Seventy-one percent of patients undergoing ED procedural sedation and analgesia with N2O did not meet established fasting guidelines. In this series, there was no association between preprocedural fasting and emesis. There were no serious adverse events.

Study objective: Nitrous oxide (N 2 O) is an attractive agent for procedural analgesia and sedation of children in the emergency department (ED). Despite increasing use, efficacy data for painful procedures are limited. This study aimed to determine pain scores during ED procedural sedation with N 2 O in the ED setting. Methods: Prospective observational study of N 2 O use as a sole agent for procedural analgesia at a tertiary children's hospital ED. Pain scores were obtained from patients and parents using visual analogue or faces scales, as appropriate. Parent and staff satisfaction with sedation and analgesia were assessed. Results: 124 children aged 1-17 years (mean 8.1) underwent procedural analgesia with N 2 O for 131 procedures. Most procedures were orthopaedic (44%) or laceration repair (30%). In 51% of patients (95% CI 42% to 60 to 23%) pain scores remained unchanged and in 34% (95% CI 26% to 43%) pain scores increased. Overall, 34% (95% CI 26% to 43%) patients had intraprocedural scores of 50 mm or greater and 21% (95% CI 14% to 29%) had pain scores of 70 mm or greater. Some procedures such as fracture reduction had a larger proportion of patients with high pain scores or 50 mm or greater (45%) and 70 mm or greater (29%). Staff rated both sedation and analgesia as ''adequate'' in 92%. Parents contacted in follow-up were satisfied or very satisfied with procedures in 96% and sedations in 93%. Conclusion: Data indicate that parents and staff are generally satisfied with N 2 O for procedural use in the ED. The efficacy of N 2 O as a sole agent in very painful procedures is limited.