Characteristics of lung function and exhaled nitric oxide in atypical asthma children with chest tightness or sighing breath as sole manifestation / 国际儿科学杂志

ABSTRACT

Objective To study the characteristics of pulmonary function in atypical asthmatic children with chest tightness or sighing breath as the sole presenting manifestation,and explore the diagnostic values of fractional exhaled nitric oxide (FeNO) for the atypical asthma.Methods Seventy-nine atypical asthmatic children with chest tightness as the sole presenting manifestation during January 2012 to June 2015 were selected as subjects.All of the subjects performed spirometry,FeNO measurement,total serum IgE and specific IgE determination on their first visit,and with either positive bronchial provocation test or positive bronchial dilation test.As well as 100 healthy children who perfomred FeNO measurement were selected as control group during the same period.The pulmonary function data and FeNO values were analyzed in children who were finally confirmed as atypical asthma.Results In atypical asthma children,the abnormal rate of forced expiratory flow 50％,75％ (FEF50,FEF75) and maximum mid-expiratory flow (MMEF) were 27％,43％ and 33％.Methacholine provocation dose causing a 20％ fall in FEV1 (PD20-FEV1) were 0.41 (0.19 ～0.67)mg and were positively related with MMEF(r =0.301,P =0.007).FeNO concentration in atypical asthma patients were 13.0 × 10-9 (7.0 ×10-9 ～24.0 × 10-9),higher than that in control group(P ＜0.05).Significant correlations were found between FeNO and total serum IgE (r =0.672,P =0.001).No correlations were found between FeNO and FEV1 (P ＞0.05),between FeNO and FEV1/FVC％ (P ＞0.05) or between FeNO and PD20-FEV1 (P ＞0.05).The diagnostic values of FeNO for the atypical asthma were analyzed using the receiver operating characteristic curve,the area under the curve was 0.600.Conclusion The characteristics of pulmonary function in atypical asthma are hypofunction mainly in small airway and patients with lower MMEF had higher airway hyperresponsiveness.The diagnostic values of FeNO in atypical asthma are limited.