呼出气一氧化氮预测慢性咳嗽患儿气道高反应性临床价值研究

Clinical value of expired nitric oxide level in predicting bronchial hyperreactivity in children with chronic cough

目的分析慢性咳嗽患儿呼出气一氧化氮（FeNO）水平与支气管激发试验结果的相关性,探讨能否应用FeNO预测慢性咳嗽患儿气道高反应性。方法对于中国医科大学附属盛京医院小儿呼吸内科门诊就诊的276例慢性咳嗽患儿,进行Fe NO、肺功能和乙酰甲胆碱为激发剂的支气管激发试验检查。结果支气管激发试验阳性组患儿122例,阴性组154例,阳性组的Fe NO值为20.0×10^-9（14.0×10^-9-37.51×10^-9）,阴性组的Fe NO值为16.0×10^-9（12.0×10^-9-21.0×10^-9）,两者间差异存在统计学意义（P=0.000）;为明确Fe NO对于支气管激发试验结果是否存在判别作用,绘制受试者工作特征曲线（ROC）,FeNO预测气道激发试验结果的最佳阈值为31.5×10^-9,相对应的敏感性为28.7%,特异性为97.4%,阳性预测值89.5%,阴性预测值63.0%;FeNO与FEV1%下降20%时吸入的乙酰甲胆碱累积剂量（PD20-FEV1）之间不存在剂量相关性。结论慢性咳嗽患儿的FeNO值对于气道高反应性有一定的预测作用。当FeNO〉31.5×10^-9时预测支气管激发试验阳性的准确性较高,提示患儿存在气道高反应性;当FeNO〈31.5×10^-9时,不能对支气管激发试验阳性或阴性做出预测,须进一步行支气管激发试验以判断气道的反应性。

ObjectiveTo evaluate the role of expired nitric oxide（FeNO）level in chronic cough children to predictbronchial hyperresponsiveness by analyzing the correlation between fraction of expired nitric oxide and bronchial provo-cation test.MethodsWe conducted a study on 276 chronic cough children to measure their FeNO concentration,andwe performed spirometry and methacholine provocation tests.ResultsAccording to the results of bronchial provocationtests,there were 122 cases positive（positive group）and 154 negative cases（negative group）. The positive group had asignificantly higher FeNO than negative group（20.0 × 10^-9vs. 16.0 × 10^-9,P=0.000）. By constructing ROC curve,wefound that FeNO cut-off value of 31. 5 ppb was able to identify bronchial hyperresponsiveness with high specificity（97.4%）and positive predictive value（89.5%）but low sensitivity（28.7%）and negative predictive value（63.0%）.There was no relationship between the methacholine provocative dose causing a 20% fall in FEV1（PD20- FEV1）andthe level of FeNO.ConclusionFeNO measurement has some predictable effects for bronchial hyperreactivity in chil-dren with chronic cough. The level of FeNO〉31.5×10^-9has high predictive value in chronic cough children with bronchi-al hyperreactivity. However,FeNO〈31.5×10^-9does not rule out bronchial hyperreactivity and should call for a bronchial provocation test.