Value of Rox Index to Predict Intubation and Intensive Care Unit Outcome in Patients with Respiratory Failure.

BACKGROUND

Recent literature suggests that the respiratory rate oxygenation (ROX) index may be a useful parameter in predicting intubation indication in hypoxemic patients.

OBJECTIVE

In this study, we evaluated the accuracy of the ROX index in predicting intubation, length of stay in the ICU, and mortality in ICU patients with hypoxemic respiratory failure with and without hypercapnia.

METHODS

Single-centre retrospective cohort study of 290 patients, with a preliminary diagnosis of respiratory failure, who were treated with low flow oxygen systems. Demographics, medical history, clinical, laboratory, treatment, and prognostic data were obtained from the electronic records of the hospital. The ROX index was calculated at the time of ICU admission.

RESULTS

Thirty-seven percent of non-hypercapnic and 69% of hypercapnic patients were intubated (p:0.005). In hypercapnic patients, ROX: 6.9 had highest sensitivity (81%) and specificity (65%) values for intubation (p:0.005). In non-hypercapnic patients, ROX: 6.2 had the highest sensitivity (81%) and specificity (40%) values. While 11% of hypercapnic patients and 30% of non-hypercapnic patients were died (p:0.05), 22% of hypercapnic patients and 33% of non-hypercapnic patients stayed in the ICU longer than 14 days (p:0.044). The highest sensitivity and specificity values were found for mortality in hypercapnic patients; for ROX value of 5.94 (sensitivity:86%, specificity:61%) and for ICU stay longer than 14 days; for ROX value of 7.4 (sensitivity:71%, specificity:68%).

CONCLUSION

Results of our study suggest that ROX index calculated during ICU admission can be helpful in predicting intubation indication and length of ICU stay in patients with respiratory failure and hypercapnia may influence the cutoff values.