BACKGROUND Migraine headaches account for 8-18% of all headaches seen in pediatric emergency rooms. Standard treatment includes IV pain medications, anti-emetics, and IV fluids. Nitrous oxide has analgesic properties similar to those of opioids and is easy to administer. It has been shown in two small studies to be effective in treating migraine headaches.

RESEARCH QUESTION Does nitrous oxide act as a safe, less invasive, and effective treatment of acute migraine headaches in children and adolescents presenting to an Emergency Department?

DESIGN This is a prospective non-randomized self-controlled study. Repeated measures will be taken to examine change in pain scores before and after nitrous oxide treatment.

METHODS Each participant will be given nitrous oxide until he/she reports a pain score of zero or up to fifteen minutes. Study subjects will be asked to rate their pain on a scale of 0-10 before the treatment and after the treatment at multiple time-points.

Inclusion Criteria:

• During the study enrollment period, eligible subjects will be English-speaking children and adolescents
• Between the ages of 8 - 18 years (inclusive)
• With history of migraine present for at least one year
• With previous migraine headaches conforming to ICHD-II diagnostic criteria
• Able to give assent according to institutional guidelines, and
• Have parental consent to participate.

Exclusion Criteria:

• Any patients will be excluded if he/she
• Has had any neurosurgical interventions
• Has underlying seizure disorders
• Presents with a headache of a different quality than their other migraines
• Has contraindications to nitrous oxide
• Unable to complete the pain assessment
• Does not have a dependable contact number for the follow-up call