Gravity is an important but secondary determinant of regional pulmonary blood flow in upright primates
Gravity is an important but secondary determinant of regional pulmonary blood flow in upright primates
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DOI：
10.1152/jappl.1999.86.2.623
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发表时间：
1999-02-01
影响因子：
3.3
通讯作者：
Hlastala, MP
中科院分区：
文献类型：
--
作者：
Glenny, RW;Bernard, S;Hlastala, MP
导致肺血流重力模型的原始研究和显示重力无关灌注的当代研究在最近使用实验室动物而不是人类中有所不同。我们探讨了狒狒肺血流的分布，因为它们的解剖结构，血管阻力的系列分布，以及对缺氧的血流动力学反应与人类相似。用氯胺酮麻醉4只狒狒，插管并机械通气。当动物处于仰卧、俯卧、直立（重复）和头朝下（重复）姿势时，静脉内给予不同颜色的荧光微球。将动物处死，切除其肺，干燥，并切成类似于2 cm（3）的碎片，并记录每个碎片的空间坐标。从每一片的荧光信号确定每个姿势的局部血流。灌注异质性在直立姿势时最大，在俯卧时最小。使用多元逐步回归，我们估计，7%，5%和25%的灌注异质性是由于重力在仰卧，俯卧和直立姿势，分别。虽然重要，重力不是直立灵长类动物肺灌注异质性的主要决定因素。由于解剖学上的相似性，人类可能也是如此。
Original studies leading to the gravitational model of pulmonary blood flow and contemporary studies showing gravity-independent perfusion differ in the recent use of laboratory animals instead of humans. We explored the distribution of pulmonary blood flow in baboons because their anatomy, serial distribution of vascular resistances, and hemodynamic responses to hypoxia are similar to those of humans. Four baboons were anesthetized with ketamine, intubated, and mechanically ventilated. Different colors of fluorescent microspheres were given intravenously while the animals were in the supine, prone, upright (repeated), and head-down (repeated) postures. The animals were killed, and their lungs were excised, dried, and diced into similar to 2-cm(3) pieces with the spatial coordinates recorded for each piece. Regional blood flow was determined for each posture from the fluorescent signals of each piece. Perfusion heterogeneity was greatest in the upright posture and least when prone. Using multiple-stepwise regression, we estimate that 7, 5, and 25% of perfusion heterogeneity is due to gravity in the supine, prone, and upright postures, respectively. Although important, gravity is not the predominant determinant of pulmonary perfusion heterogeneity in upright primates. Because of anatomic similarities, the same may be true for humans.