Effect of airway and left atrial pressures on microvascular and interstitial pressures in adult lungs.
Effect of airway and left atrial pressures on microvascular and interstitial pressures in adult lungs.
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气道和左心房压力对成人肺部微血管和间质压力的影响。
DOI：
10.1152/jappl.1993.74.5.2112
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Kaplowitz,MR
中科院分区：
文献类型：
--
作者：
Fike,CD;Kaplowitz,MR
本研究的目的是确定肺充气和左心房压力对成年兔离体灌注肺中 20 至 80 微米直径小动脉和小静脉流体通量的静水压力梯度的影响。我们使用微穿刺技术，在 5 和 15 cmH2O 的恒定气道压力下测量微血管或间质压力，并将左心房压力调整至高于（区域 3 条件）或低于（区域 2 条件）气道压力。只有在充气至较高气道压力的肺部中，左心房压力降低至气道压力以下才会导致小静脉压力随之降低。这表明，随着充气从 5 cmH2O 到 15 cmH2O，区域 2 中的流量限制位置从直径 > 80 微米的小静脉转移到直径 <20 微米的血管。当肺部处于 3 区条件下时，与较低气道压力相比，较高气道压力下的经小动脉和经静脉梯度（微血管间质压力）更大。相反，在 2 区条件下，在两种充气压力下进行比较时，经小动脉和经小静脉的梯度沿相反方向变化。抵消跨微血管梯度的变化使得难以预测 2 区条件下肺膨胀对液体过滤的影响。当充气期间维持 3 区条件时，水肿形成的趋势会增加。
The purpose of this study was to determine the effect of lung inflation and left atrial pressure on the hydrostatic pressure gradient for fluid flux across 20- to 80-microns-diam arterioles and venules in isolated perfused lungs of adult rabbits. We used the micropuncture technique and measured microvascular or interstitial pressures at constant airway pressures of 5 and 15 cmH2O with left atrial pressure adjusted above (zone 3 conditions) or below (zone 2 conditions) airway pressure. Only in lungs inflated to the higher airway pressure did a reduction in left atrial pressure below airway pressure result in concomitant reductions in venular pressure. This suggests that the site of flow limitation in zone 2 shifted from venules > 80 microns diam toward vessels <20 microns diam with inflation from 5 to 15 cmH2O. With the lungs under zone 3 conditions, both transarteriolar and transvenular gradients (microvascular-interstitial pressures) were greater at the higher compared with the lower airway pressure. In contrast, transarteriolar and transvenular gradients changed in opposite directions when compared at the two inflation pressures under zone 2 conditions. Counteracting changes in transmicrovascular gradients make it difficult to predict the effect on fluid filtration from lung inflation under zone 2 conditions. When zone 3 conditions are maintained during inflation, the tendency for edema formation should increase.