STUDIES ON INTRAPULMONARY MIXTURE OF GASES. V. FORMS OF INADEQUATE VENTILATION IN NORMAL AND EMPHYSEMATOUS LUNGS, ANALYZED BY MEANS OF BREATHING PURE OXYGEN

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Abstract
The effectiveness of intrapulmonary mixing of inhaled tidal air, during quiet breathing, was measured in 18 normal subjects and in 5 patients with severe pulmonary emphysema, by means of the analysis of respiratory gases during the breathing of pure oxygen. In some normal subjects, there was nearly perfect mixing of inhaled tidal air through the lungs. Other apparently normal subjects, especially some of the older ones, gave evidence of imperfect intrapulmonary mixing. The latter was marked in 4 of 5 patients with pulmonary emphysema. It was possible to demonstrate, in actual clinical cases, the distinction between inadequate ventilation of pulmonary spaces due to greatly increased residual air, and that due to unequal mixture of tidal air through these spaces. An estimation of the extent of underventilation of pulmonary spaces, in successive samples of alveolar air from normal and diseased subjects, provided some evidence against the existence of any systematic alternation of function of discrete groups of alveoli.