ABSTRACT
Infiltrative anesthesia may cause excessive bleeding due to vasodilation caused by sympathetic blockade to the small vessels. This can be reduced by using solutions containing epinephrine. The hair over the area to be desensitized is clipped and the skin is surgically prepared. The smallest size needle should be used. Local anesthetic is injected as the needle is directed along one side of the pyramid. The needle is then withdrawn to the subcutaneous tissue and redirected along an adjacent side of the pyramid. Again, anesthetic is injected. Next, the needle is withdrawn and reinserted through an area of desensitized skin from the previous injections. This technique minimizes the number of needle insertions into sensitive skin. When long term infiltrative analgesia is desired such as following ear canal ablation, amputation, or thoracotomy, an implantable catheter attached to a disposable elastomeric reservoir may be used. Preliminary studies in canine patients have shown this device to be effective.
