PT - JOURNAL ARTICLE AU - Tomasz Grzelewski AU - Paweł Majak AU - Joanna Jerzyńska AU - Włodzimierz Stelmach AU - Rafał Stelmach AU - Anna Janas AU - Aleksandra Grzelewska AU - Konrad Witkowski AU - Eusebio Makandjou-Ola AU - Iwona Stelmach TI - The Interpretation of Exhaled Nitric Oxide Values in Children With Asthma Depends on the Degree of Bronchoconstriction and the Levels of Asthma Severity AID - 10.4187/respcare.02889 DP - 2014 Sep 01 TA - Respiratory Care PG - 1404--1411 VI - 59 IP - 9 4099 - http://rc.rcjournal.com/content/59/9/1404.short 4100 - http://rc.rcjournal.com/content/59/9/1404.full AB - BACKGROUND: The clinical implications of fractional exhaled nitric oxide (FENO) 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 FENO 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 FENO increased linearly with subjects' age (P = .03). We found a nonlinear trend of pre-bronchodilator FEV1 across 4 quartiles of FENO in episodic and mild asthma; we observed lower pre-bronchodilator FEV1 in children with higher FENO, but only up to the FENO value of 35.4 ppb; in children with FENO 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 FENO categories in children with moderate asthma. CONCLUSIONS: Our results suggest a need to measure FENO before as well as after spirometry. Consequently, in children with asthma with bronchial obstruction, we suggest assessing FENO after short-acting β2 agonists as well. (ClinicalTrials.gov registration NCT00815984.)