Clinical Application Of FeNO In Pediatric Chronic Airway Inflammatory Diseases

Objective We investigate the clinical application of fractional exhaled nitric oxide(FeNO)in pediatric chronic airway inflammatory diseases,evaluate the impact of FeNO assessments on diagnosis and differential diagnosis of bronchial asthma and chronic cough,the influence to FeNO level by allergic factors,the change of FeNO level after inhaled corticosteroids(ICS)treatment.Finally our study has high guidance value on the use of FeNO in standardized diagnosis,treatment and management of pediatric chronic airway inflammatory diseases.Method 282 children were collected,who aged from 5 to 12 years received FeNO test in September 2014 to December 2015 in our outpatient department,including: 173 samples of bronchial asthma(group A),which were divided into 75 samples of chronic persisetent bronchial asthma combined with allergic rhinitis(group A1),20 samples of chronic persisetent asthma with no allergic rhinitis(group A2),78 samples of bronchial asthma at clinical remission stage(group A3);109 samples of chronic cough(group B),which were divided into 29 samples of cough variant asthma(group B1),46 samples of upper airway cough syndrome(group B2),30 samples of(respiratory)post-infection cough(group B3).While some children of group A and B also received the testes of peripheral blood eosinophil percentage,the serum levels of allergen-specific IgE(sIgE)and lung function(FEV1%)for diagnosis.50 samples of healthy children were choosed as the control group(group C).Results(1)Comparison of FeNO level between Group A and Group C: FeNO level of group A1,A2,A3 was significantly higher than group C(P<0.01).Comparison within group A,FeNO level of group A1 was higher than group A2 and A3,FeNO level of group A2 was higher than group A3(P<0.05).(2)Comparison of FeNO level between Group B and Group C: FeNO level of group B1 and B2 was significantly higher than group C(P<0.01).There was no significant difference between group B3 and group C(P>0.05).Comparison within group B: there was no significant difference between group B1 and B2(P>0.05),FeNO level of group B1 and B2 was higher than group B3(P<0.01).(3)FeNO level of allergen-positive children was significantly higher than the allergen--negative children(Z=-8.532,P<0.001).FeNO level of bronchial asthma combined with allergic rhinitis was significantly higher than asthma with no allergic rhinitis(P<0.05).FeNO level had a significant positive correlation with s Ig E(r=0.72,P<0.05);FeNO level had a significant positive correlation with EOS%(r=0.51,P<0.05);(4)FeNO level of asthma was significantly reduced after 1 month and 3 months of ICS treatment,there was significant difference with that before treatment(P<0.05),there was still significant difference between asthma after ICS treatment and the healthy control group(P<0.05).FeNO level had no significant correlation with FEV1% before ICS treatment or after 1 month and 3 months of ICS treatment(r=-0.06、0.24、0.09,P>0.05).Conclusion As an airway inflammation signal,FeNO level could reflect the degree of airway eosinophil inflammation,be used in diagnosis and differential diagnosis of pediatric chronic airway inflammatory diseases,and improve the diagnosis efficiency of bronchial asthma,CVA,allergic rhinitis and NAEB.Considering FeNO level was affected by allergic factors,when we use FeNO to guide the diagnosis and treatment of asthma,we should give full consideration of allergic factors,such as allergic rhinitis.FeNO level was significantly reduced after ICS treatment,which could be dynamically monitored in response to airway inflammation and treatment compliance.FeNO level had no significant correlation with lung function(FEV1%).If combine FeNO with the traditional pulmonary function tests,we could assess the severity of asthma more accurately.