Regulation of the Pulmonary Ventilation in Pulmonary Emphysema:  Priority of Respiratory Effort Over the Respiratory Center

Although the respiratory center of normal persons responds to carbon dioxide with a predictable increase in minute volume of ventilation, the patient with pulmonary emphysema manifests a relatively lower increment of ventilation to inhalation of a given carbon dioxide percentage (Scott¹). This difference in response has been commonly explained on the basis of impairment of the sensitivity of the respiratory center, due to the presence of hypercapnia in this entity.^2-5 However, other investigators have recently presented sound physiologic evidence which suggests that the lowered ventilatory response to carbon dioxide is caused by limitation in the maximal breathing capacity and that there is no demonstrable impairment of the respiratory center itself.^6-8 As a result of analyzing previous data from our clinic as well as findings of more recent investigations,^9,10 I propose the concept that the work of breathing, including the factor responsible for respiratory effort, frequently takes precedence over the activity