Nitrous oxide is an anesthetic gas that has been used extensively to decrease pain during dental procedures. Recent publications report that nitrous oxide administration to pediatric patients is safe and effective in reducing pain and anxiety associated with a variety of medical procedures. We completed a randomized, crossover, pilot study in our outpatient clinic to compare the efficacy of nitrous oxide (N2O) to standard conscious sedation (SCS) in providing analgesia during lumbar puncture (LP) in children with leukemia and lymphoma.

Two nurses evaluated 12 subjects during a N2O LP and 10 subjects during a SCS LP (midazolam and either fentanyl or morphine). Inter-nurse reliability was not different for any measure. The mean time for clinic visit was statistically shorter for the N2O group, 34 minutes, compared to 57 minutes for SCS (p=0.010). The mean length of procedure was 9 minutes using N2O or SCS. The type of sedation did not affect the difficulty performing the LP. The incidence of side effects (nausea, vomiting, combative behavior, and unsteadiness when leaving for home) was similar in the N2O and SCS groups. Pain control was equivalent. The nurse, parent, and subject reported pain during the procedure as zero for 5/12 subjects with N2O and 3/10 subjects with SCS. Parents and subjects were very satisfied with N2O (parent=1.8, child=2.8) and SCS (parent=1.5, child=2.2) sedation (10-point Likert scale with 1=very satisfied, 10=very dissatisfied). After completion of both procedures, 8/12 subjects preferred N2O whereas 2/10 preferred SCS. All twelve subjects who received N2O returned to normal activity within an hour of leaving the clinic and 3/10 subjects who received SCS required longer than one hour.

Nitrous oxide is effective in reducing procedural pain with few side effects while decreasing time required for clinic visit and return to normal activity. Patient and parent satisfaction was high with more patients and families preferring N2O sedation to SCS.

Parent and Nurse Mean Pain Scores Before, During, and After Lumbar Puncture Using N2O and SCS (10-point Likert Scale)

Pre-Procedure PainDuring Procedure PainPost-Procedure Pain
ParentNurseParentNurseParentNurse
N20.3 1.4 0.9 0.5 0.3 
SCS 0.3 0.1 2.5 1.9 1.5 0.7 
Pre-Procedure PainDuring Procedure PainPost-Procedure Pain
ParentNurseParentNurseParentNurse
N20.3 1.4 0.9 0.5 0.3 
SCS 0.3 0.1 2.5 1.9 1.5 0.7 

Disclosure: No relevant conflicts of interest to declare.

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