Abstract

Maranetra, N. and Pain, M. C. F. (1974). Thorax, 29, 578-581. Ventilatory drive and ventilatory response during rebreathing. The increase in inspiratory airway pressure generated against a transiently occluded airway during rebreathing is proposed as a simple index of ventilatory drive (ΔP/ΔPco₂). A study of this index in 12 normal subjects and 50 patients with chronic airways obstruction demonstrated no significant difference between normals and patients in ΔP/ΔPco₂ despite an overall reduction in the ventilatory response to carbon dioxide (ΔV̇e/ΔPco₂) in the patients. A significant association was demonstrated between the ventilatory response to carbon dioxide, ΔP/ΔPco₂ and the degree of airways obstruction. Patients with a low ΔP/ΔPco₂ showed greater hypoxaemia, hypercapnia, and polycythaemia than patients with a higher ΔP/ΔPco₂ for the same degree of airways obstruction.