According to results reported in the second issue for January of the American Journal of Respiratory and Critical Care Medicine, a publication of the American Thoracic Society, nitric oxide (NO) level in the exhaled breath of an individual suffering from asthma can portend worsening of asthma symptoms besides signifying an imminent attack linked to underlying airway inflammation.

From News-Medical.Net:

The researchers compared the rates of exacerbation, symptoms, use of medications and other endpoints between the last 12 weeks in the two groups. 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 percent in inhaled steroid dose, suggesting considerable benefit of frequent monitoring.

“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,” wrote Dr. de Jongste.

The FENO group did, however, have nearly twice as many dosage changes as the symptom-only group, which 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. Still, the added cost and apparent lack of benefit of daily FENO monitoring found in this study suggests that applying the technique in this way is not of benefit to the asthmatic population at large, when compared to daily symptom monitoring.

Johan C. de Jongste, M.D., Ph.D., at the Erasmus University Medical Center-Sophia Children’s Hospital in the Netherlands, and colleagues randomized 151 children from 15 academic centers and hospitals affected with mild to moderate asthma during a monitoring course lasting for 30 weeks.