Four-injection brachial plexus block using peripheral nerve stimulator: a comparison between axillary and humeral...

We conducted this prospective, randomized study to compare the success rate, performance time, and onset time of surgical anesthesia of a four-injection brachial plexus block performed at the axillary (Group Axillary; n = 50) or at the humeral (Group Humeral; n = 50) level using a peripheral nerve stimulator. All patients received 40 mL of a mixture of equal parts of 0.5% bupivacaine and 2% lidocaine. Four patients in Group Axillary and two in Group Humeral were excluded from the study because all of the four nerves were not localized in the allotted time. The incidence of complete block (91% versus 89%), defined as block of all the sensory areas below the elbow, and the onset time of sensory block (15 +/- 6 min versus 16 +/- 7 min) were not different between the groups. The performance time was shorter in Group Humeral (7 +/- 2 min versus 8 +/- 2 min; P < 0.005). Block performance pain was lower in Group Axillary patients (16 +/- 9 min versus 23 +/- 12 min; P < 0.005). For four-injection brachial plexus block, we conclude that both the axillary and the humeral approaches provide a high success rate and a rapid onset of sensory anesthesia; the differences found between the groups could be considered clinically unimportant.

Two methods of brachial plexus block using a nerve-stimulator were compared in a prospective study. A four-injection technique was performed at the axillary or at the humeral level. Both approaches provided a fast onset and a high success rate. The differences found between the groups could be considered clinically unimportant.