Perfusion, diffusion and their heterogeneities limiting blood-tissue O2 transfer in muscle.
Perfusion, diffusion and their heterogeneities limiting blood-tissue O2 transfer in muscle.
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灌注、扩散及其异质性限制了肌肉中血液组织的 O2 转移。
DOI：
10.1046/j.1365-201x.2000.00711.x
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
J. Piiper
中科院分区：
文献类型：
--
作者：
J. Piiper
血流（灌注）和扩散在运动肌肉 O2 供应中的相对作用可以使用一个简单的模型来估计，该模型由与血液接触的 O2 消耗组织块（灌注 Q，O2 平衡曲线 β 的斜率）通过 O2 扩散阻力（O2 扩散能力 D）组成。决定性变量是“平衡指数”Y=D/(Qbeta)。随着 Y 的减小，扩散限制增加，灌注限制减少（Y > 3 表示主要灌注限制；3 > Y > 0.1，联合灌注和扩散限制，Y < 0.1，主要扩散限制）。根据人类最大摄氧量的文献数据，肌肉的氧气供应始终受到灌注和扩散的限制。在常氧状态下，灌注限制很普遍，但在缺氧状态下，弥散限制则成为主要现象。基础模型假设肌肉在氧气需求、扩散条件和血流方面具有完美的同质性。在对孤立肌肉和原位肌肉的大量研究中，发现了血流的明显异质性，在运动期间和最大氧气摄取时也是如此。结果表明，与均质模型相比，由于血流和/或 O2 扩散能力分布不均，O2 传输效率会降低。因此，基于均质模型计算的扩散能力值低估了真实的扩散能力，并且高估了扩散极限。
The relative roles of blood flow (perfusion) and diffusion in O2 supply to exercising muscle can be estimated using a simple model consisting of an O2-consuming tissue block in contact with blood (perfusion Q, slope of O2 equilibirum curve beta) through a resistance to O2 diffusion (O2-diffusing capacity D). The decisive variable is the 'equilibration index' Y=D/(Qbeta). With decreasing Y, diffusion limitation increases and perfusion limitation decreases (Y > 3 indicates predominant perfusion limitation; 3 > Y > 0.1, combined perfusion and diffusion limitation, Y < 0.1, prevailing diffusion limitation). On the basis of literature data on humans at maximum O2 uptake, O2 supply to muscle is shown to be always limited by both perfusion and diffusion. In nomoxia, perfusion limitation is prevalent, but in hypoxia diffusion limitation becomes predominant. The underlying model assumes perfect homogeneity of muscles with respect to O2 requirement, diffusion conditions and blood flow. In numerous studies on isolated and in situ muscles a pronounced heterogeneity of blood flow has been found, also during exercise and at maximal O2 uptake. It is shown that with unequal distribution of blood flow and/or O2-diffusing capacity the efficiency of O2 transfer is reduced with reference to the homogeneous model. Therefore, the diffusing capacity value calculated on the basis of the homogeneous model is an underestimate of the true diffusing capacity and diffusion limitation is overestimated.
血红蛋白浓度对犬腓肠肌原位最大摄氧量的影响。
DOI：
10.1152/jappl.1991.70.3.1105
发表时间：
1991
期刊：
Journal of applied physiology (Bethesda, Md. : 1985)
影响因子：
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作者：
Hogan,MC;Bebout,DE;Wagner,PD
通讯作者：
Wagner,PD