Fractional exhaled nitric oxide (FeNO) may predict exercise-induced bronchoconstriction (EIB) in schoolchildren with atopic asthma

Department of Pediatrics and Allergy, Medical University of Lodz, N. Copernicus Hospital, Lodz, Poland.
Nitric Oxide (Impact Factor: 3.52). 05/2012; 27(2):82-7. DOI: 10.1016/j.niox.2012.05.002
Source: PubMed


There is a need for the performance of exercise-induced bronchoconstriction (EIB) tests in the monitoring of childhood asthma control. We aimed to evaluate whether in children with atopic asthma, EIB can be predicted by one or more of the following parameters or by their combination: fractional exhaled nitric-oxide (FeNO), allergy profile, asthma treatment, total IgE serum concentration and eosinophil blood count (EBC).
It was a retrospective, cross-sectional study. We evaluated data from medical documentation of children with atopic asthma who had performed standardized spirometric exercise challenge test.
One hundred and twenty six patients with atopic asthma, aged 5-18, were included in the analysis. There were two groups of patients: the EIB group (n=54) and the no-EIB group (n=72). The median FeNO level prior to exercise in the EIB group was 27.6 vs. 16.3 ppb in the no-EIB group (p=0.002). FeNO level higher than 16 ppb had the highest diagnostic value to confirm EIB. When using the FeNO level of >16 ppb, the sensitivity, specificity, negative predictive and positive predictive values for EIB were 83%, 46.9%, 74.2%, and 60%, respectively. In the EIB group, the degree of FeNO elevation did correlate positively with the absolute fall in FEV(1) (p=0.002; r=0.45). The FeNO value of >16 ppb, EBC value of >350 cell/mm(3) and allergy to house dust mites presented the highest odds ratios of EIB. However, the FeNO value of >16 ppb was the only independent odds ratio of EIB.
Elevated FeNO level increased the odds of EIB in asthmatic schoolchildren, independently of other asthma severity markers and the intensity of anti-asthma therapy. It seems likely that FeNO measurement may act as a screening tool and help to prevent under-diagnosis and under-treatment of exercise-induced bronchoconstriction in schoolchildren with atopic asthma.

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    • "Several studies showed an inverse correlation between FeNO levels and bronchial hyperreactivity tests in children [58,70-76], and only one group did not confirm this finding [77]. Nevertheless, elevated FeNO levels increase the probability of exercise-induced bronchoconstriction in asthmatic school-age children [78]. These conflicting results may be explained with the different methods used to measure FeNO as well as with the heterogeneity of the study populations, in particular regarding the presence of atopy and the use of steroids. "
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    ABSTRACT: Fractional exhaled nitric oxide (FeNO) is a non invasive method for assessing the inflammatory status of children with airway disease. Different ways to measure FeNO levels are currently available. The possibility of measuring FeNO levels in an office setting even in young children, and the commercial availability of portable devices, support the routine use of FeNO determination in the daily pediatric practice. Although many confounding factors may affect its measurement, FeNO is now widely used in the management of children with asthma, and seems to provide significantly higher diagnostic accuracy than lung function or bronchial challenge tests. The role of FeNO in airway infection (e.g. viral bronchiolitis and common acquired pneumonia), in bronchiectasis, or in cases with diffuse lung disease is less clear. This review focuses on the most recent advances and the current clinical applications of FeNO measurement in pediatric lung disease.
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    ABSTRACT: The fractional concentration of exhaled nitric oxide (FENO), a known marker of atopic-eosinophilic inflammation, may be used as a surrogate to assess exercise-induced bronchoconstriction (EIB) in asthmatic children. The predictive value of baseline FENO for EIB appears to be influenced by several factors, including age, atopy, current therapy with corticosteroids and measurement technique. Nonetheless, FENO cut-off values appear to be able to rule out EIB. FENO levels decrease during EIB, apparently through neural mechanisms rather than by decreased airway-epithelial surface. Partition of FENO into proximal and peripheral contributions of the respiratory tract may improve our understanding on NO exchange during exercise and help to screen subjects prone to EIB. Other biomarkers of inflammation and oxidative stress contained in exhaled gases and exhaled breath condensate (EBC) may shed light on the pathophysiology of EIB. Exhaled breath temperature is a promising real-time measurement whose routine use for assessing EIB warrants further investigation.
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    ABSTRACT: The clinical implications of FeNO measurements in childhood asthma are unclear. AIM:: 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. It 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 (BRT). Four hundred and five subjects (aged 6-18) completed the study. Median levels of FeNO increased linearly with subjects' age (p=0.025). We found a non-linear trend of pre-bronchodilator FEV1 across four 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 higher than 35.4 ppb, pre-bronchodilator FEV1 was increased. We found a linear increasing trend of change from baseline (after 400 mcg of salbutamol) in FEV1 across FeNO categories in children with moderate asthma. 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 also after short-acting Beta2-agonists.
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