Exhaled nitric oxide in the management of childhood asthma: A prospective 6‐months study

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Abstract
Fractional exhaled nitric oxide (FeNO) is elevated in asthma and reflects eosinophilic airway inflammation. The aim of this prospective, randomized, single‐blind study was to examine whether the inclusion of repeated FeNO measurements into asthma monitoring leads to an improvement in asthma outcome. Forty‐seven children with mild to moderate asthma were allocated to a FeNO group (n = 22) and to a control group (n = 25). In the FeNO group therapy was based on symptoms, β‐agonist use, lung function, and FeNO whereas in the control group therapy was based on symptoms, β‐agonist use and lung function only. Patients performed five visits in 6 weeks intervals. Frequency of respiratory symptoms, β‐agonist use, FEV1% predicted and the frequency of exacerbations were similar between groups. Patients in the FeNO group received higher doses of inhaled corticosteroids (ICS) (control group: median (interquartile range): 241 µg (26–607 µg); FeNo group: 316 µg (200–500 µg) and had significantly higher MEF50% predicted (control group: median (interquartile range): 68.5% (55.8–83.1%); FeNO group: 83.2% (62.9%–98.3%). At a cut‐off point of 22.9 ppb FeNO the best predictive value for exacerbations with a sensitivity of 80% and specificity of 60% was found. Significant relationships were observed between FeNO and dose of ICS (β = −8.77; P < 0.002), β‐agonist use 2 weeks prior to a visit (β = 0.11; P < 0.05), asthma symptoms (β = 0.02; P < 0.0001), and bronchial hyperresponsiveness (β = 0.04; P = 0.02). In conclusion, FeNO was related to important markers of asthma control. A therapy regimen aimed at lowering FeNO in children with asthma improved parameters of small airway function, but was not able to improve clinical markers of asthma control. Pediatr Pulmonol.