ROX Index (HFNC failure prediction)
ROX index (Roca 2019) = (SpO2/FiO2)/respiratory rate; predicts HFNC success.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- SpO2
- 94 %
- FiO2
- 0.5
- Respiratory rate
- 24 breaths/min
- Hours after HFNC start
- 12
Result: ROX 7.83: success-predicting (>=4.88 per Roca 2019).
The tool opens with these values already filled in. Replace them with your own.
What the result means
- >=4.88
- Success-predicting per Roca 2019 (cutoff >=4.88 at 2 / 6 / 12 h post-HFNC start).
- failure cutoff
- Failure-predicting at the stated time point per Roca 2019 Figure 2 (<2.85 at 2 h; <3.47 at 6 h; <3.85 at 12 h).
What you enter
- SpO2
- FiO2 (0-1)
- Respiratory rate
- Hours after HFNC start (2 / 6 / 12; needed only where the timepoint decides)
How this is calculated
Roca O, Caralt B, Messika J, et al. An index combining respiratory rate and oxygenation to predict outcome of nasal high-flow therapy. Am J Respir Crit Care Med. 2019;199(11):1368-1376. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.