Geiser J, Chinet A, Haab P
Respir Physiol. 1979 May;37(1):31-44. doi: 10.1016/0034-5687(79)90090-2.
Steady-state pulmonary gas exchange has been measured in hypoxia in 33 mongrel dogs with the aim of comparing DLO2 estimates obtained with three procedures differing by the models assumed for functional inhomogeneity. In the first procedure the lung was assumed to be homogeneous and the corresponding DLO2 estimate was 15 mumol . min-1. Torr-1 . kg-1. In the second procedure, which is the one commonly used in respiratory physiology, alveolar dead space was considered as the unique form of functional inhomogeneity and the corresponding DLO2 estimate was 31 mumol . min-1. Torr-1 . kg-1. In the third procedure, which has been specially worked out for this study, functional inhomogeneity was represented by a log-normal distribution of the VA/Q ratios and the corresponding DLO2 estimate was 50 mumol . min-1 . Torr-1 . kg-1. The relation between the DLO2 estimates by the second and by the third procedures was found to depend upon the blood pH. This could be explained on the basis of the effects of acidosis on the blood capacitances for O2 and for CO2. Analysis suggests that in hypoxia where normally the O2 capacitance is about half the CO2 one, the third procedure yields DLO2 estimates about twice as large as those obtained by the second one.
对33只杂种犬在低氧状态下的稳态肺气体交换进行了测量，目的是比较用三种程序获得的氧弥散量（DLO2）估计值，这三种程序因对功能不均匀性所假设的模型不同而有所差异。在第一种程序中，假定肺是均匀的，相应的DLO2估计值为15 μmol·min⁻¹·Torr⁻¹·kg⁻¹。在第二种程序中，即呼吸生理学中常用的程序，肺泡死腔被视为功能不均匀性的唯一形式，相应的DLO2估计值为31 μmol·min⁻¹·Torr⁻¹·kg⁻¹。在第三种程序中，该程序是专门为这项研究设计的，功能不均匀性由通气/血流比值（VA/Q）的对数正态分布表示，相应的DLO2估计值为50 μmol·min⁻¹·Torr⁻¹·kg⁻¹。发现第二种和第三种程序得到的DLO2估计值之间的关系取决于血液pH值。这可以根据酸中毒对血液中氧气和二氧化碳容量的影响来解释。分析表明，在正常情况下氧气容量约为二氧化碳容量一半的低氧状态下，第三种程序得到的DLO2估计值约为第二种程序的两倍。
