• nitrous;
  • oxide;
  • analgesia;
  • pediatric sedation;
  • anxiety;
  • laceration;
  • wound;
  • emergency department


Objective: To determine the effect of an inhaled 50% nitrous oxide/50% oxygen mixture on measures of observed anxiety in children during laceration repair.

Methods: A prospective, randomized, placebo-controlled, double-blind comparison of an inhaled 50% nitrous oxide/50% oxygen mixture (treatment group) with 100% oxygen (control group) during repair of lacerations was performed. The study population was a convenience sample of children aged 2–7 years in an urban pediatric ED. The primary outcome variable was the change in scores before and during laceration repair with a 10-point modified Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) assessment. The secondary outcome variable was a 4-point anxiety scale measured before and during the procedure.

Results: Thirty patients were entered into the study. Seventeen children inhaled the 50% nitrous oxide/oxygen mixture and 13 inhaled 100% oxygen during laceration repair. There was no statistically significant difference in initial CHEOPS and anxiety scores between the 2 groups (p = 0.687 and 0.809, respectively). The median CHEOPS scores in the treatment group decreased by 5 points, while those of the control patients increased by 3 (p < 0.001). The median anxiety scores in the treatment population decreased by 1 point, with an increase of 1 for the control patients (p < 0.001).

Conclusion: Administration of a 50% nitrous oxide/50% oxygen mixture to children during their laceration repair resulted in a significant decrease in measures of anxiety when compared with inhalation of 100% oxygen.