呼出气一氧化氮检测在慢性咳嗽治疗中的应用价值

The values of fractional exhaled nitric oxide in the treatment of chronic cough

目的评估呼出气一氧化氮(FENO)检测在慢性咳嗽治疗中的应用价值。方法根据我国的咳嗽指南,纳入呼吸与危重症医学科门诊经明确诊断的慢性咳嗽患者,分别归入咳嗽变异性哮喘(CVA)组,嗜酸性粒细胞性支气管炎(EB)组及其他病因慢性咳嗽组。分别给予FENO检测、诱导痰细胞分类计数等检查,并评价咳嗽症状积分、生活质量问卷。经指南推荐的方案治疗4周后再次进行上述评价。结果共纳入87例患者。其中,诊断CVA 29例,EB 19例,其他病因慢性咳嗽39例。CVA、EB组患者吸入糖皮质激素(ICS)治疗后咳嗽缓解患者的基线FENO值为(63±42)ppb,显著高于未完全缓解患者[(28±13)ppb,t=3.91,P<0.01)]。ICS治疗后FENO下降的比例与痰嗜酸性粒细胞下降比例显著相关(r=0.54,P<0.01),与咳嗽症状积分下降比例显著相关(r=0.48,P<0.01)。以基线FENO水平预测CVA及EB患者ICS治疗反应性的受试者工作特征曲线下面积为0.91,以FENO>36 ppb为标准预测CVA或EB患者对ICS治疗有反应的敏感性为82%,特异性为93%,阳性预测值为94%,阴性预测值为87%,准确度为83%。结论 CVA和EB患者ICS治疗后FENO的下降与咳嗽症状的缓解具有良好的相关性。依据FENO水平增高可预测慢性咳嗽患者对ICS治疗有反应。

Objective To evaluates the values of fractional exhaled nitric oxide（FENO） in the treatment of chronic cough prospectively. Methods Subjects with chronic cough were recruited from the outpatient clinic of ChinaJapan Friendship Hospital. All the patients accepted FENO tests, sputum cell counts, pulmonary function tests, bronchial provocation tests, serum Ig E, cough symptom scores and Leicester Cough Questionnaire before and after treatment of 4 weeks. Results There were 29 patients with cough variant asthma（CVA）, 19 patients with eosinophilic bronchitis（EB）and 39 patients with other causes. The baseline FENO level of the subjects whose coughs were relieved after inhaled corticosteroids（ICS） therapy of 4 weeks was（63±42） ppb, significantly higher than those with bad-response [（28±13） ppb,P〈0.01]. The proportion of FENO decrease after ICS therapy was not only significantly related to the proportion of eosinophilic decrease（r=0.54, P〈0.01）, but also significantly related to the proportion of decrease of cough symptom scores（r=0.48, P〈0.01）. To distinguish the good responders from bad responders, the optimal baseline FENO cutoff value was 36 ppb, with sensitivity of 82%, specificity of 93%, positive predictive value of 94%, negative predictive value of 87%,accuracy of 83%. Conclusions There is a good relationship between the FENO decreasing levels after ICS therapy and the reliefs of cough symptoms in the CVA and EB patients. Chronic cough patients with FENO value more than 36 ppb are indicated to respond to ICS therapy.