Feasibility and Adoption of Low-Volume Ultrasound-Guided Superior Trunk Block for Shoulder Reduction in the Emergency Department

Background: Procedural sedation and analgesia (PSA) is commonly used for shoulder dislocation reduction in emergency departments (EDs), but it requires monitoring resources and may be associated with sedation-related adverse events. Ultrasound-guided regional anesthesia (UGRA), particularly low-volume superior trunk (ST) block, has emerged as a potential alternative. However, little is known about how this technically demanding technique can be implemented and adopted in routine ED practice. This study aimed to describe the implementation and clinical adoption of low-volume ultrasound-guided ST block for shoulder reduction in a specialized ED over a six-year period. Methods: This retrospective single-center observational cohort study included all consecutive patients undergoing shoulder reduction in a specialized orthopedic ED between February 2018 and February 2024. Patients were managed according to routine clinical practice using either UGRA or PSA, with treatment choice determined by the treating physician. The primary objective was to describe the implementation and clinical adoption of low-volume ST block in routine practice. Additional analyses assessed temporal trends in technique utilization, local anesthetic volume, provider distribution, and ED length of stay. Results: A total of 206 patients were included (124 UGRA; 82 PSA). The use of UGRA increased progressively during the study period, whereas PSA decreased accordingly (p < 0.001). Most UGRA procedures were performed by a small group of experienced physicians, reflecting the gradual adoption of the technique in routine clinical practice. Local anesthetic volumes decreased significantly over time (p < 0.001), with most blocks ultimately performed using approximately 4–5 mL. Successful shoulder reduction was achieved in all patients. No conversion from UGRA to PSA was necessary. No clinically relevant complications such as respiratory or hemodynamic distress were observed in either group, although diaphragmatic function was not systematically assessed. Conclusions: This retrospective implementation analysis demonstrates that low-volume ultrasound-guided ST block was increasingly integrated into routine ED practice. The findings primarily describe the implementation and progressive adoption of a technically demanding regional anesthesia technique in a real-world setting. Prospective studies are warranted to further evaluate clinical effectiveness, patient-reported outcomes, and respiratory effects using standardized study protocols.