Assess respiratory compensation in the presence of metabolic acidosis.
ABG / BMP Values
mmol/L
mmHg
Compensation Result
Expected PaCO₂30.5mmHgRange: 28.5 - 32.5
Clinical StateAppropriate Compensation
The respiratory system is compensating correctly.
Interpretation requires a confirmed primary metabolic acidosis. Compensation takes 12-24 hours to reach maximum effect.
About this calculator
Overview
Winters' Formula is used to calculate the expected partial pressure of carbon dioxide (PaCO₂) in a patient with metabolic acidosis. It determines whether the respiratory system is compensating appropriately for the acid-base disturbance.
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Pro Tips
Bicarbonate levels are found on a basic metabolic panel (BMP) or arterial blood gas (ABG).
The formula only applies to patients with a primary metabolic acidosis.
Maximum compensation typically reaches a PaCO₂ floor of about 10-15 mmHg.
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Fun Facts
"Metabolic acidosis should always trigger a compensatory increase in ventilation (lowering PaCO₂)."
"If the measured PaCO₂ matches the expected value, the respiratory compensation is appropriate."
"A Measured PaCO₂ higher than expected suggests a concomitant respiratory acidosis."
"A Measured PaCO₂ lower than expected suggests a concomitant respiratory alkalosis."
