Regulation of respiration during oxygen breathing in chronic obstructive lung disease.

In contrast to previous studies in which arterial hypoxia in patients with chronic obstructive pulmonary disease did not appear to be a major factor influencing their subsequent ventilatory response to an oxygen test, the degree of pre-existing hypoxia in this study of 151 patients was significantly correlated with the amount of ventilatory depression observed during subsequent oxygen administration. On the other hand, arterial pH, which was of high significance in other studies, had the lowest correlation in this study. The variability of ventilatory responses observed by others in smaller groups of patients has been confirmed, and no combination of factors related to arterial carbon dioxide tension, arterial oxygen tension, or pH could be identified to account for this variability. Patients who manifested a priority for diminution of dyspnea rather than a constancy of arterial carbon dioxide tension did not correspond to the bronchitic type B patients of Burrows and associates, because in this study, pa...