Anesthesia of The Brachial Plexus - Techniques

Techniques

Brachial plexus block is typically performed by an anesthesiologist. To achieve an optimal block, the tip of the needle should be close to the nerves of the plexus during the injection of local anesthetic solution. Commonly employed techniques for obtaining such a needle position include transarterial, elicitation of a paresthesia, and use of a peripheral nerve stimulator or a portable ultrasound scanning device. If the needle is close to or contacts a nerve, the subject may experience a paresthesia (a sudden tingling sensation, often described as feeling like "pins and needles" or like an electric shock) in the arm, hand, or fingers. Injection close to the point of elicitation of such a paresthesia may result in a good block. A peripheral nerve stimulator connected to an appropriate needle allows emission of electrical current from the needle tip. When the needle tip is close to or contacts a motor nerve, characteristic contraction of the innervated muscle may be elicited. Modern portable ultrasound devices allow the user to visualize internal anatomy, including the nerves to be blocked, neighboring anatomic structures and the needle as it approaches the nerves. Observation of local anesthetic surrounding the nerves during ultrasound-guided injection is predictive of a successful block. Appropriate block per site-specific procedure are listed in the following table: