🫧 Dead Space Fraction (Bohr/Enghoff Vd/Vt)
UseWhen to use: unexplained hypercapnia, PE suspicion, or ARDS monitoring.
StrataRising fraction suggests more wasted ventilation (PE, low Q, overdistension).
LimitsWhen not to use: PETCO₂ as exact mixed expired without caveat. · Pitfall: units mismatch mmHg vs kPa. · Integrate hemodynamics.
SourceBohr / Enghoff dead-space equation
This-shift next steps
After scoring: open the scene pack, peer scores, and the matching pathway. Local reference — no HIS write.
Paste the link in Slack, Teams, X, or LinkedIn — the preview image comes from this page’s Open Graph card.
Methodology · worked example, guidelines & full notes
(Pa−PE)/Pa.
When to use
When to use: unexplained hypercapnia, PE suspicion, or ARDS monitoring.
How it works
Vd/Vt = (PaCO₂ − PECO₂)/PaCO₂ (PETCO₂ often substituted).
Key points
- (Pa−PE)/Pa.
- Dead-space fraction.
- Next: PE/vent review.
References
- Bohr / Enghoff dead-space equation
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| PaCO₂ | 45 mmHg |
|---|---|
| PECO₂ or PETCO₂ | 30 mmHg |
→Vd/Vt0.33fraction
- Percent：33%
- Cue：≤0.40 — nearer normal physiologic band (context-dependent)
Verification & sources · governance
FAQ
Frequently asked questions
- Does Dead Space Fraction (Bohr/Enghoff Vd/Vt) upload patient data? Where is it calculated?
- Calculation runs locally in the browser; inputs and results are not uploaded. For licensed clinicians only; interpret with history, investigations and local protocols — not a diagnosis or prescription.
- How is Dead Space Fraction (Bohr/Enghoff Vd/Vt) calculated in practice? Can you show a worked example?
- Inputs: PaCO₂ 45 mmHg, PECO₂ or PETCO₂ 30 mmHg → Result: Vd/Vt 0.33 fraction（Percent: 33%, Cue: ≤0.40 — nearer normal physiologic band (context-dependent)）