Estimates mean pulmonary artery pressure from systolic pulmonary artery pressure using the Chemla equation.
Estimated Mean Pulmonary Artery Pressure (Chemla): Clinical Guide
Browse Knowledge HubEstimates mean pulmonary artery pressure from systolic pulmonary artery pressure using the Chemla equation.
Overview
Estimates mean pulmonary artery pressure from systolic pulmonary artery pressure using the Chemla equation.
Clinical Significance
Provides an estimate of mean pulmonary artery pressure when direct measurement is unavailable. It does not replace right-heart catheterisation.
When to Use
- Use when the required measurements are available, reliable and clinically relevant.
How It Is Calculated
- Mean PAP ≈ 0.61 × PASP + 2.
Interpretation
- Provides an estimate of mean pulmonary artery pressure when direct measurement is unavailable. It does not replace right-heart catheterisation.
Worked Example
Enter valid values in the displayed units. MedicalC then applies: Mean PAP ≈ 0.61 × PASP + 2.
Limitations
- The result does not establish a diagnosis or mandate treatment.
- Measurement error may be more important than arithmetic precision.
- Published thresholds may differ between populations and settings.
Clinical Pearls
- Document the source values and units with the final result.
- Review trends rather than isolated values where appropriate.
Common Mistakes
- Using the wrong unit.
- Combining values from different time points.
- Applying the result outside the intended measurement or clinical context.
Frequently Asked Questions
What does this calculator provide?
Estimates mean pulmonary artery pressure from systolic pulmonary artery pressure using the Chemla equation.
What formula is used?
Mean PAP ≈ 0.61 × PASP + 2.
Can the result be used alone?
No. It must be interpreted with the full clinical assessment and appropriate investigations.
What is the main limitation?
The result depends on accurate source measurements, correct units and appropriate clinical applicability.
References
- Chemla D et al. New formula for predicting mean pulmonary artery pressure using systolic pulmonary artery pressure. Chest. 2004. — Primary, supporting or authoritative reference for the implemented relationship.
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.