A systematic review and meta-analysis of ultrasound versus electrical stimulation for peripheral nerve location and blockade

We systematically reviewed peripheral nerve blockade guided by ultrasound versus electrical stimulation. We included 26 comparisons in 23 randomised controlled trials of 2125 participants. Ultrasound reduced the rate of pain during the procedure, relative risk (95% CI) 0.60 (0.41-0.89), p = 0.01. Ultrasound with or without electrical stimulation reduced the rate of analgesic or anaesthetic rescue versus electrical stimulation alone, relative risk (95% CI) 0.40 (0.29-0.54) and 0.29 (0.16-0.52), respectively, p < 0.0001 for both. The rate of rescue was unaffected by the addition of electrical stimulation to ultrasound, relative risk (95% CI) 1.07 (0.54-2.10), p = 0.85. Ultrasound, with or without electrical stimulation, reduced the pooled rate of vascular puncture, relative risk (95% CI) 0.23 (0.15-0.37), p < 0.0001. There was no difference in the rate of postoperative neurological side-effects, relative risk (95% CI) 0.76 (0.53-1.09), p = 0.13.