A Comparison Between Ultrasound-Guided Infraclavicular Block Using the “Double Bubble” Sign and Neurostimulation-Guided Axillary Block

In Brief BACKGROUND: Ultrasound-guided infraclavicular block can be performed using the double bubble sign. Previously described, the double bubble sign consists superiorly of the axillary artery (in short axis) superimposed on an inferior bubble created by local anesthetic injection. In this study, we compared this new method of brachial plexus anesthesia to the traditional triple-nerve stimulation axillary block. METHODS: Seventy patients were randomized to receive a single-injection, ultrasound-guided infraclavicular block using the double bubble sign or a triple-stimulation axillary block. RESULTS: Both methods produced similar success rates (89%–91%). However, infraclavicular blocks were associated with a shorter performance time (3.90 ± 2.27 vs 8.03 ± 3.92 min; P < 0.001) and lower block-related pain scores (2.70 ± 2.02 vs 4.17 ± 2.57 on a 0–10 scale; P = 0.01). CONCLUSION: Compared to triple-stimulation axillary block, ultrasound-guided infraclavicular block using the double bubble sign provided a similar efficacy, a shorter performance time and lower procedural pain scores. IMPLICATIONS: Compared to triple-stimulation axillary block, single-injection ultrasound-guided infraclavicular block using the “double bubble” sign (consisting of the axillary artery viewed in short axis superimposed on an inferior bubble created by local anesthetic injection) yielded a similar success rate. However, ultrasound-guided infraclavicular block was associated with a decrease in performance time and block-related pain.