partial pressure of carbon dioxide in arterial blood

partial pressure of carbon dioxide in arterial blood (PaCO₂),

the part of total blood gas pressure exerted by carbon dioxide. It decreases during heavy exercise, during rapid breathing, or in association with severe diarrhea, uncontrolled diabetes, or diseases of the liver or kidneys. It increases with chest injuries or respiratory disorders. The normal pressures of carbon dioxide in arterial blood are 35 to 45 mm Hg and, in venous blood, 40 to 45 mm Hg.