Drake R, Gaar K A, Taylor A E
Am J Physiol. 1978 Mar;234(3):H266-74. doi: 10.1152/ajpheart.1978.234.3.H266.
Filtration characteristics of the exchange vessels in isolated dog lung were studied by calculating the volume conductance (LP,C) with use of different components of the weight-gain curve following changes in capillary pressure. In one series of lungs, capillary pressure was elevated to levels that produced alveolar edema (29.4 +/- 5.3 (mean +/- SD) mmHg), and total alveolar capillary membrane conductances (LP,T) were calculated using different components of the accumulated weight-gain measurements. These conductance values are similar to those found in the literature for studies in which alveolar edema developed and LP,T was calculated using wet-to-dry weight ratios as a measure of filtered volume. In another series of lungs, capillary pressure was altered by only 5.8 +/- 2.5 mmHg, and LP,C was calculated by estimating the initial filtration rate by an extrapolation method LP,C calculated by use of the extrapolation method (0.71 X 10(-11) cm3/dyn-s) was larger than the LP,T reported in the literature, because LP,T is an estimate of the conductance of the alveolar plus the capillary membrane. Also, for the most calculations of LP,T, tissue forces have changed which causes an overestimation of the filtration driving pressure and thus an underestimate of the capillary volume conductance. After estimating both LP,C and LP,T, the maximum volume conductance of the alveolar membrane (LP,a) was calculated to be 0.13 X 10(-11) cm3/dyn-s.
通过在毛细血管压力变化后利用体重增加曲线的不同组成部分计算容积传导率（LP,C），研究了离体犬肺中交换血管的滤过特性。在一组肺中，将毛细血管压力升高到产生肺泡水肿的水平（29.4±5.3（均值±标准差）mmHg），并使用累积体重增加测量的不同组成部分计算总肺泡毛细血管膜传导率（LP,T）。这些传导率值与文献中报道的相似，在那些研究中出现了肺泡水肿，并使用湿重与干重之比作为滤过量的指标来计算LP,T。在另一组肺中，仅将毛细血管压力改变5.8±2.5 mmHg，并通过外推法估计初始滤过率来计算LP,C。使用外推法计算得到的LP,C（0.71×10⁻¹¹ cm³/dyn-s）大于文献中报道的LP,T，因为LP,T是肺泡加毛细血管膜传导率的估计值。此外，对于大多数LP,T的计算，组织力发生了变化，这导致对滤过驱动压力的高估，从而低估了毛细血管容积传导率。在估计了LP,C和LP,T之后，计算得到肺泡膜的最大容积传导率（LP,a）为0.13×10⁻¹¹ cm³/dyn-s。
