Supraclavicular Block

Published on 06/02/2015 by admin

Filed under Anesthesiology

Last modified 06/02/2015

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5 Supraclavicular Block

David L. Brown, with contributions from Brian D. Sites, Brian C. Spence

Perspective

Supraclavicular block provides anesthesia of the entire upper extremity in the most consistent, efficient manner of any brachial plexus technique. It is the most effective block for all portions of the upper extremity and is carried out at the division level of the brachial plexus; perhaps this is why there is often little or no sparing of peripheral nerves if an adequate paresthesia is obtained. If this block is to be used for shoulder surgery, it should be supplemented with a superficial cervical plexus block to anesthetize the skin overlying the shoulder.

Patient Selection

Almost all patients are candidates for this block, with the exception of those who are uncooperative. In addition, in less experienced hands it may be inappropriate for outpatients. Although pneumothorax is an infrequent complication of the block, such an event often becomes apparent only after a delay of several hours, when an outpatient may already be at home. Also, because the supraclavicular block relies principally on bony and muscular landmarks, very obese patients are not good candidates because they often have supraclavicular fat pads that interfere with easy application of this technique.

Pharmacologic Choice

As with other brachial plexus blocks, the prime consideration in drug selection should be the length of the procedure and the degree of motor blockade desired. Mepivacaine (1% to 1.5%), lidocaine (1% to 1.5%), bupivacaine (0.5%), and ropivacaine (0.5 to 0.75%) are all applicable to brachial plexus block. Lidocaine and mepivacaine will 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 less involved or outpatient surgical procedures. For extensive surgical procedures requiring hospital admission, a longer-acting agent like bupivacaine can be chosen. Plain bupivacaine produces surgical anesthesia lasting from 4 to 6 hours, and the addition of epinephrine may prolong this time to 8 to 12 hours, whereas ropivacaine is slightly shorter acting.

Traditional Block Technique

The anatomy of interest for this block is the relationship between the brachial plexus and the first rib, the subclavian artery, and the cupola of the lung (Fig. 5-1). My experience suggests that this block is more difficult to teach than many of the other regional blocks, and for that reason two approaches to the supraclavicular block are illustrated: the classic Kulenkampff approach and the vertical (“plumb bob”) approach. The vertical approach has been developed in an attempt to overcome the difficulty and time necessary to become skilled in the classic supraclavicular block approach. Both techniques are clinically useful, once mastered. As the subclavian artery and brachial plexus pass over the first rib, they do so between the insertion of the anterior and middle scalene muscles onto the first rib (Fig. 5-2). The nerves lie in a cephaloposterior relationship to the artery; thus, a paresthesia may be elicited before the needle contacts the first rib. At the point where the artery and plexus cross the first rib, the rib is broad and flat, sloping caudad as it moves from posterior to anterior, and although the rib is a curved structure, there is a distance of 1 to 2 cm on which a needle can be “walked” in a parasagittal anteroposterior direction. Remember that immediately medial to the first rib is the cupola of the lung; when the needle angle is too medial, pneumothorax may result.