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Brown: Atlas of Regional Anesthesia, 3rd ed., Copyright © 2006 Saunders, An Imprint of Elsevier
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Chapter 7 – Axillary Block

PERSPECTIVE

Axillary brachial plexus block is most effective for surgical procedures distal to the elbow. In some patients, procedures on the elbow or lower humerus can be carried out with an axillary technique, but strong consideration should be given to a supraclavicular block for those requiring more proximal procedures. It is discouraging to carry out a “successful” axillary block only to find that the surgical procedure extends outside the area of the block. This block is appropriate for hand and forearm surgery; thus, it is often the most appropriate technique for outpatients being treated in a busy hand surgery practice. There are anesthesiologists who find axillary block suitable for elbow surgical procedures, and continuous axillary catheter techniques may be indicated for postoperative analgesia in these patients. Because this block is carried out distant from both the neuraxial structures and the lung, complications associated with those areas are avoided.

Patient Selection.

For performance of an axillary block, patients must be able to abduct the arm at the shoulder. As the experience of the operator increases, the need for this diminishes, but the block cannot be carried out with the arm at the side. Because the block is most appropriate for forearm and hand surgery, it is a rare patient with a surgical condition at those sites who cannot abduct the arm as described.

Pharmacologic Choice.

Hand and wrist procedures often require less motor blockade than procedures on the shoulder; therefore the concentration of local anesthetic chosen can usually be slightly decreased with an axillary block compared with that needed for a supraclavicular or interscalene block. Appropriate drugs are lidocaine (1%–1.5%), mepivacaine (1%–1.5%), bupivacaine (0.5%), and ropivacaine (0.5%–0.75%). Lidocaine and mepivacaine produce 2 to 3 hours of surgical anesthesia without epinephrine and 3 to 5 hours when epinephrine is added. These drugs can be useful for uncomplicated procedures or outpatient surgical procedures. For more extensive surgical procedures requiring hospital admission, a longer-acting agent such as bupivacaine may be chosen. Plain bupivacaine and ropivacaine produce surgical anesthesia that lasts 4 to 6 hours; the addition of epinephrine may prolong this period to 8 to 12 hours. The local anesthetic time line must be considered when prescribing a drug for outpatient axillary block, as blocks lasting as long as 18 to 24 hours can result from higher concentrations of bupivacaine with added epinephrine. With the continuous catheter techniques used for postoperative analgesia or chronic pain syndromes, 0.25% bupivacaine or 0.2% ropivacaine may be used, and even lower concentrations of these drugs may be used after a trial.

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