Respiratory Division, University Hospital UZ Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium.
Thorax. 2012 Sep;67(9):789-95. doi: 10.1136/thoraxjnl-2011-201484. Epub 2012 Apr 27.
Small airways function studies in lung disease have used three promising multiple breath washout (MBW) derived indices: indices of ventilation heterogeneity in the acinar (S(acin)) and conductive (S(cond)) lung zones, and the lung clearance index (LCI). Since peripheral lung structure is known to change with age, ventilation heterogeneity is expected to be affected too. However, the age dependence of the MBW indices of ventilation heterogeneity in the normal lung is unknown.
The authors systematically investigated S(acin), S(cond) or LCI as a function of age, testing also the robustness of these relationships across two laboratories.
MBW tests were performed by never-smokers (50% men) in the age range 25-65 years, with data gathered across two laboratories (n=120 and n=60). For comparison with the literature, the phase III slopes from classical single breath washout tests were also acquired in one group (n=120).
All three MBW indices consistently increased with age, representing a steady worsening of ventilation heterogeneity in the age range 25-65. Age explained 7-16% of the variability in S(acin) and S(cond) and 36% of the variability in LCI. There was a small but significant gender difference only for S(acin). Classical single breath washout phase III slopes also showed age dependencies, with gender effects depending on the normalisation method used.
With respect to the clinical response, age is a small but consistent effect that needs to be factored in when using the MBW indices for the detection of small airways abnormality in disease.
在肺部疾病的小气道功能研究中，已经使用了三个有前途的多呼吸冲洗（MBW）衍生指数：腺泡（S（acin））和传导（S（cond））肺区通气异质性的指数，以及肺清除指数（LCI）。由于已知周围肺结构随年龄而变化，通气异质性预计也会受到影响。然而，正常肺的 MBW 通气异质性指数的年龄依赖性尚不清楚。
作者系统地研究了 S（acin）、S（cond）或 LCI 随年龄的变化，还测试了这些关系在两个实验室之间的稳健性。
对年龄在 25-65 岁之间的不吸烟者（50%为男性）进行 MBW 测试，数据来自两个实验室（n=120 和 n=60）。为了与文献进行比较，还在一组（n=120）中获得了经典单呼吸冲洗测试的第三阶段斜率。
所有三个 MBW 指数都随着年龄的增长而持续增加，代表了 25-65 岁之间通气异质性的稳定恶化。年龄解释了 S（acin）和 S（cond）变异性的 7-16%，解释了 LCI 变异性的 36%。仅 S（acin）存在性别差异，但差异较小。经典单呼吸冲洗第三阶段斜率也显示出年龄依赖性，性别效应取决于所使用的归一化方法。
就临床反应而言，年龄是一个微小但一致的影响因素，在使用 MBW 指数检测疾病中小气道异常时需要考虑到这一点。
