ROX Index (HFNC Outcome) — free guideline decision tool
Predict high-flow nasal cannula success with the ROX index in acute hypoxaemic respiratory failure.
Open guideline tool →Guideline-based
Implements the decision logic from published clinical guidelines.
Runs in your browser
No installation. Enter the patient's values and get a guideline recommendation instantly.
Data stays local
Nothing is uploaded. Results are for licensed clinicians only.
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.
| SpO₂ | 94 % |
|---|---|
| FiO₂ | 0.5 fraction |
| Respiratory rate | 24 /min |
→ROX index7.83
- Interpretation：≥ 4.88 — lower risk of HFNC failure.
- Formula：(SpO₂% / FiO₂) / respiratory rate
Common questions
What is ROX Index (HFNC Outcome)?
Predict high-flow nasal cannula success with the ROX index in acute hypoxaemic respiratory failure.
How is ROX Index (HFNC Outcome) calculated? What is the core formula?
ROX = (SpO₂% / FiO₂) / respiratory rate. ≥ 4.88 predicts success; < 3.85 suggests failure.
When is ROX Index (HFNC Outcome) used?
Monitor response to HFNC and flag impending failure.
What are the key clinical points for ROX Index (HFNC Outcome)?
Assess at ~2, 6 and 12 hours of HFNC. Persistently low values warrant considering intubation. Combines oxygenation and respiratory drive in one number.
What are the limits and cautions when using ROX Index (HFNC Outcome)?
For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
How is ROX Index (HFNC Outcome) calculated in practice? Can you show a worked example?
Inputs: SpO₂ 94 %, FiO₂ 0.5 fraction, Respiratory rate 24 /min → Result: ROX index 7.83（Interpretation: ≥ 4.88 — lower risk of HFNC failure., Formula: (SpO₂% / FiO₂) / respiratory rate）
Run ROX Index (HFNC Outcome) now
Predict high-flow nasal cannula success with the ROX index in acute hypoxaemic respiratory failure.
Open guideline tool →For licensed clinicians. Not a substitute for clinical judgement.
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