carbon dioxide (CO2) narcosis, a condition of confusion, tremors, convulsions, and possible coma that may occur if blood levels of carbon dioxide increase to 70 mm Hg or higher. Individuals with chronic obstructive pulmonary disease can have CO2 narcosis without these symptoms because they develop a tolerance to elevated CO2. When ventilation is sufficient to maintain a normal oxygen partial pressure in the arteries, the carbon dioxide partial pressure is generally near 40 mm Hg. See also carbon dioxide poisoning.
