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

ABSTRACT

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.