The Diagnostic Value Of Fractional Exhaled Nitric Oxide(FeNo) Detection In Asthma-chronic Obstructive Pulmonary Disease Overlap(ACO)

Objective: To investigate the diagnostic value of fractional exhaled nitric oxide(FeNO)detection in asthma-chronic obstructive pulmonary disease overlap(ACO).Methods: A total of 259 subjects in the Affiliated Hospital of Southwest Medical University from January 2017 to January 2018 were selected as the objects of study,62 patients in AECOPD group,46 patients with acute bronchial asthma,40 patients with acute ACO group,40 patients with bronchiectasis,35 patients with pulmonary infection,and 36 healthy controls.The difference in FeNO values among different groups of common pulmonary diseases and the difference of FeNO value in ACO patients under different pulmonary function classification were measured and analyzed.The ROC curves was used for diagnosis of COPD and ACO and the critical value of FeNO level in ACO.Result: 1.The FeNO level in ACO group(38.58±8.42 ppb)was higher than that in COPD group(19.02±5.12 ppb,P<0.05),and lower than that in bronchial asthma group(71.67±16.82 ppb,P<0.05),and higher than that in bronchiectasis group(27.0±5.27 ppb),pulmonary infection group(27.74±6.11 ppb)and normal control group(25.31±4.78 ppb)(P=0.00<0.05).2.There was no significant difference in FeNO level among bronchiectasis group,pulmonary infection group(P>0.05)and normal control group(P=0.89>0.05).3.The predicted value of FEV1% in ACO group was lower than that in COPD group(56.02±14.56,P<0.05),bronchial asthma group(69.51±13.58,P < 0.05)and normal control group(90±4.66,P < 0.05).4.In ACO,the FeNO value in GOLD IV group(46.88±9.87 ppb)was higher than that in GOLD II group(36.26 +7.07 ppb,P< 0.05)and GOLD III group(36.85+6.55 ppb,P<0.05).5.The FeNO =23.5 ppb was used as the critical point,the sensitivity and specificity of identifying COPD and ACO was 82.3% and 79.7%,respectively.The FeNO=33.5 ppb was used as the critical point,the sensitivity and specificity of identifying ACO and non-bronchial asthmatic pulmonary diseaseswas 72.5% and 83%,respectively.Conclusion: Fractional exhaled nitric oxide(FeNO)detection as a non-invasive,safe and simple method can be used to differentiate asthma-chronic obstructive pulmonary disease overlap(ACO)from other non-bronchial asthma common pulmonary diseases such as chronic obstructive pulmonary disease.In ACO,the level of FeNO may be correlated with the degree of airflow limitation.