Institute of Medicine, Chung-Shan Medical University, Taichung, Taiwan, ROC.
J Chin Med Assoc. 2013 Jan;76(1):15-9. doi: 10.1016/j.jcma.2012.08.010. Epub 2012 Nov 22.
Chronic cough related to eosinophilic inflammation has become an important cause of cough in recent years. Although fractional exhaled nitrogen oxide (FeNO) measurement is an important monitoring tool, its lack of reference level may limit its usefulness. This study aimed to determine the optimal FeNO level to guide inhaled corticosteroid (ICS) management in patients with chronic cough.
This retrospective study reviewed the medical records of patients with chronic cough for more than 8 weeks. Based on the selection criteria, data were recalculated to determine the optimal cut-off value of FeNO for initiating ICS treatment in such patients.
The medical records of 81 eligible patients were reviewed. Cough improved completely in 38 (Group A) of 44 patients who were treated with ICS but not in the other six patients (Group B). In the 37 patients without ICS treatment, cough improved in 32 (Group C) by specific treatment aimed at the possible causes of the cough, whereas the remaining five (Group D) had persistent cough. The patients were further subdivided into Category 1 (all patients in Group A) and Category 2 (all patients in Groups B and C). Receiver operating characteristic analysis showed that an FeNO of 33.9 ppb was the best cut-off value for using ICS (sensitivity 94.7%, specificity 76.3%) in patients with chronic cough. In fourteen of 15 patients with bronchial hyperresponsiveness (BHR) or borderline BHR, the FeNO values were equal or higher than 33.9 ppb. Obstructive ventilatory impairment was only seen in two patients.
Using FeNO measurement as a rapid, noninvasive diagnostic tool for patients with chronic cough, ICS can be prescribed if the FeNO is 33.9 ppb or more.
近年来，与嗜酸性粒细胞炎症相关的慢性咳嗽已成为咳嗽的一个重要病因。虽然呼出气一氧化氮（FeNO）测定是一种重要的监测工具，但由于缺乏参考水平，其应用可能受到限制。本研究旨在确定最佳 FeNO 水平，以指导慢性咳嗽患者吸入皮质类固醇（ICS）的管理。
本回顾性研究回顾了慢性咳嗽超过 8 周的患者的病历。根据入选标准，重新计算数据以确定此类患者开始 ICS 治疗时 FeNO 的最佳截断值。
共回顾了 81 例符合条件的患者的病历。44 例接受 ICS 治疗的患者中，38 例（A 组）咳嗽完全缓解，而其余 6 例（B 组）未缓解。在未接受 ICS 治疗的 37 例患者中，32 例（C 组）通过针对咳嗽可能病因的特异性治疗咳嗽缓解，而其余 5 例（D 组）持续咳嗽。患者进一步分为 1 类（A 组所有患者）和 2 类（B 组和 C 组所有患者）。受试者工作特征分析显示，33.9 ppb 的 FeNO 是慢性咳嗽患者使用 ICS 的最佳截断值（敏感性 94.7%，特异性 76.3%）。在 15 例支气管高反应性（BHR）或边缘性 BHR 的患者中，有 14 例的 FeNO 值等于或高于 33.9 ppb。仅在 2 例患者中观察到阻塞性通气功能障碍。
使用 FeNO 测量作为慢性咳嗽患者的快速、无创诊断工具，如果 FeNO 值为 33.9 ppb 或更高，可开具 ICS 处方。
