PaCO2
Medical abbreviation · Laboratory Test
| Stands for | Partial pressure of arterial carbon dioxide |
|---|---|
| Categories | Medical |
PaCO2 stands for Partial pressure of arterial carbon dioxide, a laboratory test abbreviation.
Pressure of carbon dioxide in arterial blood, normally 35 to 45 mmHg, and the direct measure of how well alveolar ventilation clears CO2. A high PaCO2 indicates hypoventilation and respiratory acidosis; a low value indicates hyperventilation and respiratory alkalosis.
Example: PaCO2 82 and somnolent after opioids; naloxone given and BiPAP applied.
Usage notes
As a rule of thumb, an acute 10 mmHg rise in PaCO2 lowers pH by about 0.08, whereas in chronic retention kidney compensation limits the fall to about 0.03. Intensive care teams sometimes accept higher levels (permissive hypercapnia) to protect injured lungs. End-tidal CO2 tracks PaCO2 but usually reads a few mmHg lower.
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This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.