Nitric Oxide Monitoring Fails To Help Most Children Suffering from Asthma

A new study has found that calibrating medications based on daily monitoring of fractional exhaled nitric oxide (FENO) and symptoms in asthmatic children showed no significant improvement over medicating based on daily symptom monitoring alone.

Researchers at the Erasmus University Medical Center-Sophia Children's Hospital (Rotterdam, The Netherlands) conducted a multi-center prospective study that randomized 151 children from 15 academic centers and hospitals with mild to moderate asthma to two groups. The first group of children was monitored daily for symptoms, while the other was additionally monitored daily for FENO levels. Families were called every three weeks and reported on the daily symptoms during the prior three weeks; the child's medication was adjusted accordingly. The researchers compared the rates of exacerbation, symptoms, use of medications and other endpoints during the last 12 weeks of the study in the two groups.

The results showed that there were no significant differences whether or not FENO had been part of the daily monitoring. However, both groups enjoyed an impressive overall improvement in symptoms, despite a reduction of about 50% in inhaled steroid dose, suggesting considerable benefit of frequent monitoring. The FENO group, however, did have nearly twice as many dosage changes as the symptom-only group, which according to the researchers supports the idea that the lack of difference may be a reflection on the limits of compliance, rather than an inherent limitation in the technique. The study was published in the January 15, 2009 issue of the American Journal of Respiratory and Critical Care Medicine.

"We speculate that daily supervision and frequent phone contacts have produced an improvement that could not be beaten by additional monitoring of FENO, most likely because of a ceiling effect on compliance,” said lead author Johan de Jongste, M.D., Ph.D. "We did not address other possible applications of frequent FENO monitoring, such as prediction of steroid effect, loss of control, prediction, and prevention of exacerbations, and tapering of steroids in symptom-free children who wheezed in the past.”

The level of nitric oxide (NO) in the exhaled breath of an asthmatic person can warn of worsening asthma symptoms, and may even signify an imminent attack linked to underlying airway inflammation. This has made the monitoring of NO levels, particularly in children, of significant interest as a potential way to help clinicians fine-tune medications and improve treatment outcomes.

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Erasmus University Medical Center-Sophia Children's Hospital