Above the range
Common causes of a high PaCO₂ (Arterial CO₂)
- Hypoventilation (respiratory acidosis)
- COPD
- Sedation / respiratory depression
Looking for the other direction? See what causes a low PaCO₂ (Arterial CO₂).
All tests · Arterial Blood Gas (ABG) · PaCO₂ (Arterial CO₂)
Above the range
What causes a high PaCO₂ (Arterial CO₂)?
Normal range 35-45 mm Hg (4.7-6 kPa SI). Specimen: Arterial blood. See the full PaCO₂ (Arterial CO₂) reference page for critical values and nursing considerations.
What is the normal range for PaCO₂ (Arterial CO₂)?
The standard teaching reference range for PaCO₂ (Arterial CO₂) is 35-45 mm Hg in conventional units, or 4.7-6 kPa in SI units. This value is measured in arterial blood.
| Specimen | Arterial blood |
|---|---|
| Conventional range | 35-45 mm Hg |
| SI range | 4.7-6 kPa |
| Critical value | < 20 or > 60 mm Hg |
| Panel | Arterial Blood Gas (ABG) |
Full details, including nursing considerations, on the PaCO₂ (Arterial CO₂) normal range page. Reference ranges vary by laboratory, method, age, sex, and population - always use the range printed on the actual result.
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