[呼出气一氧化氮分数在慢性咳嗽诊断中的价值]

Zhang Yong-Ming, Lin Jiang-Tao, Su Nan, Chen Xin, Liu Guo-Liang, Yu Hong-Xia, Nong Ying, Zhang Xiao-Yan, Yang Meng, He Jie, Li Yi-Ming

Graduate School, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100730, China.

Zhonghua Yi Xue Za Zhi. 2011 May 17;91(18):1254-8.

OBJECTIVE

To evaluate the diagnostic value of fractional exhaled nitric oxide (FeNO) in the diagnosis of chronic cough.

METHODS

A total of 106 subjects with chronic cough and normal chest radiographs were recruited from October 2009 to September 2010. Based on the management guidelines of the Chinese Respiratory Society for cough, the golden standard methods were used to make the definite diagnosis of chronic cough, including sputum cell counts, pulmonary function tests, bronchial hyperresponsiveness, 24-h esophageal pH monitoring, skin pricking test and serum immunoglobulin E. All subjects received a FeNO test by a NIOXMINO analyzer. The values of FeNO to diagnose cough variant asthma (CVA) from chronic cough and EB from non-asthma cough were respectively assessed by the receiver operating characteristic (ROC) curves.

RESULTS

Among them, the definite diagnoses were cough variant asthma (CVA, n = 39), eosinophilic bronchitis (EB, n = 30) and other causes (n = 37). The FeNO levels in CVA [(54 ± 21) ppb)] (1 ppb = 1 × 10(9) mol/L) were significantly higher than those in EB [(34 ± 17) ppb, P < 0.01] and other causes [(21 ± 10) ppb, P < 0.01]. And the FeNO levels in EB were higher than those in other causes (P < 0.01). To diagnose CVA from chronic cough, the optimal FeNO cutoff value was 40 ppb with a sensitivity of 75%, a specificity of 86%, a positive predictive value of 77%, a negative predictive value of 86% and an accuracy of 81%. To diagnose EB from non-asthma chronic cough, the optimal FeNO cutoff value was 31 ppb with a sensitivity of 63%, a specificity of 92%, a positive predictive value of 88%, a negative predictive value of 92% and an accuracy of 72% respectively.

CONCLUSION

There are significant differences between the FeNO levels of different causes of chronic cough. A marked elevation of FeNO level helps to make a final diagnosis of CVA or EB. FeNO test is useful for making the diagnosis and differential diagnosis of chronic cough in clinic practices.

目的

评估呼出气一氧化氮分数（FeNO）在慢性咳嗽诊断中的价值。

方法

2009年10月至2010年9月共纳入106例慢性咳嗽且胸部X线片正常的受试者。依据中华医学会呼吸病学分会咳嗽的诊治指南，采用金标准方法对慢性咳嗽进行明确诊断，包括痰细胞计数、肺功能检查、支气管高反应性、24小时食管pH监测、皮肤点刺试验及血清免疫球蛋白E检测。所有受试者均采用NIOXMINO分析仪进行FeNO检测。通过绘制受试者工作特征（ROC）曲线分别评估FeNO用于鉴别慢性咳嗽中的咳嗽变异性哮喘（CVA）及非哮喘性咳嗽中的嗜酸粒细胞性支气管炎（EB）的价值。

结果

其中，明确诊断为咳嗽变异性哮喘（CVA，n = 39）、嗜酸粒细胞性支气管炎（EB，n = 30）及其他原因（n = 37）。CVA组的FeNO水平为（54±21）ppb（1 ppb = 1×10⁻⁹mol/L），显著高于EB组[（34±17）ppb，P < 0.01]及其他原因组[（21±10）ppb，P < 0.01]。且EB组的FeNO水平高于其他原因组（P < 0.01）。鉴别慢性咳嗽中的CVA，FeNO的最佳截断值为40 ppb，敏感性为75%，特异性为86%，阳性预测值为77%，阴性预测值为86%，准确性为81%。鉴别非哮喘性慢性咳嗽中的EB，FeNO的最佳截断值为31 ppb，敏感性为63%，特异性为92%，阳性预测值为88%，阴性预测值为92%，准确性为72%。