The Use of Nitrous Oxide To Treat Pain of Lumbar Punctures in Ambulatory Pediatric Leukemia and Lymphoma Patients.

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.