ACCLIMATIZATION TO CARBON DIOXIDE

Abstract

The acclimatization of dogs to atmospheres rich in CO2 (1.5 to 5.0%) was studied. The following changes in acid-base balance, water and electrolyte distr. and blood cells and Hb were noted: There was a mild, uncompensated acidosis (pH 7.20 to 7.30) with a decline in CO2 combining power interpreted as an exchange of blood bicarbonate for tissue lactate or chloride. A transfer of chloride from plasma to erythrocytes occurred and a decrease in whole blood chloride. The ratio of cell bicarbonate to plasma bicarbonate increased, as did the mean corpuscular vol. of the erythrocytes. Erythrocyte count and Hb conc. increased after a variable latent period. The bone marrow origin of this increase was indicated by the rise in reticulocyte count, the negative influence of splenectomy and the absence of hemoconc. The adm. of 35% O with the CO2, although increasing the saturation of the arterial blood above normal, had no effect on the erythrocyte increase. The bone marrow stimulation was due to a tissue anoxia resulting from depression of tissue oxidations by CO2. The total leucocyte count increased greatly but there was no significant change in the differential count.