A prospective comparison of procedural sedation and ultrasound-guided interscalene nerve block for shoulder reduction in the emergency department

Acad Emerg Med. 2011 Sep;18(9):922-7. doi: 10.1111/j.1553-2712.2011.01140.x. Epub 2011 Aug 30.


Objectives: Emergency physicians (EPs) are beginning to use ultrasound (US) guidance to perform regional nerve blocks. The primary objective of this study was to compare length of stay (LOS) in patients randomized to US-guided interscalene block or procedural sedation to facilitate reduction of shoulder dislocation in the emergency department (ED). The secondary objectives were to compare one-on-one health care provider time, pain experienced by the patient during reduction, and patient satisfaction between the two groups.

Methods: This was a prospective, randomized study of patients presenting to the ED with shoulder dislocation. The study was conducted at an academic Level I trauma center ED with an annual census of approximately 80,000. Patients were eligible for the study if they were at least 18 years of age and required reduction of a shoulder dislocation. A convenience sample of patients was randomized to either traditional procedural sedation or US-guided interscalene nerve block. Procedural sedation was performed with etomidate as the sole agent. Interscalene blocks were performed by hospital-credentialed EPs using sterile technique and a SonoSite MicroMaxx US machine with a high-frequency linear array transducer. Categorical variables were evaluated using Fisher's exact test, and continuous variables were analyzed using the Wilcoxon rank sum test.

Results: Forty-two patients were enrolled, with 21 patients randomized to each group. The groups were not significantly different with respect to sex or age. The mean (±SD) LOS in the ED was significantly higher in the procedural sedation group (177.3 ± 37.9 min) than in the US-guided interscalene block group (100.3 ± 28.2 minutes; p < 0.0001). The mean (±SD) one-on-one health care provider time was 47.1 (±9.8) minutes for the sedation group and 5 (±0.7) minutes for the US-guided interscalene block group (p < 0.0001). There was no statistically significant difference between the two groups in patient satisfaction or pain experienced during the procedure. There were no significant differences between groups with respect to complications such as hypoxia or hypotension (p = 0.49).

Conclusions: In this study, patients undergoing shoulder dislocation reduction using US-guided interscalene block spent less time in the ED and required less one-on-one health care provider time compared to those receiving procedural sedation. There was no difference in pain level or satisfaction when compared to procedural sedation patients.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Anesthetics, Local / administration & dosage
  • Conscious Sedation*
  • Emergency Service, Hospital
  • Etomidate / administration & dosage
  • Female
  • Humans
  • Hypnotics and Sedatives / administration & dosage
  • Length of Stay / statistics & numerical data
  • Lidocaine / administration & dosage
  • Male
  • Middle Aged
  • Nerve Block / methods*
  • Pain Measurement
  • Patient Satisfaction
  • Prospective Studies
  • Shoulder Dislocation / diagnostic imaging
  • Shoulder Dislocation / therapy*
  • Treatment Outcome
  • Ultrasonography, Doppler, Color
  • Ultrasonography, Interventional*


  • Anesthetics, Local
  • Hypnotics and Sedatives
  • Lidocaine
  • Etomidate