A Comparison of a Single or Triple Injection Technique for Ultrasound-Guided Infraclavicular Block: A Prospective Randomized Controlled Study

BACKGROUND: Good success rates have been reported with ultrasound-guided infraclavicular block using one or multiple injections of local anesthetic. We hypothesized that a separate injection of local anesthetics on each cord enhances the onset of complete sensory block. We designed this prospective randomized study to compare the rate of complete sensory block using one or three injections of local anesthetic. METHODS: Patients scheduled for hand, wrist, or elbow surgery were included in this study. All blocks were performed under ultrasound guidance. In Group S (single injection), 30 mL of mepivacaine 1.5%, was injected posterior to the axillary artery. In Group T (triple injections), 10 mL of mepivacaine 1.5% was injected on the posterior, medial, and lateral aspects of the axillary artery. Sensory block was evaluated every 3 min up to 30 min. The primary end point was the rate of complete sensory block at 15 min. RESULTS: Forty-nine and 51 patients were randomized in Groups S and T, respectively. The rate of complete sensory block was comparable at 15 min (Group S: 84%, Group T: 78%, P = 0.61) and at each time interval up to 30 min. There was no statistically significant difference in the rate of complications between the two groups. CONCLUSIONS: The success rate and the onset of complete sensory block after ultrasound-guided infraclavicular block are not enhanced by a triple injection of local anesthetic compared with a single injection posterior to the axillary artery. (Anesth Analg 2009;109:668-72)