ArticlePloS one2022
ROX index and SpO2/FiO2 ratio for predicting high-flow nasal cannula failure in hypoxemic COVID-19 patients: A multicenter retrospective study.
Article in PloS one, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 27 papers, 1 of them a synthesis that pooled it.
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27 citing papers in PubMed, 1 synthesis or guideline pooled it, 41 citations in OpenAlex.
- Performance of the ROX index in predicting high flow nasal cannula failure in COVID-19 patients: a systematic review and meta-analysis.Critical care (London, England) · 2023Pooled it
- Comparison of HACOR score and ROX index for predicting noninvasive ventilation failure in acute hypoxemic respiratory failure: a prospective study.Irish journal of medical science · 2026Article
- Wave-aware mortality prediction in COVID-19: a multi-stage feature selection and explainable machine-learning framework.BMC medical informatics and decision making · 2026Article
- Prediction of high-flow nasal cannula failure in critically ill patients: a narrative review.Journal of intensive care · 2026Review
- Continuous non-invasive measurement of tidal volume and minute ventilation using a smart nasal cannula.Critical care (London, England) · 2025Article
- Explainable artificial intelligence for predicting cardiovascular events in hospitalised COVID-19 patients.BMC infectious diseases · 2025Article
- Non-invasive SpO2/FiO2 ratio (SFR) as surrogate for PaO2/FiO2 ratio (PFR): A scoping review.Journal of critical care medicine (Universitatea de Medicina si Farmacie din Targu-Mures) · 2025Review
- Triaging acute chest syndrome clinical decision-making using bedside SaO2/FiO2 ratio.Blood advances · 2025Observational
- Unraveling relevant cross-waves pattern drifts in patient-hospital risk factors among hospitalized COVID-19 patients using explainable machine learning methods.BMC infectious diseases · 2025Article
- Prognostic Factors and Clinical Prediction Score for Progressive Respiratory Failure in Severe COVID-19 Pneumonia Patients Treated with Tocilizumab: A Multicenter Study.Therapeutics and clinical risk management · 2025Article
- Association of the ROX index with mortality in sepsis patients: a retrospective study.Frontiers in medicine · 2025Article
- Chlorine gas poisoning by trichloroisocyanuric acid and respiratory failure: a case report of a 49-year-old patient.Frontiers in medicine · 2025Article
- Article
- Efficacy of High Flow Nasal Cannula in the Treatment of Patients with COVID-19 with Acute Respiratory Distress Syndrome: Results of Single Centre Study in Vietnam.Pulmonary therapy · 2024Article
- Oxygenation indices and early prediction of outcome in hypoxemic patients with COVID-19 pneumonia requiring noninvasive respiratory support in pulmonary intermediate care unit.Pneumonia (Nathan Qld.) · 2024Article
- Increased levels of circulating cell-free DNA in COVID-19 patients with respiratory failure.Scientific reports · 2024Article
- Recent advances in cardiorespiratory monitoring in acute respiratory distress syndrome patients.Journal of intensive care · 2024Review
- Respiratory Rate Oxygenation (ROX) index as predictor of high flow nasal cannula in pediatric patients in pediatric intensive care unit.BMC pulmonary medicine · 2024Article
- Reliability of the respiratory rate and oxygenation index for successful high-flow nasal cannula support in coronavirus disease pneumonia: a retrospective cohort study.BMC pulmonary medicine · 2023Article
- [Analysis of ROX Index, ROX-HR Index, and SpOJournal of Korean Academy of Nursing · 2023Article
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Authors and funding
8 authors at 7 institutions in 1 country.
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No grant is acknowledged in the PubMed record.
Abstract
backgroundThe ratio of oxygen saturation (ROX) index, defined as the ratio of oxygen saturation (SpO2)/fraction of inspired oxygen (FiO2) to respiratory rate, can help identify patients with hypoxemic respiratory failure at high risk for intubation following high-flow nasal cannula (HFNC) initiation; however, whether it is effective for predicting intubation in coronavirus disease 2019 (COVID-19) patients receiving HFNC remains unknown. Moreover, the SpO2/FiO2 ratio has been assessed as a prognostic marker for acute hypoxemic respiratory failure. This study aimed to determine the utility of the ROX index and the SpO2/FiO2 ratio as predictors of failure in COVID-19 patients who received HFNC.
methodsThis multicenter study was conducted in seven university-affiliated hospitals in Korea. Data of consecutive hospitalized patients diagnosed with COVID-19 between February 10, 2020 and February 28, 2021 were retrospectively reviewed. We calculated the ROX index and the SpO2/FiO2 ratio at 1 h, 4 h, and 12 h after HFNC initiation. The primary outcome was HFNC failure defined as the need for subsequent intubation despite HFNC application. The receiver operating characteristic curve analysis was used to evaluate discrimination of prediction models for HFNC failure.
resultsOf 1,565 hospitalized COVID-19 patients, 133 who received HFNC were analyzed. Among them, 63 patients (47.4%) were successfully weaned from HFNC, and 70 (52.6%) were intubated. Among patients with HFNC failure, 32 (45.7%) died. The SpO2/FiO2 ratio at 1 h after HFNC initiation was an important predictor of HFNC failure (AUC 0.762 [0.679-0.846]). The AUCs of SpO2/FiO2 ratio at 4 h and ROX indices at 1 h and 4 h were 0.733 (0.640-0.826), 0.697 (0.597-0.798), and 0.682 (0.583-0.781), respectively. Multivariable analysis showed that the patients aged ≥70 years are 3.4 times more likely to experience HFNC failure than those aged <70 years (HR 3.367 [1.358-8.349], p = 0.009). The SpO2/FiO2 ratio (HR 0.983 [0.972-0.994], p = 0.003) at 1 h was significantly associated with HFNC failure.
conclusionsThe SpO2/FiO2 ratio following HFNC initiation was an acceptable predictor of HFNC failure. The SpO2/FiO2 ratio may be a good prognostic marker for predicting intubation in COVID-9 patients receiving HFNC.
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