中文摘要：

目的探讨呼出气一氧化氮（FeNO）测定对支气管哮喘-慢性阻塞性肺疾病（哮喘-慢阻肺）重叠综合征（ACOS）患者的诊断价值。 方法选取2014年11月3日至2016年9月8日在中南大学湘雅附二医院呼吸内科就诊并自愿参加研究的ACOS患者81例（ACOS组）、哮喘患者76例（哮喘组）和慢阻肺患者82例（慢阻肺组），以及健康不吸烟者39名（健康对照组）为研究对象。用无锡尚沃公司纳库伦呼气分析仪测定各组FeNO值，比较4组研究对象FeNO水平的差异；探讨利用受试者工作特征曲线（ROC）界定FeNO值测定在慢阻肺患者中诊断出ACOS的最佳界值；分析ACOS组、慢阻肺组、哮喘组的FeNO值与FEV1占预计值%及FEV1/FVC之间的相关性。 结果哮喘组、ACOS组、慢阻肺组和健康对照组的FeNO值分别为（102.3±8.2）×109、（50.2±3.2）×109、（23.7±0.6）×109和（18.5±7.1）×109，3组患者FeNO值两两比较差异均有统计学意义（均P〈0.05）。以FeNO〉29×109为折点鉴别诊断ACOS与慢阻肺的敏感度为80%，特异度为73%，阳性预测值为75%，阴性预测值为79%，准确度为77%。ACOS、慢阻肺及哮喘组的FeNO水平与FEV1占预计值%、FEV1/FVC均无明显相关性（ACOS组r值分别为0.12和0.11,均P〉0.05；慢阻肺组r值分别为0.11和0.03，均P〉0.05；哮喘组r值分别为0.06和0.08，均P〉0.05）。 结论FeNO水平有助于鉴别ACOS、慢阻肺和哮喘患者，以FeNO高于29×109为折点有利于从慢阻肺中区分出ACOS患者。

英文摘要：

Objective To explore the diagnostic value of fractionated exhaled nitric oxide （FeNO） measurement in patients with asthma-chronic obstructive pulmonary disease （COPD） overlap syndrome （ACOS）. Methods Eighty-one patients with ACOS, 76 patients with asthma, 82 patients with COPD and 39 healthy non-smoking subjects were recruited in the study. Naku Lun breath analyzer was used to measure the level of FeNO in the 4 groups. Pulmonary function was also measured. The ROC curve was used to differentiate ACOS from patients with COPD. The correlation between FeNO and lung function was analyzed with Pearson correlation analysis. Results The levels of FeNO in asthmatic group, COPD group, ACOS group and fieahhy group were （ 102. 3±8.2 ） × 109, （ 23.7 ±0. 6 ） × 109, （ 50. 2 ±3.2 ） × 109, and （18. 5 ± 7. 1 ）× 109 respectively. Among the former 3 groups, the differences of FeNO were statistically significant （P 〈 0. 05 ）. FeNO 〉 29 ×109 was the best cutoff point to differentiate ACOS from COPD ; the sensitivity was 80% , specificity was 73 % , positive predictive value was 75 % , and negative predictive value and accuracy was 79% and 77%. There was no correlation between FeNO and FEV1% or FEV1/FVC in ACOS, COPD and asthma groups （ r = 0. 12, 0. 11, P 〉 0. 05 ; r = 0. 11,0. 03, P 〉 0. 05 ; r = 0.06, 0. 08, P 〉 0. 05 ）. Conclusion FeNO is a good marker to help clinicians differentiate ACOS from COPD. FeNO 〉 29 × 109 was the best cutoff point for the identification of patients with ACOS from COPD.