What it means
The body makes carbon dioxide when it uses oxygen and food for energy. In the blood it forms an acid, so the amount helps set the blood's pH: holding too much in makes the blood acidic, and breathing too much off makes it alkaline. The lungs control it by changing how fast and deep a person breathes. On an arterial blood gasar-TEER-ee-ul BLUD GASA blood test from an artery that measures oxygen, carbon dioxide, bicarbonate and the blood's pH.Full entry it is measured as PaCO2.
For the nurse
Slow, shallow breathing, as with opioids or sedation, lets carbon dioxide build up and can make a client drowsy. End-tidal CO2 monitoring tracks breathing during sedation and confirms breathing tube placement.
At a glance
| Normal range | PaCO2 35–45 mm Hg [4.7–6.0 kPa] |
|---|---|
| Abbreviations | CO2; PaCO2 (partial pressure in arterial blood); ETCO2 (end-tidal carbon dioxide) |
| Spanish | dióxido de carbono |
| Also written | CO2 |
Related terms
oxygen
A gas in the air that every cell needs, also given as a medicine at higher amounts than room air.
respiration
Breathing air in and out, and the exchange of oxygen and carbon dioxide between the air, the blood and the cells.
arterial blood gas
A blood test from an artery that measures oxygen, carbon dioxide, bicarbonate and the blood's pH.
acidosis
A state in which the blood is more acidic than normal, with a pH below 7.35.