Calculates expected respiratory compensation in metabolic acidosis using Winter's formula.
Expected PaCO₂ in Metabolic Acidosis: Clinical Guide
Browse Knowledge HubCalculates expected respiratory compensation in metabolic acidosis using Winter's formula.
Overview
Calculates expected respiratory compensation in metabolic acidosis using Winter’s formula.
Clinical Significance
Compares measured PaCO₂ with expected compensation. A value outside the expected range suggests an additional respiratory disorder.
How It Is Calculated
- Expected PaCO₂ = 1.5 × HCO₃⁻ + 8 ± 2 mmHg.
Interpretation
- Compares measured PaCO₂ with expected compensation. A value outside the expected range suggests an additional respiratory disorder.
Worked Example
Enter a clinically consistent set of values in the displayed units. MedicalC applies: Expected PaCO₂ = 1.5 × HCO₃⁻ + 8 ± 2 mmHg.
Limitations
- This tool does not establish a diagnosis or mandate treatment.
- Published cut-offs may vary between cohorts and measurement methods.
- Calculation precision cannot compensate for poor source data.
Clinical Pearls
- Trend the result over time where clinically appropriate.
- Record the source values and units alongside the calculated result.
Common Mistakes
- Using the wrong unit.
- Combining measurements obtained at different times.
- Applying a research-derived threshold as a universal treatment trigger.
Frequently Asked Questions
What does this calculator provide?
Calculates expected respiratory compensation in metabolic acidosis using Winter’s formula.
Can this result be used alone?
No. It must be interpreted with clinical context and appropriate investigations.
What equation is used?
Expected PaCO₂ = 1.5 × HCO₃⁻ + 8 ± 2 mmHg.
What is the main limitation?
The result depends on valid inputs and may not be calibrated for every population or setting.
References
- Albert MS et al. Quantitative displacement of acid-base equilibrium in metabolic acidosis. Ann Intern Med. 1967. — Formula, physiological or validation reference.
Reviewed by: MedicalC Clinical Editorial Team
Last reviewed: July 2026
Clinical Disclaimer
MedicalC calculators and clinical tools are intended to support healthcare professionals. They do not replace clinical judgement, individual patient assessment, local guidance or specialist advice.
Results should always be interpreted in the context of the patient’s history, examination, investigations, current clinical condition and applicable professional guidance.