Hauge A, Bo G, Aarseth P
Acta Anaesthesiol Scand. 1977;21(5):413-22. doi: 10.1111/j.1399-6576.1977.tb01241.x.
The effect on lung compliance of changes in intra- and extravascular volumes has been studied. Such changes were induced by inflation and deflation of a balloon placed in the left atrium in open-chest cats. Blood constituents were labeled with isotopes, and tissue water content was found from the wet/dry labeled with isotopes, and tissue water content was found from the wet/dry weight ratio. When left atrial pressure (PLA) was elevated to a value not exceeding 32 mmHg (4.256 kPa), there was only a minute increase in tissue water volume, and we observed a reversible reduction in lung compliance related to the rise in lung blood volume. At higher PLA, a rapid rise occurred in extravascular fluid volume, with evidence of alveolar flooding. Earlier experiemtns have shown that, in isolated perfused lung, a situation of slow, steady increase in interstitial fluid can be created. This does not seem to be the case with lungs in situ: once the lymphatic drainage is unable to cope with transvascular fluid flow, an unstable situation is created. This rapidly leads to alveolar flooding and a fall in compliance in addition to that caused by a rise in blood volume. From our fluid and pressure determinations, we calculated a filtration coefficient (Kf) of 0.45 ml/100 g wet lung X cmH2O X h. This is within the range reported for sheep lungs. Observation of dynamic lung compliance cannot be used for detection of interstitial fluid accumulation. It appears, however, that in contrast to isolated lungs, this phase of edema-formation rapidly leads to alveolar flooding.
研究了血管内和血管外容量变化对肺顺应性的影响。在开胸猫的左心房内放置一个气球，通过气球的充气和放气来引起这种变化。用同位素标记血液成分，并根据湿重/干重比来测定组织含水量。当左心房压力（PLA）升高到不超过32 mmHg（4.256 kPa）时，组织含水量仅有微小增加，并且我们观察到与肺血容量增加相关的肺顺应性可逆性降低。在更高的PLA时，血管外液体积迅速增加，有肺泡水肿的迹象。早期实验表明，在离体灌注肺中，可以造成间质液缓慢、稳定增加的情况。但在原位肺中似乎并非如此：一旦淋巴引流无法应对跨血管的液体流动，就会产生不稳定状态。这除了导致因血容量增加引起的顺应性下降外，还会迅速导致肺泡水肿和顺应性降低。根据我们对液体和压力的测定，我们计算出滤过系数（Kf）为0.45 ml/100 g湿肺×cmH2O×h。这在报道的绵羊肺的范围内。动态肺顺应性的观察不能用于检测间质液的积聚。然而，与离体肺相比，似乎这个水肿形成阶段会迅速导致肺泡水肿。
