Rouhos Annamari, Kainu Annette, Piirilä Päivi, Sarna Seppo, Lindqvist Ari, Karjalainen Jouko, Sovijärvi Anssi R A
Department of Medicine, Division of Respiratory Diseases, Helsinki University Central Hospital, Helsinki, Finland.
Clin Physiol Funct Imaging. 2011 Jan;31(1):26-31. doi: 10.1111/j.1475-097X.2010.00975.x. Epub 2010 Sep 23.
The assessment of the presence of eosinophilic airway inflammation may help in predicting the steroid response in subjects with respiratory symptoms. Unlike patients with asthma, only a subset of patients with chronic obstructive pulmonary disease (COPD) benefits from steroid treatment. Fractional exhaled nitric oxide (FENO) is a useful surrogate marker for eosinophilic airway inflammation, but data on the repeatability of FENO measurements in COPD needed for the assessment of significant change are insufficient. The aim of this study was to assess the short-term repeatability of FENO measurement in subjects with moderate to very severe chronic airway obstruction compared to that in healthy subjects. We studied 20 patients with stable COPD and 20 healthy subjects, and determined FENO (flow rate 50 ml s(-1) ) three times: at baseline, 10 min and 24 h after baseline. Spirometry was performed on the first study day after the FENO measurements. The median FENO concentration in patients with COPD was 15·6 ppb, and in healthy subjects, 15·2 ppb. The coefficient of variation (CoV) for 24-h measurements was 12·4% in COPD patients, and 15·9% in healthy subjects. Among COPD patients with global initiative for chronic obstructive lung disease stage 2 disease, the CoV was 13·7%, and among those with stage 3-4 disease, 10·5%. The findings indicate that the short-term repeatability of FENO measurement in patients with moderate to very severe COPD is equally good as in healthy subjects. A change in FENO exceeding 24% is likely to reflect a minimum measurable change in COPD.
评估嗜酸性气道炎症的存在可能有助于预测有呼吸道症状的受试者对类固醇的反应。与哮喘患者不同，只有一部分慢性阻塞性肺疾病（COPD）患者能从类固醇治疗中获益。呼出一氧化氮分数（FENO）是嗜酸性气道炎症的一个有用替代标志物，但评估显著变化所需的COPD患者FENO测量重复性的数据不足。本研究的目的是评估中度至非常重度慢性气道阻塞患者与健康受试者相比FENO测量的短期重复性。我们研究了20例稳定期COPD患者和20名健康受试者，并在基线、基线后10分钟和24小时测定FENO（流速50 ml s(-1)）三次。在FENO测量后的第一个研究日进行肺功能检查。COPD患者的FENO浓度中位数为15.6 ppb，健康受试者为15.2 ppb。COPD患者24小时测量的变异系数（CoV）为12.4%，健康受试者为15.9%。在慢性阻塞性肺疾病全球倡议2期的COPD患者中，CoV为13.7%，在3-4期患者中为10.5%。研究结果表明中度至非常重度COPD患者FENO测量的短期重复性与健康受试者相当。FENO变化超过24%可能反映了COPD中最小可测量变化。
