Background The multiple breath nitrogen washout (N2MBW) technique is increasingly used to assess the degree of ventilation inhomogeneity in school-aged children with lung disease. However, reference values for healthy children are currently not available. The aim of this study was to generate reference values for N2MBW outcomes in a cohort of healthy Caucasian school-aged children. Methods N2MBW data from healthy Caucasian school-age children between 6 and 18 years old were collected from four experienced centres. Measurements were performed using an ultrasonic flowmeter (Exhalyzer D, Eco Medics AG, Duernten, Switzerland) and were analysed with commercial software (Spiroware version 3.2.1, Eco Medics AG). Normative values and upper limits of normal (ULN) were generated for lung clearance index (LCI) at 2.5% (LCI2.5%) and at 5% (LCI5%) of the initial nitrogen concentration and for moment ratios (M1/M0 and M2/M0). A prediction equation was generated for functional residual capacity (FRC). Results Analysis used 485 trials from 180 healthy Caucasian children aged from 6 to 18 years old. While LCI increased with age, this increase was negligible (0.04 units·year–1 for LCI2.5%) and therefore fixed ULN were defined for this age group. These limits were 7.91 for LCI2.5%, 5.73 for LCI5%, 1.75 for M1/M0 and 6.15 for M2/M0, respectively. Height and weight were found to be independent predictors of FRC. Conclusion We report reference values for N2MBW outcomes measured on a commercially available ultrasonic flowmeter device (Exhalyzer D, Eco Medics AG) in healthy school-aged children to allow accurate interpretation of ventilation distribution outcomes and FRC in children with lung disease. This study provides reference values for nitrogen multiple breath washout outcomes in healthy Caucasian children from 6 to 18 years old, measured with a commercially available device http://bit.ly/2rsab8v

中文翻译：

---

学龄高加索儿童多次呼吸冲洗结果的规范数据

背景 多次呼吸氮冲洗 (N2MBW) 技术越来越多地用于评估患有肺病的学龄儿童的通气不均匀程度。但是，目前还没有健康儿童的参考值。本研究的目的是为一组健康的高加索学龄儿童提供 N2MBW 结果的参考值。方法 从四个有经验的中心收集来自 6 至 18 岁的健康高加索学龄儿童的 N2MBW 数据。使用超声波流量计（Exhalyzer D，Eco Medics AG，​​Duernten，Switzerland）进行测量，并使用商业软件（Spiroware 版本 3.2.1，Eco Medics AG）进行分析。肺清除指数 (LCI) 的标准值和正常上限 (ULN) 为 2.5% (LCI2.0)。5%) 和 5% (LCI5%) 的初始氮浓度和力矩比（M1/M0 和 M2/M0）。为功能剩余容量（FRC）生成了一个预测方程。结果分析使用了来自 180 名 6 至 18 岁健康高加索儿童的 485 项试验。虽然 LCI 随着年龄的增长而增加，但这种增加可以忽略不计（LCI2.5% 为 0.04 个单位·年–1），因此为该年龄组定义了固定的 ULN。这些限值分别为 LCI2.5% 的 7.91、LCI5% 的 5.73、M1/M0 的 1.75 和 M2/M0 的 6.15。发现身高和体重是 FRC 的独立预测因子。结论 我们报告了在市售超声波流量计设备（Exhalyzer D，Eco Medics AG) 用于健康学龄儿童，以便准确解释肺部疾病儿童的通气分布结果和 FRC。本研究为 6 至 18 岁健康高加索儿童的氮多次呼吸冲洗结果提供参考值，使用市售设备 http://bit.ly/2rsab8v 测量