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Acad Emerg Med. 1998 Feb;5(2):112-7.

Effectiveness of 50% nitrous oxide/50% oxygen during laceration repair in children.

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Department of Emergency Medicine, Maine Medical Center, Portland 04102, USA.



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


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.


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).


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.

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