Calculator

ROX index

New

(SpO₂/FiO₂) ÷ respiratory rate, for patients on HFNC. Assess at 2, 6 and 12 h.

%
fraction
/min

ROX

6.64

Lower risk of intubation (≥ 4.88)

High risk of HFNC failure (< 3.85 at 12 h; < 2.85 at 2 h, < 3.47 at 6 h)
Indeterminate: reassess in 1-2 h
Lower risk of intubation (≥ 4.88)

Formula

(spo2 / fio2) / rr

References

  1. Roca O, et al. An index combining respiratory rate and oxygenation to predict outcome of nasal high-flow therapy. Am J Respir Crit Care Med 2019;199:1368-76.

Used in

High-flow nasal oxygen and the ROX indexSevere community-acquired pneumonia

Calculators support, not replace, clinical judgement. Check inputs and units, and confirm doses with your unit protocol.