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首页> 外文期刊>Journal of pharmacokinetics and biopharmaceutics >Diffusion-limited, but not perfusion-limited, compartmental models describe cerebral nitrous oxide kinetics at high and low cerebral blood flows.
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Diffusion-limited, but not perfusion-limited, compartmental models describe cerebral nitrous oxide kinetics at high and low cerebral blood flows.

机译：扩散受限而不是灌注受限的区室模型描述了在高和低脑血流量下的一氧化二氮动力学。

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This study aimed to evaluate the relative importance of diffusion-limited vs. perfusion-limited mechanisms in compartmental models of blood-tissue inert gas exchange in the brain. Nitrous oxide concentrations in arterial and brain efferent blood were determined using gas chromatographic analysis during and after 15 min of nitrous oxide inhalation, at separate low and high steady states of cerebral blood flow (CBF) in five sheep under halothane anesthesia. Parameters and model selection criteria of various perfusion- or diffusion-limited structural models of the brain were estimated by simultaneous fitting of the models to the mean observed brain effluent nitrous oxide concentration for both blood flow states. Perfusion-limited models returned precise, credible estimates of apparent brain volume but fit the low CBF data poorly. Diffusion-limited models provided better overall fit of the data, which was best described by exchange of nitrous oxide between a perfusion-limited brain compartment and an unperfused compartment. In individual animals, during the low CBF state, nitrous oxide kinetics displayed either fast, perfusion-limited behavior or slow, diffusion-limited behavior. This variability was exemplified in the different parameter estimates of the diffusion limited models fitted to the individual animal data sets. Results suggest that a diffusion limitation contributes to cerebral nitrous oxide kinetics.
机译：这项研究旨在评估脑中血液组织惰性气体交换的隔室模型中扩散受限与灌注受限机制的相对重要性。在氟烷麻醉下，五只绵羊在脑血流量（CBF）分别处于低和高稳态时，在吸入一氧化二氮期间和之后15分钟和之后，使用气相色谱分析法测定了动脉和脑传出血液中一氧化二氮的浓度。通过同时将模型拟合到两种血流状态下观察到的脑流出物中一氧化二氮的平均浓度，可以估算出各种灌注受限或扩散受限的大脑结构模型的参数和模型选择标准。灌注受限模型返回了对表观大脑体积的精确，可靠的估计，但对低CBF数据的拟合较差。扩散受限的模型提供了更好的数据整体拟合度，这可以通过在灌注受限的脑室和未灌注的室之间交换一氧化二氮来最好地描述。在个别动物中，在低CBF状态下，一氧化二氮动力学表现出快速的，灌注受限的行为或缓慢的，扩散受限的行为。这种变异性体现在适合个体动物数据集的扩散受限模型的不同参数估计中。结果表明扩散限制有助于大脑一氧化二氮动力学。

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