Oku Y, Saidel G M, Chonan T, Altose M D, Cherniack N S
Department of Medicine, Case Western Reserve University, Cleveland, OH 44106.
Ann Biomed Eng. 1991;19(3):251-72. doi: 10.1007/BF02584302.
A dynamic model of the CO2 respiratory control system is proposed, which can provide a qualitative basis for predicting breathing sensations. The discomfort index, which represents breathing sensations, is assumed to be composed of two sources: the arterial CO2 level and the respiratory motor command. The respiratory controller receives inhibitory neuromechanical and excitatory CO2 signals from the plant. The CO2 signal is enhanced by exercise stimuli. This dynamic multiplicative-type controller is used in simulations of key experiments: exercise and CO2 rebreathing with and without resistive loading. The dynamics of the discomfort index, the respiratory motor command, ventilation, and arterial CO2 concentration conform to the experimental data. The perceptual sensitivity to CO2 relative to respiratory effort is significantly correlated with the slope of hypercapnic ventilatory response. This result shows a clear linkage between ventilatory response and breathing sensations. Although it is shown that the automatic controller effectively minimizes the discomfort index for perturbations about an operating point under certain conditions, the discomfort index itself does not seem to be an underlying control principle of the proposed automatic controller model. Rather, breathing sensations may influence ventilatory responses by modifying the output of the automatic controller.
提出了一种二氧化碳呼吸控制系统的动态模型，该模型可为预测呼吸感觉提供定性依据。代表呼吸感觉的不适指数被假定由两个来源组成：动脉血二氧化碳水平和呼吸运动指令。呼吸控制器从被控对象接收抑制性神经机械信号和兴奋性二氧化碳信号。二氧化碳信号通过运动刺激得到增强。这种动态乘法型控制器用于关键实验的模拟：有无阻力负荷情况下的运动和二氧化碳再呼吸。不适指数、呼吸运动指令、通气量和动脉血二氧化碳浓度的动态变化与实验数据相符。相对于呼吸努力而言，对二氧化碳的感知敏感性与高碳酸通气反应的斜率显著相关。这一结果表明通气反应与呼吸感觉之间存在明显联系。虽然结果表明自动控制器在某些条件下能有效地将关于工作点的扰动引起的不适指数降至最低，但不适指数本身似乎并不是所提出的自动控制器模型的潜在控制原理。相反，呼吸感觉可能通过改变自动控制器的输出影响通气反应。
