RT Journal Article SR Electronic T1 The Interpretation of Exhaled Nitric Oxide Values in Children With Asthma Depends on the Degree of Bronchoconstriction and the Levels of Asthma Severity JF Respiratory Care FD American Association for Respiratory Care SP 1404 OP 1411 DO 10.4187/respcare.02889 VO 59 IS 9 A1 Tomasz Grzelewski A1 Paweł Majak A1 Joanna Jerzyńska A1 Włodzimierz Stelmach A1 Rafał Stelmach A1 Anna Janas A1 Aleksandra Grzelewska A1 Konrad Witkowski A1 Eusebio Makandjou-Ola A1 Iwona Stelmach YR 2014 UL http://rc.rcjournal.com/content/59/9/1404.abstract 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.)