Conhaim R L, Lai-Fook S J, Eaton A
Department of Preventive Medicine, University of Wisconsin, Madison 53705.
J Appl Physiol (1985). 1989 Jun;66(6):2659-66. doi: 10.1152/jappl.1989.66.6.2659.
In the initial stages of pulmonary edema, liquid accumulates in the lung interstitium and appears as cuffs around pulmonary vessels. To determine the pattern, rate, and magnitude of cuff formation, we inflated sheep lungs to capacity with liquid (inflation pressure 19 cmH2O) for 3-300 min. After freezing the lobes in liquid N2, we measured perivascular cuff size and total perivascular volume in frozen blocks of each lobe and compared the results with previous measurements in dog lungs. Total cuff volume in sheep lungs reached a maximum value of 5% of air space volume, compared with 9% in dog lungs. In sheep lungs 94% of vessels greater than or equal to 0.5 mm diam and 16% of smaller vessels were surrounded by cuffs. In dog lungs these values were 99 and 47%, respectively. The ratio of cuff area to vessel area reached a maximum of 2.3 in sheep lungs and 3.4 in dog lungs. In an electrical analogue model designed to simulate cuff growth, estimated interstitial resistance to liquid flow was 6-15 times higher than similar estimates in dog lungs. These species differences might be the result of differences in the composition of the interstitial gel or to differences in the mechanical linkage between the lung parenchyma and vessel wall.
在肺水肿的初始阶段，液体在肺间质中积聚，并表现为肺血管周围的套袖状。为了确定套袖形成的模式、速率和程度，我们用液体将羊肺充气至容量（充气压力19 cmH₂O），持续3 - 300分钟。在将肺叶在液氮中冷冻后，我们测量了每个肺叶冷冻块中的血管周围套袖大小和血管周围总体积，并将结果与之前在狗肺中的测量结果进行比较。羊肺中的套袖总体积达到气腔体积的最大值5%，而狗肺中为9%。在羊肺中，直径大于或等于0.5毫米的血管中有94%被套袖包围，较小血管中有16%被套袖包围。在狗肺中，这些值分别为99%和47%。套袖面积与血管面积的比值在羊肺中最高达到2.3，在狗肺中为3.4。在一个旨在模拟套袖生长的电模拟模型中，估计的间质对液体流动的阻力比狗肺中的类似估计值高6 - 15倍。这些物种差异可能是间质凝胶组成差异或肺实质与血管壁之间机械连接差异的结果。
