Exhaled nitric oxide as a diagnostic test for asthma - Online versus offline techniques and effect of flow rate
Exhaled nitric oxide as a diagnostic test for asthma - Online versus offline techniques and effect of flow rate
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DOI：
10.1164/rccm.2201081
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发表时间：
2002-06-15
影响因子：
24.7
通讯作者：
Israel, E
中科院分区：
文献类型：
--
作者：
Deykin, A;Massaro, AF;Israel, E
测量呼出气一氧化氮（FENO）的分数已被提议作为哮喘气道炎症的非侵入性评估。收集动作期间呼气流速对FENO区分健康受试者和哮喘受试者的能力的影响尚不清楚。我们比较了在线和离线测量FENO在不同的流量。采用脱机采集技术，在50-500 ml/s呼气流速下采集34例哮喘患者（PC 20 <8 mg/ml）和28例健康受试者（PC 20> 10 mg/ml）的FENO。在一个由18名哮喘患者和17名健康受试者组成的亚组中，我们还使用在线方法在多种呼气流速（47-250 ml/s）下测量了FENO。FENO随着呼气流速的增加而降低;在两种技术研究的每个流速下，哮喘受试者的FENO均高于健康受试者（p < 0.001）。用于诊断哮喘的受试者工作特征（ROC）曲线表明FENO是哮喘个体和健康受试者之间的稳健的鉴别（ROC曲线下面积为0.79 +/- 0.06至0.86 +/- 0.06，显著区分的p < 0.0001）。呼气流速和采集技术（在线与离线）均未显著改变这种区分能力（最慢在线方法的ROC曲线下面积= 0.84 +/- 0.07，最快离线方法的ROC曲线下面积= 0.80 +/- 0.07，p = 0.46）。这些数据表明，呼气流速和采集方法的选择可以基于实用性和患者舒适度，而不会影响该测试对哮喘的实用性。
Measurement of the fraction of exhaled nitric oxide (FENO) has been proposed as a noninvasive assessment of asthmatic airway inflammation. The influence of the expiratory flow rate during the collection maneuver on the ability of FENO to discriminate healthy subjects from those with asthma is unknown. We compared online and offline measurement of FENO at different flow rates. FENO was collected with expiratory flows of 50-500 ml/second in 34 patients with asthma (PC20 of less than 8 mg/ml) and 28 healthy subjects (PC20 of more than 10 mg/ml) using offline collection techniques. In a subgroup of 18 individuals with asthma and 17 healthy subjects, we additionally measured FENO at multiple expiratory flow rates (47-250 ml/second) using online methods. FENO fell with an increasing expiratory flow rate; FENO was higher in subjects with asthma as compared with healthy subjects at each flow rate studied with both techniques (p < 0.001). Receiver operating characteristic (ROC) curves for the diagnosis of asthma indicated that FENO is a robust discriminator between individuals with asthma and healthy subjects (area under the ROC curves 0.79 +/- 0.06 to 0.86 +/- 0.06, p for significant discrimination < 0.0001). Neither expiratory flow rate nor collection technique (online versus offline) significantly altered this discriminatory capacity (area under the ROC curves = 0.84 +/- 0.07 with the slowest online method versus 0.80 +/- 0.07 with the fastest offline method, p = 0.46). These data indicate that the choice of expiratory flow rate and collection method can be based on practicality and patient comfort without compromising the utility of this test for asthma.