Shoulder Dislocation Reduction Using Inhaled Nitrous Oxide in the Emergency Department: Retrospective Case Series

Introduction: Inhaled nitrous oxide (iNO) offers rapid onset analgesia with a favorable safety profile yet remains underused for shoulder dislocation reductions in the emergency department (ED). The objective of this study was to evaluate the use and outcomes of iNO for shoulder reduction in the ED, including whether intravenous (IV) access was required, whether successful reduction could be accomplished without additional analgesic or sedative medications under procedural sedation, and the rate of adverse effects from iNO. Methods: We conducted a retrospective chart review of shoulder dislocation reductions using iNO at two high-volume EDs over three years (2019–2022). Data collected included age, sex, indication, procedural success, IV placement, medications administered, and adverse events and was stored in a password-protected database. The primary endpoint was successful reduction with iNO as the primary procedural analgesic; secondary endpoint was occurrence of any adverse events. Results: Of 138 patients, 125 (90.6%; 95% CI, 0.84-0.95) achieved successful reduction with iNO alone without escalation to procedural sedation; 102 patients (74%) did not require IV access. Adverse events were rare (2/138 or 1.4% [95% CI, 0.02-0.05]): one patient experienced transient agitation (a known side effect of N-methyl-D-aspartate antagonism), and one had vomiting. Both were self-limited without hemodynamic changes. Conclusion: This retrospective case series, the largest of its kind to date examining iNO for shoulder dislocation reduction, demonstrated a 90.6% success rate with minimal adverse events and reduced resource utilization compared to procedural sedation. These findings support further prospective investigation of iNO for shoulder dislocation as well as other orthopedic reductions and painful ED procedures.