🧪 Acid-Base Compensation Predictor
Predict the expected compensation for a primary acid-base disorder; deviation from the expected value suggests a coexisting second disorder.
Acid-Base Compensation Predictor
Primary disorder
HCO₃⁻ (for metabolic disorders) (mmol/L)
PaCO₂ (for respiratory disorders) (mmHg)
When to use
Identify mixed acid-base disorders on a blood gas by comparing measured with expected compensation.
How it works
Metabolic acidosis: expected PaCO₂ = 1.5·HCO₃ + 8 (Winter's). Metabolic alkalosis: 0.7·HCO₃ + 21. Acute/chronic respiratory acidosis & alkalosis use fixed HCO₃ change per 10 mmHg PaCO₂.
Key points
- Compensation never overcorrects — values beyond the expected range mean a mixed disorder.
- Always interpret with pH and the anion gap.
- Winter's formula carries ± 2 mmHg uncertainty.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.