Brachial plexus block with or without ultrasound guidance

Purpose of review Should ultrasound or nerve stimulation be used for brachial plexus blocks? We investigated last year's literature to help answer this question. Recent findings Many of the reports concluded that ultrasound guidance may provide a higher success rate for brachial plexus blocks than guidance by nerve stimulator. However, the studies were not large enough to conclude that ultrasound will reduce the risk of nerve injury, local anesthetic toxicity or pneumothorax. Ultrasound may reveal anatomical variations of importance for performing brachial plexus blocks. For postoperative analgesia, 5 ml of ropivacaine 0.5% has been sufficient for an ultrasound-guided interscalene block. For peroperative anesthesia, as much as 42 ml of a local anesthetic mixture was calculated to be appropriate for an ultrasound-guided supraclavicular method. For the future, we notice that three-dimensional and four-dimensional ultrasound technology may facilitate visualizing the needle, the nerves and the local anesthetic distribution. Impedance measurements may be helpful for nerve blocks not guided by ultrasound. Summary We think that the literature gives a sufficient basis to recommend the use of ultrasound for guidance of brachial plexus blocks. The potential for ultrasound to improve efficacy and reduce complications of brachial plexus blocks requires larger scaled studies.