Expected HCO3 (respiratory acidosis)
Expected HCO3 in respiratory acidosis (Brackett 1965 acute; Schwartz 1965 chronic): the appropriate-compensation band vs the measured HCO3.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Measured PaCO2
- 60 mmHg
- Measured HCO3
- 26 mEq/L
- Acute or chronic
- Acute
Result: Expected HCO3 26 mEq/L (acute, +1 per 10 mmHg): the measured 26 mEq/L matches the expected 26 mEq/L (+/-2), consistent with appropriate compensation.
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Reading
- a measured HCO3 below the expected band suggests an added metabolic acidosis; above it, an added metabolic alkalosis.
What you enter
- Measured PaCO2
- Measured HCO3
- Acute or chronic
How this is calculated
- Formula
- expected HCO3 = 24 + k x (PaCO2 - 40)/10; k = 1 acute, 4 chronic (3.5-4 range).
Brackett NC Jr, Cohen JJ, Schwartz WB. Carbon dioxide titration curve of normal man. N Engl J Med. 1965;272:6-12; chronic adaptation per Schwartz WB, et al. 1965. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.