The interpretation of exhaled nitric oxide values in children with asthma depends on the degree of bronchoconstriction and the levels of asthma severity
Tomasz Grzelewski, Paweł Majak, Joanna Jerzyńska, Włodzimierz Stelmach, Rafał Stelmach, Anna Janas, Aleksandra Grzelewska, Konrad Witkowski, Eusebio Makandjou-Ola, Iwona Stelmach, Tomasz Grzelewski, Paweł Majak, Joanna Jerzyńska, Włodzimierz Stelmach, Rafał Stelmach, Anna Janas, Aleksandra Grzelewska, Konrad Witkowski, Eusebio Makandjou-Ola, Iwona Stelmach
Abstract
Background: The clinical implications of fractional exhaled nitric oxide (F(ENO)) measurements in childhood asthma are unclear. We aimed to evaluate the relationship between the level of exhaled nitric oxide and pre-bronchodilator FEV1 and the change in FEV1 after bronchodilator in children with asthma.
Methods: This was a retrospective, cross-sectional study. We evaluated data from medical documentation of children with asthma with special attention to F(ENO) results, asthma severity, FEV1 (% predicted), and bronchial reversibility test.
Results: Four hundred and five subjects (age 6-18 y) completed the study. Median levels of F(ENO) increased linearly with subjects' age (P = .03). We found a nonlinear trend of pre-bronchodilator FEV1 across 4 quartiles of F(ENO) in episodic and mild asthma; we observed lower pre-bronchodilator FEV1 in children with higher F(ENO), but only up to the F(ENO) value of 35.4 ppb; in children with F(ENO) value > 35.4 ppb, pre-bronchodilator FEV1 was increased. We found a linear increasing trend of change from baseline (after 400 μg of salbutamol) in FEV1 across F(ENO) categories in children with moderate asthma.
Conclusions: Our results suggest a need to measure F(ENO) before as well as after spirometry. Consequently, in children with asthma with bronchial obstruction, we suggest assessing F(ENO) after short-acting β2 agonists as well. (ClinicalTrials.gov registration NCT00815984.).
Keywords: FENO; FEV1; airway caliber; asthma; asthma severity; children; glucocorticosteroids.
Copyright © 2014 by Daedalus Enterprises.
Source: PubMed