🩸 Oxygen Extraction Ratio (O₂ER)
UseWhen to use: shock / ICU oxygen-supply assessment with content or VO₂/DO₂ data.
StrataRising O₂ER suggests high extraction demand or falling delivery.
LimitsWhen not to use: unreliable mixed/central venous sample. · Pitfall: treating ScvO₂ as SvO₂ without caveat. · Dissolved O₂ ignored in sat-only mode.
SourceStandard oxygen extraction ratio
This-shift next steps
After scoring: open the scene pack, peer scores, and the matching pathway. Local reference — no HIS write.
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Methodology · worked example, guidelines & full notes
(Ca−Cv)/Ca.
When to use
When to use: shock / ICU oxygen-supply assessment with content or VO₂/DO₂ data.
How it works
O₂ER = (CaO₂ − CvO₂) / CaO₂ = VO₂ / DO₂.
Key points
- (Ca−Cv)/Ca.
- VO₂/DO₂.
- Next: DO₂ optimization.
References
- Standard oxygen extraction 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.
| Input mode | SaO₂ & SvO₂ (%) approx |
|---|---|
| CaO₂ | 18 mL/dL |
| CvO₂ | 13 mL/dL |
| SaO₂ | 98 % |
| SvO₂ / ScvO₂ | 70 % |
| VO₂ | 250 mL/min |
| DO₂ | 1000 mL/min |
→O₂ER28.6%
- Method：Saturation approximation (ignores dissolved O₂)
- Percent：28.6%
- Cue：20–34% — common resting extraction band
| Input mode | CaO₂ & CvO₂ (mL/dL) |
|---|---|
| CaO₂ | 18 mL/dL |
| CvO₂ | 13 mL/dL |
| SaO₂ | 98 % |
| SvO₂ / ScvO₂ | 70 % |
| VO₂ | 250 mL/min |
| DO₂ | 1000 mL/min |
→O₂ER27.8%
- Method：Content (Ca−Cv)/Ca
- Percent：27.8%
- Cue：20–34% — common resting extraction band
Verification & sources · governance
FAQ
Frequently asked questions
- Does Oxygen Extraction Ratio (O₂ER) 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 Oxygen Extraction Ratio (O₂ER) calculated in practice? Can you show a worked example?
- Inputs: Input mode SaO₂ & SvO₂ (%) approx, CaO₂ 18 mL/dL, CvO₂ 13 mL/dL, SaO₂ 98 %, SvO₂ / ScvO₂ 70 %, VO₂ 250 mL/min, DO₂ 1000 mL/min → Result: O₂ER 28.6 %（Method: Saturation approximation (ignores dissolved O₂), Percent: 28.6%, Cue: 20–34% — common resting extraction band） Inputs: Input mode CaO₂ & CvO₂ (mL/dL), CaO₂ 18 mL/dL, CvO₂ 13 mL/dL, SaO₂ 98 %, SvO₂ / ScvO₂ 70 %, VO₂ 250 mL/min, DO₂ 1000 mL/min → Result: O₂ER 27.8 %（Method: Content (Ca−Cv)/Ca, Percent: 27.8%, Cue: 20–34% — common resting extraction band）