ROX Index Calculator

SpO2 FiO2 Percentage Respiratory Rate ROX Index Explanation and Clinical Context The ROX Index is a clinical tool used to predict the success of high flow nasal cannula therapy in patients with acute hypoxemic respiratory failure. It is calculated using the ratio of peripheral oxygen saturation to fraction of inspired oxygen divided by respiratory rate. A higher ROX Index reflects better oxygenation efficiency and lower respiratory effort.

Clinically, a ROX Index greater than 4.88 measured after initiation of high flow nasal cannula has been associated with lower risk of intubation. This index assists clinicians in early identification of patients who may fail noninvasive oxygen therapy and require escalation of respiratory support. Reference Roca O, et al.

An Index Combining Respiratory Rate and Oxygenation to Predict Outcome of Nasal High Flow Therapy. American Journal of Respiratory and Critical Care Medicine. 2019;199:1368 1376