High-concentration nitrous oxide for procedural sedation in children: adverse events and depth of sedation

Pediatrics. 2008 Mar;121(3):e528-32. doi: 10.1542/peds.2007-1044.


Objective: Nitrous oxide is an attractive agent for procedural sedation and analgesia in the emergency department; however, there are limited safety data for high-concentration continuous-flow nitrous oxide (50%-70%) and its use in young children. We set out to characterize the depth of sedation and incidence of adverse events associated with various concentrations of nitrous oxide used in a pediatric emergency department.

Methods: This was a prospective observational study of nitrous oxide use for procedural sedation and analgesia in a tertiary children's hospital emergency department. Nitrous oxide concentration, adverse events, and sedation depth were recorded. Adverse events were categorized as mild or serious. Sedation depth was recorded on a sedation scale from 0 to 6.

Results: A total of 762 patients who were aged 1 to 17 years received nitrous oxide during the 2-year study period. A total of 548 (72%) received nitrous oxide 70%, and 101 (13%) received nitrous oxide 50%. Moderate or deep sedation with scores of < or = 2 occurred in 3% of patients who had received nitrous oxide 70% and no patients who had received nitrous oxide 50%. Mean sedation scores were 4.4 at nitrous oxide 70% and 4.6 at nitrous oxide 50%. Sixty-three (8.3%) patients sustained 70 mild and self-resolving adverse events, most of which were vomiting (5.7%); 2 (0.2%) patients had serious adverse events. There was no significant difference in adverse events rates between nitrous oxide 70% (8.4%) and nitrous oxide 50% (9.9%). There was no significant difference in the percentage of deep sedation when children who were < or = 3 years of age (2.9%) were compared with older children (2.8%).

Conclusions: In this largest prospective emergency department series, high-concentration continuous-flow nitrous oxide (70%) was found to be a safe agent for procedural sedation and analgesia when embedded in a comprehensive sedation program. Nitrous oxide also seems safe in children aged 1 to 3 years.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Anesthesia / methods
  • Anesthesia Recovery Period
  • Anesthetics, Inhalation / administration & dosage*
  • Anesthetics, Inhalation / adverse effects
  • Child
  • Child, Preschool
  • Conscious Sedation / methods*
  • Dose-Response Relationship, Drug
  • Emergencies
  • Emergency Service, Hospital
  • Female
  • Humans
  • Infant
  • Male
  • Nitrous Oxide / administration & dosage*
  • Nitrous Oxide / adverse effects
  • Probability
  • Prospective Studies
  • Sensitivity and Specificity


  • Anesthetics, Inhalation
  • Nitrous Oxide