Abstract
This is a consideration of the relationships between the uneven ventilation of the lung and the arterial oxygen saturation and CO2 tension. In the simplest case, the lung is considered to contain only two differently ventilated and perfused components. Graphic methods are developed for dealing with situations of this type and illustrated by application to the data obtained in a normal subject. Some of the methods outlined here can be applied in situations where the lung is composed of three or more differently ventilated and perfused components. In the normal subject considered here, the uneven ventilation of the lung is compatible with A-a gradients of 6 and 0.8 mm for O2 and CO2, respectively. Submitted on October 3, 1958