Glenny R W, Robertson H T, Hlastala M P
Department of Medicine, University of Washington 98195, USA.
J Appl Physiol (1985). 2000 Dec;89(6):2263-7. doi: 10.1152/jappl.2000.89.6.2263.
To determine whether vasoregulation is an important cause of pulmonary perfusion heterogeneity, we measured regional blood flow and gas exchange before and after giving prostacyclin (PGI(2)) to baboons. Four animals were anesthetized with ketamine and mechanically ventilated. Fluorescent microspheres were used to mark regional perfusion before and after PGI(2) infusion. The lungs were subsequently excised, dried inflated, and diced into approximately 2-cm(3) pieces (n = 1,208-1,629 per animal) with the spatial coordinates recorded for each piece. Blood flow to each piece was determined for each condition from the fluorescent signals. Blood flow heterogeneity did not change with PGI(2) infusion. Two other measures of spatial blood flow distribution, the fractal dimension and the spatial correlation, did not change with PGI(2) infusion. Alveolar-arterial O(2) differences did not change with PGI(2) infusion. We conclude that, in normal primate lungs during normoxia, vasomotor tone is not a significant cause of perfusion heterogeneity. Despite the heterogeneous distribution of blood flow, active regulation of regional perfusion is not required for efficient gas exchange.
为了确定血管调节是否是肺灌注异质性的重要原因，我们在给狒狒注射前列环素（PGI₂）前后测量了局部血流和气体交换情况。4只动物用氯胺酮麻醉并进行机械通气。在注入PGI₂前后，使用荧光微球标记局部灌注情况。随后切除肺部，干燥充气后切成约2立方厘米的小块（每只动物n = 1208 - 1629块），并记录每块的空间坐标。根据荧光信号确定每种情况下每块的血流情况。注入PGI₂后血流异质性未发生变化。另外两个衡量空间血流分布的指标，分形维数和空间相关性，在注入PGI₂后也未发生变化。肺泡 - 动脉氧分压差在注入PGI₂后也未发生变化。我们得出结论，在正常氧合状态下的正常灵长类动物肺中，血管运动张力不是灌注异质性的重要原因。尽管血流分布不均，但高效气体交换并不需要对局部灌注进行主动调节。
