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Combined nitrous oxide 70% with intranasal fentanyl for procedural analgosedation in children: a prospective, randomised, double-blind, placebo-controlled trial
  1. Michelle Seiler1,
  2. Georg Staubli1,
  3. Markus A. Landolt2,3
  1. 1 Pediatric Emergency Department, University Children’s Hospital Zurich, Zurich, Switzerland
  2. 2 Department of Psychosomatics and Psychiatry, University Children’s Hospital Zurich, Zurich, Switzerland
  3. 3 Division of Child and Adolescent Health Psychology, Department of Psychology, University of Zurich, Zurich, Switzerland
  1. Correspondence to Dr Michelle Seiler, Pediatric Emergency Department, University Children’s Hospital Zurich, Zurich 8032, Switzerland; michelle.seiler{at}


Objective Nitrous oxide 70% (N2O 70%) is an excellent medication for procedural analgosedation (PAS), yet the limit of its analgesic power remains uncertain; therefore, a combination with intranasal fentanyl (INF) was suggested. However, this combination seems to result in a higher rate of vomiting and deeper sedation. This study aimed at assessing the analgesic efficacy, sedation depth and rate of adverse events of PAS with N2O 70% with and without INF.

Methods Patients aged 2–16 years who qualified for PAS with N2O 70% were randomly assigned to receive either INF or placebo prior to N2O inhalation in this randomised, double-blind study, which was performed in a tertiary children’s hospital ED between September 2015 and October 2017. Behaviour during the procedure was evaluated using the Face, Leg, Activity, Cry and Consolability (FLACC) scale and the Modified Behavioural Pain Scale (MBPS); analgesic efficacy was assessed with a self-reported pain scale. Sedation depth using the validated University of Michigan Sedation Scale and adverse events in the ED and during the following 12 hours were documented.

Results A total of 402 patients were included; 3 did not tolerate N2O and therefore had to be excluded. Overall, 399 patients were analysed, of whom 201 (50.4%) received INF. No significant group differences with regard to FLACC scale score, self-reported pain, MBPS score and sedation depth were found. In addition, the two groups did not differ with regard to all types of adverse events.

Conclusion Combining N2O 70% with INF resulted in no differences with regard to FLACC scale score, self-reported pain, MBPS score, patient and parental satisfaction rate, sedation depth, and adverse events.

Trial registration number NCT02533908

  • paediatrics, paediatric emergency medicine
  • paediatrics
  • paediatric injury
  • pain management

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  • Contributors MS and GS conceptualised and designed the study, collected the data, drafted the initial manuscript, and reviewed and revised the manuscript. MAL carried out the statistical analyses, and reviewed and revised the manuscript. MS, GS and MAL approved the final manuscript as submitted and agree to be accountable for all aspects of the work.

  • Funding This study was supported by a grant from the Children’s Research Center (CRC) of the University Children’s Hospital Zurich.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement There are no additional unpublished data from the study.