Blood reaction and respiration.

Abstract

Experimental and clinical observations indicate that when the respiratory mechanism is normal, increase in alkaline reserve is only partially compensated by increase in CO2 tension, so that increase in pH also occurs. In the same way decrease in alkaline reserve is accompanied by decrease in pH. There is a decrease in CO2 tension but not sufficient to prevent pH change. The usual percentage change in hydrion concentration is about twice that in CO2 tension. The arterial CO2 tension is kept normally between 35 to 45 mm., which is a much narrower range than would be necessitated for the maintenance of normal pH. The conception of the CO2 tension as a factor physiologically important only from its relationship to blood pH is not consistent with these facts. When conditions force the organism to choose between change in CO2 tension and change in pH it tends to compromise between the two, and acts in a manner to indicate that maintenance of normal CO2 tension is in itself an important factor.