[Correlation of fractional exhaled nitric oxide with peripheral blood eosinophils and lung function in 1-3-year-old children with asthma].

OBJECTIVE: To examine fractional exhaled nitric oxide (FeNO) values in 1-3-year-old children with asthma and analyze the correlation of FeNO with peripheral blood eosinophils (EOS) and lung function in these children. METHODS: A total of 111 children aged 1-3 years with asthma were enrolled. The children were classified into acute exacerbation (n=62) and remission groups (n=49) according to their symptoms. FeNO values, lung function, and peripheral blood EOS count were measured in these children. Sixty age-matched healthy children were enrolled as the control group. RESULTS: FeNO values were significantly higher in the acute exacerbation group (24.4 ppb) than in the remission group (18.0 ppb) and the control group (13.7 ppb) (P<0.05). The FeNO values in the remission group were significantly higher than in the control group (P<0.05). FeNO values were not significantly correlated with peripheral blood EOS count and lung function parameters (PEF, TEF25, TEF50, and TEF75). CONCLUSIONS: Measurement of FeNO is useful to evaluate the disease activity in children with asthma aged 1 to 3 years, but the FeNO values are not correlated with peripheral blood EOS count and lung function.

[Utility of fractional exhaled nitric oxide in children with asthma].

OBJECTIVE: To study the utility of fractional exhaled nitric oxide (FeNO) in young children at different stages of asthma. METHODS: Fifty-eight children with newly diagnosed asthma (aged 1-3 years) at the acute exacerbation stage between April and June, 2014 were recruited. After 3 months' treatment, the children switched into the chronic persistent stage (n=34) or remission stage (n=24). Thirty aged-matched healthy children served as controls. FeNO levels and lung function were measured for all subjects. The best cut-off value of FeNO for the diagnosis of asthma was evaluated by receiver operating characteristic (ROC) curve. RESULTS: The FeNO levels in children with asthma at various stages were higher than controls (P<0.05). The FeNO levels in the acute exacerbation stage were highest, followed by the chronic persistent stage (P<0.05). FeNO level was correlated to the stages of asthma (r=-0.382, P<0.001). The cut-off value of FeNO for the diagnosis of asthma was 22.75 ppb by ROC curve, with the sensitivity of 0.933 and the specificity of 0.388. CONCLUSIONS: The children with asthma at different stages have different FeNO levels. Measurement of FeNO is useful in the diagnosis of asthma in young children.