ROX index performance to predict high-flow nasal oxygen outcome in Covid-19 related hypoxemic acute respiratory failure.

"Declarations Ethics approval and consent to participateThe study was approved by the local ethics committee (approval number E2020-40) of the Rouen university hospital. Consent for publicationNot applicable. Competing interestsC.G. declare support for attending meetings and/or travel, grants and non financial support by Fischer & Paykel Healthcare, Resmed Ltd; Equipment and materials for education and training by Fischer & Paykel Healthcare, Resmed Ltd. P.G. declare support for attending meetings and/or travel by Pfizer. S.G. declare payment or honoraria for lectures, manuscript writing or educational events by Alexion and Astra Zeneca; support for attending meetings and/or travel by Alexion, Astra Zeneca, and Sanofi; participation on a data safety monitoring board with Alexion. G.B. declare support for attending meetings and/or travel by MSD. M.B., D.B., P-L.D., G.S., J-B.M., D.C, and F.T. declare that they have no competing interests. Competing interests C.G. declare support for attending meetings and/or travel, grants and non financial support by Fischer & Paykel Healthcare, Resmed Ltd; Equipment and materials for education and training by Fischer & Paykel Healthcare, Resmed Ltd. P.G. declare support for attending meetings and/or travel by Pfizer. S.G. declare payment or honoraria for lectures, manuscript writing or educational events by Alexion and Astra Zeneca; support for attending meetings and/or travel by Alexion, Astra Zeneca, and Sanofi; participation on a data safety monitoring board with Alexion. G.B. declare support for attending meetings and/or travel by MSD. M.B., D.B., P-L.D., G.S., J-B.M., D.C, and F.T. declare that they have no competing interests."

"Funding Not applicable."