partial pressure of carbon dioxide in arterial blood (PaCO2), the portion 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 reference interval is 35-45 mm Hg in arterial blood and 40-45 mm Hg in venous blood.
