Regional anesthesia or regional nerve blocks are defined as infiltration of a peripheral nerve with local anesthetic agents to attenuate motor output and sensory input. It provides anesthesia to allow problems to be treated efficiently and with minimal discomfort. Patients typically tolerate nerve blocks better than direct wound infiltration. Nerve blocks often require less local anesthetic solution than does infiltration of large wounds.
Regional anesthesia provides sensory blockade of a region without altering the normal anatomic features of the area to be repaired.1 It may be considered for use in the repair of extensive wounds, incision and drainage of abscesses, foreign body removal, wound exploration, burn care, fracture reduction, or pain control. Once familiar with the body’s sensory innervation, the Emergency Physician can easily employ regional anesthesia techniques within the Emergency Department.
Locating and anesthetizing a peripheral nerve is accomplished in one of four ways. First is to identify the general location of the nerve using anatomy and landmarks. Infiltrate local anesthetic solution at that site and allow it to diffuse over the area. The second is to locate a nerve by using the injecting needle to elicit paresthesias. Once paresthesias are elicited, withdraw the needle 1 to 2 mm and allow the paresthesias to resolve before injecting the local anesthetic solution. Third, a nerve stimulator can be used to accurately locate peripheral nerves with motor fiber components. Use of a nerve stimulator does not require cooperation on the part of the patient. However, due to its complexity, a physician skilled in its use is required. Nerve stimulators are rarely available in the Emergency Department. Finally, ultrasound can be used to identify the target nerve and to inject the local anesthetic solution.
The traditional method used by Anesthesiologists to perform regional anesthesia involves a combination of surface landmarks and nerve stimulation. Over the past 10 to 15 years, ultrasound (US) has gained a prominent role in guiding nerve blocks. It offers the advantages of visualizing the nerve and the needle, as well as directly visualizing the deposition of local anesthetic solution around the nerve. Several small initial studies have shown that Emergency Physicians can safely perform US-guided nerve blocks.2-5
It is common to encounter children complaining of pain in the Emergency Department. Regional anesthesia is frequently overlooked in children. Its use is increasing and serves as an excellent opportunity to minimize pain in the pediatric population.6 It can be administered safely and effectively in these patients. A child may require intravenous or intramuscular sedation in conjunction with nerve blockade in more complicated cases. The use of nitrous oxide with pediatric patients in the Emergency Department has been found to be successful when used for forearm fracture manipulation.7 It can also be used for other procedures. Refer to Chapter 158 regarding the use of nitrous oxide as a supplement to performing the regional nerve block. The ...