咳嗽变异型哮喘气道反应性特点及其判定标准

Characteristics and criteria for bronchial responsivenes measurement in cough variant asthma

目的探讨比气道传导率（sGaw）测定咳嗽变异型哮喘（CVA）的气道反应性特点及阳性判定标准，并与慢性阻塞性肺疾病（COPD）患者进行鉴别。方法对30例CVA、133例典型哮喘（BA）、37例COPD、52名正常健康人行最大呼气流量容积曲线（MEFV）、气道阻力（Raw）、气道反应性测定。结果（1）缓解期CVA患者呼气流量指标［最大呼气流量（PEF）、最大呼气中段流量（MMEF）、一秒钟用力呼气容积占用力肺活量比值（FEV1／FVC）］与健康对照组比较，差异无显著性（P＞0．05）；多数（67％）CVA患者Raw增高，sGaw下降。与BA患者比较差异无显著性（P＞0．05）。（2）以35％时吸入的乙酰甲胆碱浓度（PC35SGaw）＜8g／L为界，100％CVA、BA患者呈气道局反应性，其乙酰甲胆碱（MCH）均值为1．0g／L左右；COPD组5例阳性（13．5％），阳性者MCH均值为5．24g／L。（3）以PC35sGaw＜4g／L为界，对CVA的敏感度判定为96．7％，特异度为97．3％，可信限为99％。（4）推出PC35sGaw计算公式，并与作图法比较结果完全吻合。结论以sGaw为气道反应性测定指标不但敏感，且有助于CVA与COPD的鉴别诊断，建议以PC35sGaw＜8g／L为气道反应性增高，而PC35sGaw＜4g／L为高度怀疑CVA。

To investigate the value 0f sGaw in the differentiation of CVA from COPD.Methods MEFV, airway resistance(Raw) and bronchial responsiveness were measured in 30 cases with CVA, 133cases with typical bronchial asthma(BA) and 37 cases with COPD. Results (1)The expiratory-flow parameters (PEF, MMEF, FEV1/FVC) in MEFV curve in remission period of CVA were largely normal,but most patients with CVA (67%) have increased Raw and decreased sGaw, characteristics similar with typical bronchial asthma (BA). (2) If PC35sGaw<8g/L was set as the positive linit,100% of CVA and BA patients showed bronchial hnyrmsponsiveness(BHR), the average positive MCH concentration being about 1.0 g/L. 5 cases with COPD (13.5%) also showed BHR, but the averag MCH concentration was 5.24g/L. (3)If PC35sGaw<4g/L was set as the positive limit for the diagnosis of CVA,the diagnosis of CVA, the sensitivity was 96.7%, specificity 97.3%, confidence limit 99%. (4) A equation for PC35sGaw was deduced,and its calculation values showed the same results with the ones from diagrammatization.Conclusions sGaw is a sensitive index for the measurement of the measurement of bronchial responsiveness,and it is useful in the differentiation of CVA from COPD. It is suggested that PC35sGaw<8g/L be regarded as bronchial hyperresponsiveness, and PC35sGaw<4g/L as candidate for CVA.