Miserocchi G, Negrini D, Pistolesi M, Bellina C R, Gilardi M C, Bettinardi V, Rossitto F
Istituto di Fisiologia Umana I, Università degli Studi, Milano, Italy.
J Appl Physiol (1985). 1988 Feb;64(2):577-84. doi: 10.1152/jappl.1988.64.2.577.
We studied the vertical movement of 2 mg technetium-labeled albumin injected intrapleurally in 0.5 ml saline (15% of pleural liquid volume) in eight spontaneously breathing anesthetized dogs subject to a sudden change in posture (prone to supine or vice versa). The albumin movements were evaluated through a large field gamma camera placed laterally to the animal and detecting total (AT) and regional activities from two superimposed equal areas (At and Ab, top and bottom, respectively). The At/Ab ratio decreased from 2.1 to 1.3 in four animals up to 20 min from the change in posture and from 0.9 to 0.5 in four more animals studied from 50 to 90 min from turning maneuver. The rate of change in At and Ab was similar in the two groups of animals and unaffected by the acquisition posture. AT decreased by 7.7 and 3.5% for the two groups, respectively, reflecting albumin clearance from the pleural space. The opposite time course of regional activities and the independence of their rate of change of the At/Ab ratio and of the animal posture suggest a top-to-bottom albumin transfer occurring through a bulk flow of liquid estimated at 0.006 ml.kg-1.h-1. The data are consistent with a measured vertical pleural liquid pressure gradient that does not reflect a hydrostatic condition.
我们研究了在8只自主呼吸的麻醉犬中，将2毫克锝标记的白蛋白以0.5毫升生理盐水（占胸腔液体体积的15%）经胸膜腔内注射后，在姿势突然改变（俯卧位变为仰卧位或反之）时的垂直移动情况。通过放置在动物侧面的大视野伽马相机评估白蛋白的移动情况，该相机可检测来自两个叠加的相等区域（分别为顶部的At和底部的Ab）的总活性（AT）和区域活性。在姿势改变后的20分钟内，4只动物的At/Ab比值从2.1降至1.3；在翻身操作后的50至90分钟内研究的另外4只动物中，该比值从0.9降至0.5。两组动物中At和Ab的变化率相似，且不受采集姿势的影响。两组的AT分别下降了7.7%和3.5%，这反映了白蛋白从胸腔间隙的清除。区域活性的相反时间进程以及它们的变化率与At/Ab比值和动物姿势的独立性表明，白蛋白通过估计为0.006毫升·千克⁻¹·小时⁻¹的液体总体流动发生自上而下的转移。这些数据与测得的垂直胸腔液体压力梯度一致，该梯度并不反映静水压力情况。
