Background and objectives: Educating residents in peripheral nerve blockade may impact the efficiency of a busy regional anesthesia service. Ultrasound guidance may affect the efficiency and effectiveness of nerve block. We examined the impact of ultrasound guidance on resident performance of peripheral nerve block in a regional anesthesia rotation.
Methods: An existing de-identified database was used for retrospective analysis of resident performance of interscalene, axillary, femoral, and popliteal nerve blocks, by peripheral nerve stimulator guidance alone and by nerve stimulator aided by ultrasound. The primary variable examined was the time required to perform the block. Others variables included (1) number of needle insertions; (2) proportion of blocks in which there was a blood vessel puncture; and (3) block efficacy. Peripheral nerve-stimulator blocks were guided by surface anatomy and motor stimulation, refined to 0.2 to 0.5 mA of current before injection of local anesthetic, while ultrasound nerve stimulator blocks were confirmed using a current of 0.5 mA.
Results: Ultrasound-aided blocks required less time to perform (median = 1.8 min) than nerve stimulator-guided blocks (median = 6.5 min, P < .001). More needle insertions were required for nerve localization in the nerve stimulator-guided blocks (median = 6) than in ultrasound-aided blocks (median = 2; P < .001). There were fewer blood vessel punctures with ultrasound-aided blocks (P = .03).
Conclusions: During resident teaching, ultrasound-aided peripheral nerve-stimulated block required less time to perform than did nerve-stimulator-guided blocks. Fewer needle insertions were required to perform the ultrasound-guided blocks, and there were fewer blood vessel punctures when ultrasound was used.