A model of the chemoreflex control of breathing in humans: model parameters measurement
A model of the chemoreflex control of breathing in humans: model parameters measurement
复制标题
DOI：
10.1016/s0034-5687(00)00095-5
复制
发表时间：
2000-03-01
期刊：
影响因子：
--
通讯作者：
Mahamed, S
中科院分区：
文献类型：
--
作者：
Duffin, J;Mohan, RM;Mahamed, S
我们回顾了22名受试者的再呼吸实验中获得的解释性反应。我们的目的是获得一个“平均受试者”的参数估计，以便模拟呼吸化学反射控制系统。对所用的再呼吸技术进行了修改，以包括先前的过度通气，因此再呼吸开始于低碳酸血症P-CO2，结束于高碳酸血症P-CO2。此外，以受控方式向再呼吸袋中添加氧气，以在再呼吸期间维持等氧，这允许在几个等氧P-O2水平下测定反应。根据潮气量、呼吸频率和通气量分析逐呼吸反应。随着P-CO2升高，通气量首先稳定在基础值，然后随着P-CO2超过断点而增加。我们将第一个断点解释为中枢和外周化学反射反应的阈值。以上，通气量随P-CO2线性增加。潮气量通常比频率对增加的贡献更大。当呼吸被强烈驱动时，例如在缺氧中，经常观察到第二个断点P-CO2。超过第二个断点，通气量继续以不同的斜率随P-CO2线性增加。频率通常比潮气量对增加的贡献更大。我们定义的参数的潮气量，频率和通气量的变化与P-O2和P-CO2的平均受试者的个人响应的三段线性拟合的基础上。这些被纳入到一个模型的呼吸化学反射控制系统的基础上的“牛津”模型的一般计划。然而，该模型不仅考虑了呼吸响应，还结合了潮气量和频率响应。(C)2090 Elsevier Science B. V.保留所有权利。
We reviewed the ventilatory responses obtained from rebreathing experiments on a population of 22 subjects. Our aim was to derive parameter estimates for an 'average subject' so as to model the respiratory chemoreflex control system. The rebreathing technique used was modified to include a prior hyperventilation, so that rebreathing started at a hypocapnic P-CO2 and ended at a hypercapnic P-CO2. In addition, oxygen was added to the rebreathing bag in a controlled manner to maintain iso-oxia during rebreathing, which allowed determination of the response at several iso-oxic P-O2 levels. The breath-by-breath responses were analysed in terms of tidal volume, breathing frequency and ventilation. As P-CO2 rose, ventilation was first steady at a basal value, then increased as P-CO2 exceeded a breakpoint. We interpreted this first breakpoint as the threshold of the combined central and peripheral chemoreflex responses. Above, ventilation increased linearly with P-CO2. With tidal volume usually contributing more than frequency to the increase. When breathing was driven strongly, such as in hypoxia, a second breakpoint P-CO2 was often observed. Beyond the second breakpoint, ventilation continued to increase linearly with P-CO2 at a different slope. with frequency usually contributing more than tidal volume to the increase. We defined the parameters of the variation of tidal volume, frequency and ventilation with P-O2 and P-CO2 for an average subject based on a three-segment linear fit of the individual responses. These were incorporated into a model of the respiratory chemoreflex control system based on the general scheme of the 'Oxford' model. However, instead of considering ventilatory responses alone, the model also incorporates tidal volume and frequency responses. (C) 2090 Elsevier Science B.V. All rights reserved.