A METHOD OF OBTAINING ALVEOLAR AIR FROM NORMAL DOGS AND A COMPARISON OF THE CARBON DIOXIDE TENSIONS OF ALVEOLAR AIR AND ARTERIAL BLOOD

Abstract

A method is described for obtaining alveolar air in normal unanesthetized dogs. The apparatus consists of a close fitting respiratory mask connected to a valvular arrangement which separates the inspired from the expired air. The last portion of the expired air in a series of consecutive respirations is automatically collected into a sampling tube by mercury displacement. The air collected by this method in man approximated the second Haldane-Priestley sample. Equilibrium for CO2 but not for O is shown to exist between such samples of alveolar air and arterial blood drawn synchronously from the left ventricle. An appreciable variation of the CO2 dissociation curve in the physiological region in dogs is indicated.