Ultrasound-guided supraclavicular block

By: _____Arthur Atchabahian, MD_____ Assistant Professor of Anesthesiology Director of Regional and Orthopedic Anesthesia, St Vincent Catholic Medical Center

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Video 1: Left subclavian artery and nerves of the brachial plexus.
The subclavian artery is seen beating at the center of the field. Underlying it is the first rib, with a bright cortical bone and a posterior shadow. The pleura are seen on each side of the rib, somewhat deeper, and moving with the patient’s respiration. The nerves of the brachial plexus can be seen lateral and a little superficial to the artery. The distribution is variable, with as little as two or as many as 10 nerves seen.

Video 2: Right supraclavicular block anatomy. Similar to video 1, but on the right side. Again, the subclavian artery is seen beating, with the plexus lateral and superficial to it. The first rib, with its posterior shadow, underlies the artery.

Video 3: Left supraclavicular block anatomy using color Doppler.
Same position as Video 1. The color Doppler is turned on, showing flow in the subclavian artery. In cases when the anatomy is somewhat distorted, the color Doppler can be useful to identify vascular structures. Remember that the flow is toward and away from the probe, so that if the probe is perpendicular to the blood flow, no signal will be seen. One has to incline the probe to obtain an adequate flow signal.

Video 4: Penetration of the needle in the “sheath”and injection. The needle is seen being advanced toward the plexus. When it penetrates the “sheath”, a “pop” can often be perceived. After aspiration, a small amount of local anesthetic is injected, confirming the location of the needle is the correct plane. Occasionally, the “popping” will bring the needle tip beyond the plexus sheath, and the needle will have to be slightly withdrawn

Video 5: Supraclavicular block: Injection. (US supraclavicular.avi)
The needle is seen with its tip lying in the midst of the brachial plexus nerves. Local anesthetic is injected following aspiration, and the whole area of the plexus is seen bulging. Typically, the local anesthetic will diffuse away, and the nerves will be seen again after a few seconds. Nerves that do not seem to be adequately “bathed” by the local anesthetic injection can be targeted specifically, and more local anesthetic can be given.

Video 6: Supraclavicular block: Injection in the wrong plane.
In this case, while the needle appears to have entered the sheath, test injection rapidly demonstrates that the spread of local anesthetic happens in the wrong plane. The needle was subsequently advanced, and repeat injection was seen among the brachial plexus nerves.

Video 7: Supraclavicular block: Tracking the subclavian artery.
On occasion, if difficulty is encountered locating the subclavian artery and the brachial plexus, the carotid artery can be located in the neck, and then tracked down by sliding the probe until the bifurcation is seen. The subclavian artery can then followed in most patients laterally until it is seen in the supraclavicular fossa.

Video 8: Supraclavicular block: Tracking the nerves of the brachial plexus. As an alternative, the roots can be located in the interscalene area, and then tracked down by sliding the probe until they are seen in the subclavian area. Only the upper roots (C5 through C7) are typically seen in the interscalene area, and it is not uncommon to see the lower portion of the plexus, from C8 and T1, merging with it as one nears the supraclavicular area.