Calculates the Enghoff modification of dead-space fraction using arterial and mixed-expired carbon dioxide.
Overview
Calculates the Enghoff modification of dead-space fraction using arterial and mixed-expired carbon dioxide.
Clinical Significance
The Enghoff modification incorporates shunt and ventilation–perfusion inequality as well as true dead space; it should not be interpreted as purely anatomical dead space.
How It Is Calculated
- VD/VT (Enghoff) = (PaCO₂ − PECO₂) / PaCO₂.
Interpretation
- The Enghoff modification incorporates shunt and ventilation–perfusion inequality as well as true dead space; it should not be interpreted as purely anatomical dead space.
Worked Example
Enter a clinically consistent set of values in the displayed units. MedicalC applies: VD/VT (Enghoff) = (PaCO₂ − PECO₂) / PaCO₂.
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 the Enghoff modification of dead-space fraction using arterial and mixed-expired carbon dioxide.
Can this result be used alone?
No. It must be interpreted with clinical context and appropriate investigations.
What equation is used?
VD/VT (Enghoff) = (PaCO₂ − PECO₂) / PaCO₂.
What is the main limitation?
The result depends on valid inputs and may not be calibrated for every population or setting.
References
- Enghoff H. Volumen inefficax. Bemerkungen zur Frage des schädlichen Raumes. Upsala Läkarefören Förh. 1938. — Formula, physiological or validation reference.
Reviewed by: MedicalC Clinical Editorial Team
Last reviewed: July 2026