呼出气一氧化氮检测在慢性咳嗽病因诊断中的价值

目的评估呼出气一氧化氮（FeNO）检测在慢性咳嗽患者病因诊断中的价值。方法选取2009年1月～2009年4月因慢性咳嗽在我院进行支气管激发试验的患者43例，先后予以FeNO、支气管激发试验检查。结果18例患者支气管激发试验阳性，诊断为咳嗽变异性哮喘。25例激发试验阴性患者，为非哮喘的慢性咳嗽。哮喘组患者FeNO水平显著高于非哮喘组，哮喘组患者FeNO值与LogPD20FEV1存在显著负相关性（r=-0．884）。FeNO诊断咳嗽变异性哮的最佳阈值为15．85ppb，其约登指数为0．753，灵敏度为83．3％，特异度为92．0％，阳性预计值为88．2％，阴性预计值88．5％。结论FeNO对咳嗽变异性哮的诊断具有较高的灵敏度和特异度，在慢性咳嗽的病因诊断中具有重要的应用价值。

The etiological diagnosis value of fractional exhaled nitric oxide test in patients with chronic cough

Objective To evaluate the etiological diagnosis value of exhaled nitric oxide（FeNO） test in patients with chronic cough. Method To select subjects with chronic cough accepting bronchial provocation test from January to April 2009.43 cases were enrolled on the basis of selection/exclusion criteria. Result 18 eases with the positive results of bronchial provocation test were diagnosed as cough variant asthma（CVA） according to the guideline. 25 eases with the negative results were exclude from asthma. The level of FeNO of the asthma group was significantly higher than those of the non-asthma group. A negative correlation was found between the level of FeNO and LogPD20FEV1 in the eases with airway hyperre- sponsiveness（r = -0. 884）. The area under ROC curve was 0. 913. The optimal threshold for diagnosing asthma was 15.85ppb with Youden＇ s index of 0. 753, sensitivity of 83.3% , specificity of 92.0%, positive predictive value of 88.2%, negative predictive value of 88.5%. Conclusion FeNO test has a high sensitivity and specificity in the diagnosis of CVA, which contributes to the etiological diagnosis of chronic cough.