourniquet and ial systems; 15 minutes after injection, contrast

the selected antibiotic diluted in 60 mL of normal has started to diffuse into adjacent soft tissues;

saline are necessary. and 30 minutes after injection, contrast is pri-

marily in the adjacent soft tissues3 (Figure 8-3).

POSITIONING AND PREPARATION PROCEDURE

The limb should be clipped and prepared for Selected Antibiotics

aseptic surgery. Care should be taken to isolate

open, infected sites from the perfusion entry site. Antibiotics must be approved for intravenous

Depending on the nature of the horse, the proce- administration. Concentration-dependent antibi-

dure can be performed with the horse standing or otics such as gentamicin and amikacin are com-

under general anesthesia. For intraosseous perfu- monly used, but other antibiotics may be used as

sion, the initial procedure is often performed well. Ideally, antibiotic choice is guided by culture

under general anesthesia and follow-up proce- and sensitivity results. Because such high tissue

dures are performed standing. Standing proce- concentrations can be achieved locally with small

dures require sedation and regional anesthesia doses of antibiotic, antibiotics that are cost-

above the area to be perfused. prohibitive to use systemically can be used. In

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