🫁 Ventilatory Ratio (VR)
UseWhen to use: ventilated patients (often ARDS) when V̇E, PaCO₂, and PBW are known.
StrataHigher VR → more dead-space / inefficient CO₂ clearance.
LimitsWhen not to use: as sole weaning criterion. · Pitfall: using actual obese weight instead of PBW. · Interpret with P/F and driving pressure.
SourceSinha P et al. Ventilatory ratio
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
Dimensionless VR.
When to use
When to use: ventilated patients (often ARDS) when V̇E, PaCO₂, and PBW are known.
How it works
VR=(V̇E×PaCO₂)/(PBW×0.1×37.5) with V̇E in L/min.
Key points
- Dimensionless VR.
- Ideal PaCO₂ 37.5.
- Next: ARDS bundle review.
References
- Sinha P et al. Ventilatory ratio
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.
| Minute ventilation (V̇E) | 8.5 L/min |
|---|---|
| PaCO₂ | 45 mmHg |
| Predicted body weight | 70 kg |
→Ventilatory ratio1.46
- Cue：VR <1.5 — nearer predicted ventilatory efficiency
- Ideal PaCO₂：37.5 mmHg in denominator
Verification & sources · governance
FAQ
Frequently asked questions
- Does Ventilatory Ratio (VR) 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 Ventilatory Ratio (VR) calculated in practice? Can you show a worked example?
- Inputs: Minute ventilation (V̇E) 8.5 L/min, PaCO₂ 45 mmHg, Predicted body weight 70 kg → Result: Ventilatory ratio 1.46（Cue: VR <1.5 — nearer predicted ventilatory efficiency, Ideal PaCO₂: 37.5 mmHg in denominator）