The Value Of Fractional Exhaled Nitric Oxide Combined With Small Airway Dysfunction In Cough Variant Asthma

Objective:By analyzing the results of fractional exhaled nitric oxide and small airway function in patients with chronic cough,this paper discusses the diagnostic value of fractional exhaled nitric oxide,small airway function and the combined detection of both in cough variant asthma,so as to provide a basis for the diagnosis of cough variant asthma and the differential diagnosis of chronic cough.Methods:Selection in October 2018-in October 2019,the first hospital of Shanxi Medical University of Respiratory and Critical Care Medicine Clinics,145 patients with chronic cough,all patients underwent FeNO,lung function?ventilation function,diffusion function,impulse oscillometry,bronchial provocation tests?detection,According to the excitation test results and the CVA diagnostic criteria,the patients were divided into CVA group and non-CVA group.The differences between FeNO and lung function indicators and the correlation between FeNO and lung function indicators were statistically analyzed among the groups,and the ROC curve was drawn to evaluate the diagnostic value of FeNO,FEF_50%and the combination of FeNO and FEF_50%on cough variability.Results:1.FEV₁/FVC and FEF_50%in the cough variant asthma group were significantly lower than those in the non-cough variant asthma group,with statistically significant differences?P<0.05?.FeNO in the cough variant asthma group was significantly higher than that in the non-cough variant asthma group?P<0.05?.There was no significant difference in other lung function indexes between the two groups.2.FeNO and FEF_50%can effectively distinguish cough variant asthma from non-cough variant asthma?P<0.05?.Among them,the area under the ROC curve of FeNO for the diagnosis of cough-variant asthma was 0.631,the cut-off point was 27.50ppb,the sensitivity was 49.00%,and the specificity was 78.00%.The area under the ROC curve of FEF_50%for the diagnosis of cough-variant asthma was 0.619,the cut-off point was 74.74,the sensitivity was 43.30%,and the specificity was 80.50%?3.The area under the ROC curve of the combined diagnosis of cough variant asthma with FeNO and FEF_50%was 0.657,the sensitivity was 63.50%,and the specificity was 65.90%.The area under ROC curve of FeNO and FEF_50%diagnosis was higher than that of single index.Conclusion:1.FeNO and small airway dysfunction are valuable in the diagnosis of cough-variant asthma.2.FEF_50%,a small airway function indicator,has the highest sensitivity in the diagnosis of cough-variant asthma,and the pulse concussion technique is still not clear in the diagnosis of small airway function.3.FeNO combined with small airway function is valuable in the diagnosis of cough-variant asthma,and it is better than single examination.