Background: Fractional exhaled nitric oxide (FENO) concentration reliably reflects central airway inflammation, but it is not sensitive to changes in the NO dynamics in the lung periphery. By measuring FENO at several different flow rates one can estimate alveolar NO concentration (C_ANO), bronchial NO flux (J_awNO), bronchial wall NO concentration (C_awNO) and the bronchial diffusivity of NO (D_awNO).

Objective: We aimed to describe the current knowledge and clinical relevance of NO parameters in different pulmonary diseases.

Methods: We conducted a systematic literature search to identify publications reporting NO parameters in subjects with pulmonary or systemic diseases affecting the respiratory tract. A narrative review was created for those with clinical relevance.

Results: Estimation of pulmonary NO parameters allows for differentiation between central and peripheral inflammation and a more precise analysis of central airway NO output. C_ANO seems to be a promising marker of parenchymal inflammation in interstitial lung diseases and also a marker of tissue damage and altered gas diffusion in chronic obstructive pulmonary disease and systemic diseases affecting the lung. In asthma, C_ANO can detect small airway involvement left undetected by ordinary FENO measurement. Additionally, C_awNO and D_awNO can be used in asthma to assess if FENO is increased due to enhanced inflammatory activity (increased C_awNO) or tissue changes related to bronchial remodelling (altered D_awNO).

Conclusion: NO parameters may be useful for diagnosis, prediction of disease progression and prediction of treatment responses in different parenchymal lung and airway diseases. Formal trials to test the added clinical value of NO parameters are needed.

背景：呼出气一氧化氮（FENO）的分数确实反映了中央气道炎症，但对肺周围NO动力学的变化不敏感。通过测量几种不同流速下的FENO，可以估算肺泡NO浓度（C _A NO），支气管NO流量（J _aw NO），支气管壁NO浓度（C _aw NO）和NO的支气管扩散率（D _aw NO）。

目的：我们旨在描述不同肺疾病中一氧化氮参数的最新知识和临床意义。

方法：我们进行了系统的文献检索，以鉴定报告患有影响呼吸道的肺部或全身性疾病的受试者无参数的出版物。为那些具有临床意义的人创建了叙述性评论。

结果：肺NO参数的估计可区分中枢和周围炎症，并更精确地分析中枢气道NO的输出。Ç_甲NO似乎是实质炎症在间质性肺病有希望的标记，并且还组织损伤，慢性阻塞性肺疾病和影响肺全身性疾病改变的气体扩散的标记物。在哮喘中，C _A NO可以检测出普通FENO测量未发现的小气道受累。此外，C _aw NO和D _aw NO可用于哮喘，以评估FENO是否由于炎症活动增强（C _aw NO增加）或与支气管重塑相关的组织改变而增加（D改变）。_糟糕）。

结论：NO参数可能对不同的实质性肺和气道疾病的诊断，疾病进展预测和治疗反应预测有用。需要进行正式试验来测试NO参数的附加临床价值。