Extensive psychophysical experiments have established that the sense of respiratory effort bears a power function relationship to the force generated by respiratory muscles and the frequency and duration of their contraction, and an inverse relationship to respiratory muscle strength. Using this information an approach to the assessment of dyspnea is developed which has several components. First, the response to exercise, in terms of the metabolic and gas exchange demands is established. Second, the ventilatory responses are analyzed in terms of total ventilation, the pattern of breathing (tidal volume and breathing frequency), and the timing of breathing (inspiratory and expiratory times). Third, the exercise measurements are considered in relation to the elastic and resistive components of the respiratory system that impede volume and flow, as reflected in measurements of static lung volume and the flow:volume characteristic. Finally, measurement of the maximum inspiratory pressure against an occluded airway reflects respiratory muscle strength. Dyspnea, the sensation of increased respiratory effort, is usually due to a combination of abnormalities--increased metabolic demand, increased ventilatory response, increased impedance to breathing, and reduced respiratory muscle power. Management of abnormality in each of these components is distinctly separate.
大量的心理物理学实验已经证实，呼吸用力的感觉与呼吸肌产生的力量及其收缩的频率和持续时间呈幂函数关系，与呼吸肌力量呈反比关系。利用这些信息，开发了一种评估呼吸困难的方法，该方法包括几个部分。首先，确定运动时的代谢和气体交换需求方面的反应。其次，从总通气量、呼吸模式（潮气量和呼吸频率）以及呼吸时间（吸气和呼气时间）方面分析通气反应。第三，将运动测量结果与阻碍容积和气流的呼吸系统弹性和阻力成分相关联，这反映在静态肺容积测量和流量-容积特性中。最后，测量对抗阻塞气道的最大吸气压力反映呼吸肌力量。呼吸困难，即呼吸用力增加的感觉，通常是由于多种异常情况共同作用的结果——代谢需求增加、通气反应增加、呼吸阻抗增加以及呼吸肌力量降低。对这些组成部分中每一个异常情况的处理是截然不同的。
