Fraction of maximum breathing capacity available for prolonged hyperventilation

¹ Department of Medicine, Columbia University, College of Physicians and Surgeons; and Cardio-Pulmonary Laboratory, First Medical and Chest Services (Columbia University Division), Bellevue Hospital, New York City

The volume of ventilation which nine healthy young men could maintain for 15 minutes was only 53% of the maximum breathing capacity (MBC). A similar figure was obtained for older patients with chronic pulmonary emphysema. These data suggest that the MBC is not the limiting response to be expected from stimuli such as hypoxia or hypercapnia, and that the capacity of a patient for maintaining an augmented minute volume is an important determinant of the responses these stimuli evoke.