ROX index as predictor of high flow nasal cannula therapy success in acute respiratory failure due to SARS-CoV-2

Abstract

Background : High-Flow Nasal Cannula (HFNC) therapy is useful treatment in patients with acute respiratory failure (ARF). The ROX index (ratio of pulse oximetry/fraction of inspired oxygen to respiratory rate) has been evaluated to predict success of HFNC in patients with pneumonia. Objective : The aim of this study was to determine whether the ROX Index could predict HFNC therapy success in patients with ARF due to SARS-CoV-2 pneumonia. Methods : An observational, prospective study was performed including patients admitted with ARF secondary to SARS-CoV-2 pneumonia who met criteria for HFNC therapy initiation. Demographic, radiological, laboratory and clinical course data were collected. The ROX index was calculated at 1 hour, 6 hours, 12 hours and 24 hours after starting HFNC. Results : In total 85 patients were included (age, 64.51+11.78 years; male, 69.4%). HFNC failed in 47 (55.3%) patients, of whom 45 (97.8%) were initially managed with noninvasive ventilation (NIV). ROX index at 24 hours was the best predictor of HFNC success (AUC 0.826, 95%CI 0.593-1.00, p =0.015) with a cut-off point of 5.35 (S 0.91, Sp 0.79, PPV 0.92, NPP 0.79). In multivariate logistic regression analysis ROX index at 24 hours proved the best predictor of HFNC success. Conclusions : ROX index at 24 hours with a cut-off point of 5.35 predicts HFNC success in patients with SARS-Cov-2-induced ARF.

Validity of the ROX index in predicting invasive mechanical ventilation requirement in pneumonia

“…Ferrer et al 26 evaluated the usefulness of the ROX index in patients with a diagnosis of bilateral pneumonia with ARF due to SARS-CoV-2. The findings of the study showed that the ROX index is useful in assessing HFNC use in SARS-CoV-2 pneumonia, with a cut-off point of 5.35, after 24 hours with ventilatory support.…”

High-flow nasal oxygen decrease mortality in patients with severe SARS-CoV-2 pneumonia? Issues and controversies

“…In this regard, different parameters can be used for an accurate evaluation of the levels of severity, such as gas exchange values (PaO2/FiO2) or the ROX index (SO2/FiO2: respiratory rate). A higher ROX index (cut-off point of 5.35) on serial measurement within the first 24 hours of HFNO initiation, predicts the success of therapy in patients suffering from SARS-CoV-2-based pneumonia [ 2 ] while patients with low ROX index are more likely to experience HFNO failure in COVID-19-related respiratory failure [ 3 ].…”

The feasibility of ROX index to predict intubation in patients initiated on high-flow oxygenation

“…In an observational study by Ferrer et al .,[ 4 ] the authors included 85 patients having AHRF due to COVID19 and were initiated on HFNC. The authors observed that HFNC failed in 47 (55.3%) patients.…”