Training Level and Analgesic Outcomes of Ultrasound-Guided Nerve Blocks in the Emergency Department

Ultrasound-guided nerve blocks (UGNBs) are increasingly used in the emergency department (ED) for analgesia and to facilitate procedures, yet the impact of operator training level and prior block experience on block efficacy and safety is not well defined. We evaluated whether Emergency Medicine (EM) attending physicians and residents achieve different analgesic outcomes when performing UGNBs in the ED setting and whether prior block experience was associated with analgesic efficacy.

This is a secondary analysis of the National Ultrasound-Guided Nerve (NURVE) Block Registry, involving 11 U.S. EDs from January 1, 2022, to December 31, 2023. Adult patients undergoing UGNBs for acute pain or procedural analgesia were included, totaling 1,595 procedures after exclusion of incomplete post-procedural pain scores. The primary outcome was percent pain reduction, with >50% defined as clinically meaningful and >75% as substantial analgesia. Outcomes were compared by operator training level, prior block experience, and block type; block-related complications were recorded.

Among 1,595 eligible procedures, 424 (26.6%) were performed by attendings and 1,171 (73.4%) by residents. Attendings achieved clinically meaningful pain reduction in 80.7% of cases versus 63.4% for residents, and substantial reduction in 68.1% versus 47.7%, respectively (p<0.01). This difference persisted in the highest experience tier (>20 prior blocks: 82.3% vs 71.0%, p<0.01). Across resident experience tiers, efficacy remained stable (65.3%–71.2% with clinically meaningful pain reduction). Complications were rare (0.13%, p<0.01), all transient and occurring in resident-performed blocks.

Ultrasound-guided nerve blocks in the ED performed by attendings were associated with greater analgesic success than those performed by residents, yet both groups achieved high rates of clinically meaningful pain reduction with very low complication rates. Stable resident efficacy across experience tiers and the low complication rate support the safety of supervised resident training and underscore the importance of experience and structured supervision in ED-based regional analgesia.