de Winter-de Groot K M, van der Ent C K
Department of Paediatric Respiratory Medicine, University Medical Centre, Utrecht, The Netherlands.
Eur J Clin Invest. 2009 Jan;39(1):72-7. doi: 10.1111/j.1365-2362.2008.02064.x.
Specific guidelines are developed for the measurement of bronchial FE(NO), however, nasal nitric oxide (nNO) measurement is not standardised yet, resulting in divergent nNO values. This study compares six different sampling methods for nNO as described in the literature, to analyse their outcome and short term and long term reproducibility.
nNO concentrations were measured in 38 healthy subjects. Each subject performed nNO measurements during tidal breathing (nNO-TB), single breath quiet exhalations (nNO-QE), QE with oral exhalation against a resistance (nNO-QE + R), breath holding (nNO-BH) and during single-breath humming exhalations at 128 and 440 Hz (nNO-HE(128) and nNO-HE(440), respectively). To assess short term and long term reproducibility all manoeuvres were repeated after one and 24 h.
Lowest values were found during quiet exhalation (mean nNO-QE was 364 p.p.b., SEM 27). Methods in which there is turbulence of nasal flow (as in TB, HE(128) and HE(440)) result in higher nNO levels. Highest values were found in methods with decreased nasal flow [when there is no nasal flow as in BH or when the velum is closed as in QE + R: mean nNO 763 p.p.b. (SEM 61)]. NNO during humming at 440 Hz was significantly higher than at 128 Hz (P < 0.01). The within-subject coefficient of variation of repeated measurements was lowest during humming and breath holding, 3.4 and 3.8%, respectively. Concerning short term and long term reproducibility, best agreement is reached with humming and second best with breath holding.
Different methods result in different levels and reproducibility of nNO. In regard to this, methods of humming and breath holding are recommended for standardised measurement of nasal NO.
针对支气管呼出一氧化氮（FE(NO)）的测量已制定了具体指南，然而，鼻一氧化氮（nNO）的测量尚未标准化，导致nNO值存在差异。本研究比较了文献中描述的六种不同的nNO采样方法，以分析其结果以及短期和长期的可重复性。
对38名健康受试者测量nNO浓度。每位受试者在潮气呼吸（nNO-TB）、单次平静呼气（nNO-QE）、对抗阻力进行口腔呼气的QE（nNO-QE + R）、屏气（nNO-BH）以及在128 Hz和440 Hz进行单次哼唱呼气时（分别为nNO-HE(128)和nNO-HE(440)）测量nNO。为评估短期和长期可重复性，所有操作在1小时和24小时后重复进行。
在平静呼气时发现nNO值最低（平均nNO-QE为364 ppb，标准误27）。存在鼻气流湍流的方法（如在TB、HE(128)和HE(440)中）会导致更高的nNO水平。在鼻气流减少的方法中发现nNO值最高[如在BH中无鼻气流时或在QE + R中软腭关闭时：平均nNO 763 ppb（标准误61）]。440 Hz哼唱时的nNO显著高于128 Hz时（P < 0.01）。重复测量的受试者内变异系数在哼唱和屏气时最低，分别为3.4%和3.8%。关于短期和长期可重复性，哼唱时一致性最佳，屏气时次之。
不同方法导致nNO的水平和可重复性不同。就此而言，推荐哼唱和屏气方法用于鼻一氧化氮的标准化测量。
