Role of pulmonary function and FeNO detection in early screening of patients with ACO

Measurement of fractional exhaled nitric oxide (FeNO) is a quantitative and non-invasive approach to examine airway inflammation, which is a powerful aid in diagnosing chronic disorders of airways like asthma. Diagnostic value of FeNO and relevant indices on pulmonary function in the patients with asthma and chronic obstructive pulmonary disease (COPD) was evaluated. A total of 164 patients [58 asthma, 49 COPD and 57 asthma-COPD overlap (ACO)] were randomly recruited. FeNO, pulmonary ventilation function, and bronchial diastolic function were performed. Eight indicators including FeNO, vital capacity percentage (VC%), forced vital capacity percentage (FVC%), forced expiratory volume in one second percentage (FEV1%), forced expiratory volume in one second to forced vital capacity percentage (FEV1/FVC%), maximum independent ventilation volume percentage (MVV%), the increased percentage of FEV1 after bronchial diastolic test, the increased absolute value of FEV1 after bronchial diastolic test were examined. Significant difference in VC%, FVC%, FEV1%, FEV1/FVC%, MVV%, the increased absolute value of FEV1 after bronchial diastolic test and FeNO were significantly different between patients with asthma and patients with COPD (P<0.05). There were significant differences of VC%, FVC%, FEV1%, FEV1/FVC%, MVV% and the increased percentage of FEV1 after bronchial diastolic test in cases of patients with asthma compared to ACO patients (P<0.05). There was no statistical significance on VC%, FVC%, FEV1%, FEV1/FVC%, MVV% between COPD patients and ACO patients (P>0.05). However, more importantly, the increased percentage of FEV1 after bronchial diastolic test, the increased absolute value of FEV1 after bronchial diastolic test and the alterations on FeNO were found significantly different in ACO group compared with COPD alone (P<0.05). We compared the results from pulmonary ventilation function, bronchial diastolic function examination as well as FeNO detection among 3 groups of asthma, COPD and ACO. The examination of pulmonary ventilation function and bronchial diastolic function combined with FeNO detection is helpful in the early screening of ACO.