University Hospital Maastricht, Department of Paediatric Pulmonology, Maastricht, The Netherlands.
Pediatr Allergy Immunol. 2010 Feb;21(1 Pt 2):e222-8. doi: 10.1111/j.1399-3038.2009.00874.x.
Measurement of bronchial and alveolar exhaled nitric oxide (NO) levels could be of clinical importance for the treatment of asthma. To discriminate between alveolar and bronchial NO, measurements need to be assessed at various flow rates. To study the feasibility, linearity, and long-term repeatability of NO measurements at four different exhalation flow rates in children with asthma. Twenty-one children with moderate persistent asthma, aged 6-12 yrs, were included in the study. NO was measured according to the ATS/ERS guidelines, using the NIOX analyzer with flow restrictors of 30, 50, 100, and 200 ml/s. Duration of the measurements ranged from 6-10 s, depending on the flow rate. The tests were repeated 3 and 6 months after the first NO measurement. Feasibility of NO measurements at these four flow rates increased from 67% to 91% and 95% at the first, second and third visit, respectively. A significant learning effect was present. Age and lung function indices did not influence success or failure of the tests. At the first measurements occasions, no problems occurred during the NO analysis at a 100 ml/s flow rate. There was a 75-90% success rate when performing the test using flow rates of 30, 50, and 200 ml/s. However, repeating the tests resulted in a 100% success rate. Measurements were not successful if: (i) children ran out of air; (ii) NO concentration exceeded 200 ppb; (iii) the measured NO flow was unstable; and (iv) the NO plateau was not formed. This study showed good feasibility and linearity of NO measurements in asthmatic children of 6 yrs and over at flow rates between 50-200 ml/s. A significant learning effect was present. The long-term reproducibility of alveolar and bronchial NO values during 6 months was moderate.
支气管和肺泡呼出气一氧化氮（NO）水平的测量对于哮喘的治疗可能具有重要的临床意义。为了区分肺泡和支气管 NO，需要在不同的流速下评估测量值。本研究旨在探讨在 4 种不同呼气流速下对哮喘儿童进行 NO 测量的可行性、线性和长期重复性。21 例年龄为 6-12 岁的中度持续性哮喘患儿纳入本研究。根据 ATS/ERS 指南，使用 NIOX 分析仪和 30、50、100 和 200ml/s 的流量限制器进行 NO 测量。根据流速的不同，测量持续时间为 6-10s。第一次 NO 测量后 3 个月和 6 个月重复进行测试。在第一次、第二次和第三次就诊时，四种流速下 NO 测量的可行性从 67%增加到 91%和 95%。存在明显的学习效应。年龄和肺功能指标不影响测试的成功或失败。在第一次测量时，在 100ml/s 流速下进行 NO 分析时没有出现问题。使用 30、50 和 200ml/s 流速进行测试的成功率为 75%-90%。然而，重复测试的成功率为 100%。如果出现以下情况，测量将不成功：（i）儿童用尽空气；（ii）NO 浓度超过 200ppb；（iii）测量的 NO 流量不稳定；（iv）未形成 NO 平台。本研究显示，6 岁及以上哮喘儿童在 50-200ml/s 流速下进行 NO 测量具有良好的可行性和线性。存在明显的学习效应。在 6 个月期间，肺泡和支气管 NO 值的长期重复性为中等。
