Tsang J Y, Baile E M, Hogg J C
J Appl Physiol (1985). 1986 Feb;60(2):449-57. doi: 10.1152/jappl.1986.60.2.449.
We studied the effect of edema on the regional distribution of pulmonary blood flow in 12 anesthetized dogs. Two were controls, six had low-pressure pulmonary edema, and four had high-pressure pulmonary edema. All were ventilated with 100% O2. The physiological shunt fraction (Qs/QT), as an indicator of the degree of venous admixture, was determined by measuring the arterial and venous blood gases and the hemoglobin at different times during the experiment. Cardiac output (QT) was modestly increased by opening the femoral arteriovenous shunts. The initial regional blood flow (Qi) and final regional blood flow (Qf) were marked before and after the shunts were opened, using two differently labeled macroaggregates. The dogs were then killed, and the lungs were removed and sampled completely so that Qi and Qf and the amount of regional extravascular lung water (Wdl) in each regional sample could be measured (sample size: wet wt = 5.9 +/- 2.9 g, n = 833; Wdl ranged from 5.15 +/- 1.18 to 14.42 +/- 2.34 g). The data show that QS/QT increased as QT increased in the three conditions studied. However, there was no correlation between Wdl and Qi, Qf, or the relative change in regional blood flow. The data also show that gravity affects regional blood flow more than it affects regional edema. We conclude that the increased Qs/QT seen with increased pulmonary blood flow cannot be explained by a preferential increase of blood flow to the more edematous regions.
我们研究了水肿对12只麻醉犬肺血流区域分布的影响。2只为对照组，6只患有低压性肺水肿，4只患有高压性肺水肿。所有犬均用100%氧气通气。作为静脉血混合程度指标的生理分流分数（Qs/QT），通过在实验过程中的不同时间测量动脉和静脉血气及血红蛋白来确定。通过开放股动静脉分流适度增加心输出量（QT）。在开放分流前后，使用两种不同标记的大聚合体标记初始区域血流（Qi）和最终区域血流（Qf）。然后处死犬，取出肺并进行完整取样，以便测量每个区域样本中的Qi、Qf和区域血管外肺水（Wdl）量（样本大小：湿重 = 5.9 ± 2.9 g，n = 833；Wdl范围为5.15 ± 1.18至14.42 ± 2.34 g）。数据显示，在所研究的三种情况下，QS/QT随QT增加而增加。然而，Wdl与Qi、Qf或区域血流的相对变化之间无相关性。数据还显示，重力对区域血流的影响大于对区域水肿的影响。我们得出结论，肺血流增加时所见的Qs/QT增加不能用血流优先增加至水肿更严重区域来解释。
