呼出气一氧化氮检测对支气管哮喘的诊断价值

目的 以现行哮喘诊断方法为对照.评估呼出气一氧化氮(FeNO)浓度检测诊断支气管哮喘的临床价值.方法 纳入四川大学华西医院呼吸科门诊2008年8～9月有喘息、气紧、咳嗽等疑似支气管哮喘的患者101例.使用NO测定仪(Aeroerine AB;Solna,Sweden)测定FeNO水平,检测过程严格按照美国胸科协会制定的指南进行.以临床症状和支气管激发试验或舒张试验为哮喘诊断的金标准,绘制ROC曲线,结合ROC曲线评价FeNO对支气管哮喘的鉴别诊断价值,明确FeNO的诊断临界点.结果 101例患者中,激发试验阳性38例.支气管舒张试验阳性10例,临床诊断为支气管哮喘.其余53例为激发试验阴性者,为非哮喘.哮喘组FeNO高于非哮喘组(68.19±43.00)ppb比(19.52±10.60)ppb,P<0.05].激发试验阳性者FeNO值与InPD20FEV1间存在线性关系.ROC曲线下面积为0.9,最佳临界点为36.5 ppb,以该点为阈值,诊断哮喘的敏感度为92.7%,特异度为83.3%,阳性预测值79.17%,阴性预测值94.34%,准确度87.13%.结论 FeNO对支气管哮喘的诊断和鉴别诊断具有较高的敏感性和特异性.

The Diagnostic Value of the Fractional Exhaled Nitric Oxide for Asthma

Objective To determine the diagnostic value of fractional exhaled nitric (FeNO) measurement in diagnosis of bronchial asthma. Methods The patients with unkown-cause respiratory symptoms including wheezing, cough, and breathlessness were enrolled from August to September in 2008. FeNO was measured by nitric oxide analyzer (NIOX; Aerocrine AB; Solna, Sweden). Bronchial challenge test (BCT) or bronchodilator test was defined as golden standard for asthma diagnosis. The value of FeNO was assessed and the optimal operating point of FeNO testing was determined by the means of the receiver operating characteristic (ROC) curves. Results A total of 101 patients were enrolled, in which 48 cases were diagnosed as asthma by positive yield in BCT (in 38 cases) or bronchodilator test (in 10 cases). The severity of airway hyperresponsiveness (AHR) judged by BCT was mild in 15 cases, moderate in 15 cases and severe in 8 cases. The levels of FeNO of asthma group were higher than those of non-asthma group (68.19±43.00) pph vs (19.52±10.60) ppb, P < 0.05]. A linear correlation of FeNO with lnPD20 FEV1 was revealed in the cases with AHR. Area under ROC curve was 0.9. The optimal diagnostic cutoff point was 36.5 ppb which was capable of differentiating asthma and non-asthma with sensitivity of 92.7%, specificity of 83.3%, positive predictive value of 79.17% , negative predictive value of 94.34% and accuracy of 87.13%. Conclusion FeNO test may be helpful in the diagnosis of asthma with high sensitivity and specificity.