Multiple breath washout is a lung function test based on tidal breathing that assesses lung volume and ventilation distribution. The aim of this analysis was to use the Global Lung Function Initiative methodology to develop all-age reference equations for the multiple breath washout indices lung clearance index (LCI) and functional residual capacity (FRC).

Multiple breath washout data from healthy individuals were collated from sites. Data were re-analysed using the latest software versions. Reference equations were derived using the lambda-mu-sigma method using the generalised additive models of location shape and scale programme in R. The impact of equipment type, inert tracer gas and equipment dead space volume on the derived reference ranges were investigated.

Data from 23 sites (n=3647 test occasions) were submitted. Reference equations were derived from 1579 unique observations from participants between the ages of 2 and 81 years. Equipment type, inert tracer gas and equipment dead space volume did not significantly affect the prediction equations for either LCI or FRC. Reference equations for LCI include age as the only predictor, whereas sex-specific reference equations for FRC included height and age.

Global Lung Function Initiative reference equations for multiple breath washout variables provide a standard for reporting and interpretation of LCI and FRC.

多次呼吸冲洗是一种基于潮汐呼吸的肺功能测试，用于评估肺容量和通气分布。该分析的目的是使用全球肺功能倡议方法为多个呼吸清除指数、肺清除率指数 （LCI） 和功能残气量 （FRC） 开发全年龄参考方程。

从站点整理来自健康个体的多次呼吸冲洗数据。使用最新的软件版本重新分析数据。参考方程是使用 lambda-mu-sigma 方法使用 R 中位置形状和比例程序的广义加法模型得出的。研究了设备类型、惰性示踪气体和设备死区体积对得出的参考范围的影响。

提交了来自 23 个站点 （n=3647 个测试场合） 的数据。参考方程式源自 1579 名年龄在 2 至 81 岁之间的参与者的独特观察结果。设备类型、惰性示踪气体和设备死腔体积对 LCI 或 FRC 的预测方程没有显著影响。LCI 的参考方程将年龄作为唯一的预测因子，而 FRC 的性别特异性参考方程包括身高和年龄。

多个呼吸冲洗变量的全球肺功能倡议参考方程为 LCI 和 FRC 的报告和解释提供了标准。