A model for the regulation of cerebral oxygen delivery
A model for the regulation of cerebral oxygen delivery
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DOI：
10.1152/jappl.1998.85.2.554
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发表时间：
1998-08-01
影响因子：
3.3
通讯作者：
Rothman, DL
中科院分区：
文献类型：
--
作者：
Hyder, F;Shulman, RG;Rothman, DL
在假设通过内皮的氧输送与毛细血管血浆Pot成比例的基础上，提出了通过毛细血管床的有效氧扩散率（D）将脑氧利用代谢率（CMRO 2）与脑血流量（CBF）联系起来的模型。在体内的证据的基础上，毛细血管床的氧扩散性能可能会改变毛细血管Po，血细胞比容，和/或血液体积的变化，该模型允许在D的变化与CBF的变化。在模型中选择合适的Ω =（Δ D/D）/（Δ CBF/CBF）的比率确定组织氧输送对灌注的依赖性。Burton和Frank（J. Cereb.血流Metab. 17：64-72，1997）最近提出了当前模型的极限情况，其中Omega = 0。与Burton和Frank模型预测的趋势相反，在当前模型中，当Omega > 0时，CBF和CMRO 2变化之间的比例变得更加线性，并且在氧提取分数的不同基础值下可以存在类似程度的比例。该模型是能够适应CBF和CMRO 2之间的生理数据的大范围内观察到的比例。尽管该模型没有验证CBF和CMRO 2之间任何特定的观察到的比例，但在大鼠和人类的分级麻醉范围内以及对于人类的特定功能激活，通常观察到接近1的（Δ CMRO 2/CMRO 2）/（Δ CBF/CBF）值。该模型的能力，以适应广泛的数据表明，毛细血管床的氧扩散性能，这可以被修改有关灌注，在体内调节脑氧输送中起着重要的作用。
On the basis of the assumption that oxygen delivery across the endothelium is proportional to capillary plasma Pot, a model is presented that Links cerebral metabolic rate of oxygen utilization (CMRO2) to cerebral blood flow (CBF) through an effective diffusivity for oxygen (D) of the capillary bed. On the basis of in vivo evidence that the oxygen diffusivity properties of the capillary bed may be altered by changes in capillary Po,, hematocrit, and/or blood volume, the model allows changes in D with changes in CBF. Choice in the model of the appropriate ratio of Omega = (Delta D/D)/(Delta CBF/CBF) determines the dependence of tissue oxygen delivery on perfusion. Burton and Frank (J. Cereb. Blood Flow. Metab. 17: 64-72, 1997) recently presented a Limiting case of the present model in which Omega = 0. In contrast to the trends predicted by the model of Burton and Frank, in the current model when Omega > 0, the proportionality between changes in CBF and CMRO2 becomes more Linear, and similar degrees of proportionality can exist at different basal values of oxygen extraction fraction. The model is able to fit the observed proportionalities between CBF and CMRO2 for a large range of physiological data. Although the model does not validate any particular observed proportionality between CBF and CMRO2, generally values of (Delta CMRO2/CMRO2)/(Delta CBF/CBF) close to unity have been observed across ranges of graded anesthesia in rats and humans and for particular functional activations in humans. The model's capacity to fit the wide range of data indicates that the oxygen diffusivity properties of the capillary bed, which can be modified in relation to perfusion, play an important role in regulating cerebral oxygen delivery in vivo.