Worth H
Respiration. 1975;32(6):436-44. doi: 10.1159/000193676.
In order to study the role of diffusion limitation in alveolar space (stratification) for pulmonary gas exchange function, pulmonary diffusing capacity for CO (Dco) was comparatively measured during breathing of room air and of gas mixtures in which N2 of room air was replaced by He or Ar. Measurements in 15 healthy humans using the single breath method yielded the following mean (+/-SE) values: room air, 22.1+/-1.7; He, 25.1+/-1.3; Ar, 17.4+/-1.0 ml-min-1-Torr-1. The clear negative correlation between Dco and the molecular weight of the gases used is most easily explained on the basis of an airway diffusion resistance limiting CO transfer. For room air breathing this resistance is estimated at about 10% of the total resistance to CO uptake (1/Dco). The alveolar exchange of O2 and CO2 is expected to be affected by the diffusional resistance in airways, particularly at high metabolic levels.
为研究肺泡空间（分层）中扩散限制对肺气体交换功能的作用，在吸入室内空气以及用氦气或氩气替代室内空气中氮气的混合气体时，对一氧化碳肺扩散容量（Dco）进行了对比测量。采用单次呼吸法对15名健康人进行测量，得到以下平均（±标准误）值：室内空气，22.1±1.7；氦气，25.1±1.3；氩气，17.4±1.0 ml·min⁻¹·Torr⁻¹。基于限制一氧化碳传递的气道扩散阻力，最容易解释Dco与所用气体分子量之间明显的负相关关系。对于吸入室内空气，该阻力估计约占一氧化碳摄取总阻力（1/Dco）的10%。预计气道中的扩散阻力会影响氧气和二氧化碳的肺泡交换，尤其是在高代谢水平时。
