**7.6 Regional anesthesia**

240 A Bird's-Eye View of Veterinary Medicine

Fig. 1. For caudal and epidural anesthesia in cattle the injection site used is between

In both sheep and goats, anterior epidural anesthesia, induced by injection at the lumbosacral junction is easily performed and provides excellent analgesia and muscle

Recumbency may occur but is not a problem in these small animals. As in cattle, there is a

Hind limb ataxia is a serious problem, so only caudal epidural techniques are used. These are useful for various obstetrical manipulations and surgery on the rectum, vagina and tail. The technique is less reliable than in cattle. Site of injection is usually sacrococcygeal junction but can be between C1 and C2. For a 500 kg horse, a mixture of 50 mg of xylazine and 6 ml of 2% mepivacaine (may be repeated for another dose) may prove very effective.

In this technique, a limb vein is catheterized. The limb is then exsanguinated (Esmarchs bandage), and a tourniquet placed around the limb, at a pressure adequate to prevent

Local anesthetic (preferably without epinephrine) is then injected into the vein. After a period of 15 minutes the area distal to the tourniquet is anesthetized until the tourniquet is

Potential problems are: a) Difficulty in finding the vein once the limb is exsanguinated (this is why it is best to have a catheter in place first). c) Cardiac arrhythmias or even arrest (this is due to an inadequate tourniquet). d) Failure to take effect. (common reasons are

coxygeal C1 and C2 (Modified from Thurmon *et al,* 1996)

**7.4.2 Epidural anesthesia in the sheep and goat** 

relaxation for abdominal surgery.

**7.4.3 Epidural anesthesia in the horse** 

**7.5 Intravenous regional local anesthesia** 

arterial circulation (> 150 mmHg).

removed.

risk of subarachnoid injection.

This term is used where specific nerves to the area concerned are blocked. Examples include specific nerve blocks to the limbs; paravertebral blocks; cornual block (for dehorning) and many others.
