Intranasal fentanyl and high-concentration inhaled nitrous oxide for procedural sedation: a prospective observational pilot study of adverse events and depth of sedation

Acad Emerg Med. 2012 Jan;19(1):31-6. doi: 10.1111/j.1553-2712.2011.01241.x.


Objectives: Nitrous oxide (N(2)O) is an attractive agent for pediatric procedural sedation and analgesia (PSA) with rapid onset and offset of sedation. However, it has limited analgesic efficacy. Intranasal fentanyl (INF) provides nonparenteral analgesia. There are currently no data on the combined use of N(2)O and INF for PSA in children. The authors set out to prospectively assess the depth of sedation and incidence of adverse events when N(2)O and INF are used in combination in pediatric patients.

Methods: This was a prospective observational pilot study of combined N(2)O and INF for PSA at a tertiary children's hospital emergency department (ED). INF was administered at a precalculated dose of 1.5 μg/kg for preascertained weight ranges. N(2)O concentration, dose, timing of INF, adverse events, and sedation depth were recorded. Sedation depth was recorded using the University of Michigan Sedation Scale (UMSS).

Results: A total of 41 patients, aged 1 to 14 years, received INF within 2 hours prior to N(2)O. N(2)O was administered at a maximal concentration of 70% in 40 patients, and at 50% in one patient. Most patients (80%) were minimally to moderately sedated (sedation score 1 or 2). Deep sedation (sedation score 3) was recorded in 14.6% of patients (95% confidence interval [CI] = 3.4% to 24.6%). No patients had serious adverse events; vomiting was recorded in 19.5% (95% CI = 7.4% to 31.6%). There were two patients (4.9%) who were deeply sedated and vomited during the procedure.

Conclusions: There were no serious adverse events identified in this pilot study of combined N(2)O and INF. However, there was an increased incidence of vomiting and deeper levels of sedation when compared to published data of single-agent use of N(2)O, which could lead to more serious adverse events. Further investigation is needed to establish the analgesic efficacy of combining N(2)O and INF and to clarify the safety profile before this combination can be recommended for PSA in children.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Anesthesia / administration & dosage*
  • Administration, Intranasal
  • Adolescent
  • Anesthetics, Inhalation / administration & dosage*
  • Chi-Square Distribution
  • Child
  • Child, Preschool
  • Conscious Sedation / methods*
  • Emergency Service, Hospital
  • Female
  • Fentanyl / administration & dosage*
  • Humans
  • Infant
  • Male
  • Nitrous Oxide / administration & dosage*
  • Pilot Projects
  • Prospective Studies
  • Statistics, Nonparametric


  • Adjuvants, Anesthesia
  • Anesthetics, Inhalation
  • Nitrous Oxide
  • Fentanyl