Goals

The use of appropriate anesthesia allows for assessment and management of a wound while reducing physical and emotional trauma often associated with the procedure.

Background

Pain experienced as a result of lacerations or other wounds to the skin is caused by activation of Type C fibers in the peripheral nerves. Because these fibers lack a myelin sheath, local anesthetics (LA) alter their function and thus reduce the pain experienced as a result of the wound itself or any resulting assessment and repair. While the exact mechanism is not clear, LA appears to alter the physiological mechanism of the cell’s sodium gate and thus the transmission of pain sensation to the spinal cord and the brain.

Indications for local anesthesia agent

• Exploration, debridement, and repair of wounds of the skin and underlying tissue (e.g. lacerations)
• Removal of embedded foreign bodies
• Incision and drainage of an abscess
• Elective biopsy and/or removal of skin lesions (e.g. nevi, skin tags, keratoses, etc.)

Techniques for Providing LA

1. Topical
2. Infiltration
3. Field block

1. Topical anesthesia is especially useful in the management of small wounds in children who do not tolerate local infiltration. Application of a gauze pad soaked in 2% Xylocaine will provide sufficient anesthesia for cleaning and ease local infiltration of anesthesia prior to suturing.

2. Local infiltration is the injection of the anesthetic directly into the line of incision of the wound itself. An incised or open accidental wound should not be injected when grossly contaminated as contaminated tissue or materials may produce sepsis when introduced or forced into surrounding clean tissues.

Directly infiltrating a wound is the least painful method for the patient. Use a 5 cc syringe with a 25-gauge needle. The technique should include aspiration followed by slow injection. Each time the needle is reinserted aspiration must be performed. Use only enough Xylocaine necessary to obtain the desired level of anesthesia.

3. Regional anesthesia by field block is achieved by injecting the anesthetic agent on all sides and deep to the wound site, while avoiding injection of the lesion itself. Both methods are described in the information that follows.

Contraindications

• Allergy to the LA or any agents in the carrier solution