Value of FeNO combined with lung function test in the diagnosis of small airway lesions and etiology in patients with chronic cough

ObjectiveTo investigate the value of fractional exhaled nitric oxide(FeNO)combined with pulmonary function test in the diagnosis of small airway lesions and etiology in patients with chronic cough.

MethodsOne hundred and sixty-six patients with chronic cough were divided into the small airway lesion group and no small airway lesion group according to the results of pulmonary function test.The correlation between FeNO and small airway function indexes, sputum-induced EOS and IgE level in small airway lesion group were analyzed.The ROC curve was used to analyze the predictive value of FeNO level in small airway lesion patients with chronic cough.The value of FeNO in the diagnosis of chronic cough was analyzed.

ResultsThe ROC curve was used to analyze small airway lesion by FeNO, the results showed that the area under the curve was 0.776, and the 95%CI was 0.720-0.832.The optimal threshold of FeNO in predicting small airway lesion was 29.0 ppb, and the corresponding sensitivity and specificity were 60.7% and 82.5%, respectively.The ROC curve of FeNO in diagnosing the CVA during chronic cough was analyzed, the results showed that the area under the curve was 0.902, and the 95% CI was 0.864-0.935.The optimal threshold of FeNO in predicting CVA was 40.1 ppb, the corresponding sensitivity and specificity were 83.3% and 86.7%, respectively.

ConclusionsFeNO combined with pulmonary function test is of great value in the diagnosis of chronic cough small airway lesion.