Department of Paediatric Pulmonology & Allergology, Children's Hospital, St. Gallen, Switzerland.
PLoS One. 2013;8(1):e54521. doi: 10.1371/journal.pone.0054521. Epub 2013 Jan 18.
Fractional exhaled nitric oxide (FENO), a non-invasive marker of eosinophilic airway inflammation, is increasingly used for diagnostic and therapeutic decisions in adult and paediatric asthma. Standardized guidelines for the measurement of FENO recommend performing FENO measurements before rather than after bronchial provocation tests.
To investigate whether FENO levels decrease after a Mannitol dry powder (MDP) challenge in a clinical setting, and whether the extent of the decrease is influenced by number of MDP manoeuvres, baseline FENO, atopy and doctor diagnosed asthma.
Children aged 6-16 years, referred for possible reactive airway disease to a respiratory outpatient clinic, performed an MDP challenge (Aridol®, Pharmaxis, Australia). FENO was measured in doublets immediately before and after the challenge test using the portable NIOX MINO® device (Aerocrine, Stockholm, Sweden). We analysed the data using Kruskal-Wallis rank tests, Wilcoxon signed rank tests and multivariable linear regressions.
One hundred and seven children completed both tests (mean±SD age 11.5±2.8 years). Overall, median (interquartile range) FENO decreased slightly by -2.5 ppb (-7.0, -0.5), from 18.5 ppb (10.5, 45.5) before the MDP challenge to 16.5 ppb thereafter (8.5, 40.5; p<0.001). In all participants, the change in FENO was smaller than one standard deviation of the baseline mean. The % fall in FENO was smaller in children with less MDP manoeuvres (e.g. higher bronchial responsiveness; p = 0.08) but was not influenced by levels of baseline FENO (p = 0.68), atopy (p = 0.84) or doctor diagnosed asthma (p = 0.93).
MDP challenge test influences FENO values but differences are small and clinically barely relevant.
呼出气一氧化氮（FENO）分数，一种非侵袭性的气道嗜酸性粒细胞炎症标志物，越来越多地用于成人和儿童哮喘的诊断和治疗决策。用于测量 FENO 的标准化指南建议在进行支气管激发试验之前而不是之后进行 FENO 测量。
研究在临床环境中，甘露糖醇干粉（MDP）激发试验后 FENO 是否会降低，以及降低的程度是否受 MDP 操作次数、基线 FENO、特应性和医生诊断的哮喘的影响。
年龄在 6-16 岁的儿童，因可能患有反应性气道疾病而被转介到呼吸门诊，进行 MDP 激发试验（Aridol®，Pharmaxis，澳大利亚）。使用便携式 NIOX MINO®设备（Aerocrine，斯德哥尔摩，瑞典）在激发试验前后立即进行 FENO 的双份测量。我们使用 Kruskal-Wallis 秩检验、Wilcoxon 符号秩检验和多变量线性回归分析数据。
107 名儿童完成了两项测试（平均年龄±标准差为 11.5±2.8 岁）。总体而言，中位（四分位间距）FENO 略有下降，从 MDP 激发前的 18.5 ppb（10.5，45.5）下降至 16.5 ppb（8.5，40.5）（p<0.001）。在所有参与者中，FENO 的变化小于基线平均值的一个标准差。FENO 下降的百分比在进行较少 MDP 操作的儿童中较小（例如支气管高反应性；p = 0.08），但不受基线 FENO 水平（p = 0.68）、特应性（p = 0.84）或医生诊断的哮喘（p = 0.93）的影响。
MDP 激发试验会影响 FENO 值，但差异较小，临床上几乎无相关性。
