Axillary Block

7 Axillary Block





Perspective


Axillary brachial plexus block is most effective for surgical procedures distal to the elbow. Some patients can undergo procedures on the elbow or lower humerus 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 block. This block is appropriate for hand and forearm surgery; thus, it is often the most appropriate technique for outpatients in a busy hand surgery practice. Some anesthesiologists 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.






Traditional Block Technique



Placement




Anatomy


At the level of the distal axilla, where the axillary block is undertaken (Fig. 7-1), the axillary artery can be visualized as the center of a four-quadrant neurovascular bundle. I conceptualize these nerves in quadrants like a clock face because multiple injections during axillary block result in more acceptable clinical anesthesia than does injection at a single site. The musculocutaneous nerve is found in the 9- to 12-o’clock quadrant in the substance of the coracobrachialis muscle. The median nerve is most often found in the 12- to 3-o’clock quadrant; the ulnar nerve is “inferior” to the median nerve in the 3- to 6-o’clock quadrant; and the radial nerve is located in the 6- to 9-o’clock quadrant. The block does not need to be performed in the axilla; in fact, needle insertion in the middle to lower portion of the axillary hair patch or even more distal to this is effective. It is clear from radiographic and anatomic study of the brachial plexus and the axilla that separate and distinct sheaths are associated with the plexus at this point. Keeping this concept in mind will help to decrease the number of unacceptable blocks performed. Also, this more distal approach to axillary block is similar to the mid-humeral brachial plexus block.



May 31, 2016 | Posted by in ANESTHESIA | Comments Off on Axillary Block

Full access? Get Clinical Tree

Get Clinical Tree app for offline access