Complication Rates After Ultrasonography-Guided Nerve Blocks Performed in the Emergency Department.

Importance: Ultrasonography-guided nerve blocks (UGNBs) have become a core component of multimodal analgesia for acute pain management in the emergency department (ED). Despite their growing use, national adoption of UGNBs has been slow due to a lack of procedural safety in the ED. Objective: To assess the complication rates and patient pain scores of UGNBs performed in the ED. Design, Setting, and Participants: This cohort study included data from the National Ultrasound-Guided Nerve Block Registry, a retrospective multicenter observational registry encompassing procedures performed in 11 EDs in the US from January 1, 2022, to December 31, 2023, of adult patients who underwent a UGNB. Exposure: UGNB encounters. Main Outcomes and Measures: The primary outcome of this study was complication rates associated with ED-performed UGNBs recorded in the National Ultrasound-Guided Nerve Block Registry from January 1, 2022, to December 31, 2023. The secondary outcome was patient pain scores of ED-based UGNBs. Data for all adult patients who underwent an ED-based UGNB at each site were recorded. The volume of UGNB at each site, as well as procedural outcomes (including complications), were recorded. Data were analyzed using descriptive statistics of all variables. Results: In total, 2735 UGNB encounters among adult patients (median age, 62 years [IQR, 41-77 years]; 51.6% male) across 11 EDs nationwide were analyzed. Fascia iliaca blocks were the most commonly performed UGNBs (975 of 2742 blocks [35.6%]). Complications occurred at a rate of 0.4% (10 of 2735 blocks). One episode of local anesthetic systemic toxicity requiring an intralipid was reported. Overall, 1320 of 1864 patients (70.8%) experienced 51% to 100% pain relief following UGNBs. Operator training level varied, although 1953 of 2733 procedures (71.5%) were performed by resident physicians. Conclusions and Relevance: The findings of this cohort study of 2735 UGNB encounters support the safety of UGNBs in ED settings and suggest an association with improvement in patient pain scores. Broader implementation of UGNBs in ED settings may have important implications as key elements of multimodal analgesia strategies to reduce opioid use and improve patient care.