A model of brain arteriolar oxygen and carbon dioxide transport during anemia.
A model of brain arteriolar oxygen and carbon dioxide transport during anemia.
复制标题
贫血期间脑小动脉氧气和二氧化碳运输的模型。
DOI：
10.1038/jcbfm.1993.109
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Adams,JM
中科院分区：
文献类型：
--
作者：
Schacterle,RS;Ribando,RJ;Adams,JM
现有的实验和理论证据表明，在正常生理条件下，小动脉和组织之间会发生 O2 和 CO2 的毛细血管前扩散。然而，有关贫血期间小动脉气体运输的信息有限。利用脑组织小动脉网络的数学模型，对 35%、25% 和 15% 的贫血血细胞比容进行建模，以确定贫血对交换的影响、平衡组织 O2 和 CO2 张力的变化以及恢复组织氧合所需的血流量增加。我们发现，在最严重的贫血期间，离开网络的血液 Po2 从正常的 66 mm Hg 下降到 48 mm Hg。同时，平衡组织氧张力从 44 毫米汞柱降至 23 毫米汞柱。对于 CO2，15% 血细胞比容时，出口血液 Pco2 为 58 mm Hg，比正常值增加 4 mm Hg，平衡组织 Pco2 从 56 增加到 61 mm Hg。抵消组织供氧量减少的影响所需的血流量从正常值增加分别为 26%、86% 和 222%，血细胞比容分别为 35%、25% 和 15%。我们将模型结果与最近的实验研究进行了比较，这些研究表明 O2 扩散量远高于预测值。我们发现这些实验的 O2 梯度比理论值大三到四倍。
Existing experimental and theoretical evidence suggests that precapillary diffusion of O2and CO2occurs between arterioles and tissue under normal physiologic conditions. However, limited information is available on arteriolar gas transport during anemia. With use of a mathematical model of an arteriolar network in brain tissue, anemic hematocrits of 35, 25, and 15% were modeled to determine the effect of anemia on the exchange, the change in the equilibrium tissue O2and CO2tensions, and the increase in blood flow needed to restore tissue oxygenation. We found that the blood Po2exiting the network fell from 66 mm Hg normally to 48 mm Hg during the severest anemia. Concurrently, the equilibrium tissue O2tensions dropped from 44 to 23 mm Hg. For CO2the exit blood Pco2was 58 mm Hg for a 15% hematocrit, an increase of 4 mm Hg from the normal value, and equilibrium tissue Pco2increased from 56 to 61 mm Hg. Blood flow increases from normal values necessary to offset the effects of the decreased O2delivery to the tissue were 26, 86, and 222%, respectively, for hematocrits of 35, 25, and 15%. We compared our model results with recent experimental studies that have suggested that the amount of O2diffusion is much higher than predicted values. We found that these experimental O2gradients are three to four times larger than theoretical.