Oxygen Metabolism Score Directed Respiratory Support for 2019 Novel Coronavirus Pneumonia

Background: Hypoxemia caused by acute respiratory distress syndrome (ARDS) is a common feature of coronavirus disease 2019 (COVID-19). This study designed and evaluated the oxygen metabolism scoring system (OMSS) to quickly titrate the capability of COVID-19 patients to balance oxygen supply and demand.Methods: Adult patients with confirmed COVID-19 pneumonia were enrolled in this single-centre study and divided into the standard therapy (n=151) and OMSS-directed therapy (n=159) groups according to their admission time. Radiological and laboratory findings, clinical events and outcomes were collected from patients’ medical records. OMSS consisted of four elements with a total score of 10: PaO2 /FiO2, chest imaging, serum lactate and ScvO2, and the scores were given according to the severity of these four parameters. The predictive efficiency of OMSS was validated retrospectively by receiver operating characteristic (ROC) curves.Findings: The areas under ROC curves to predict the execution of conventional oxygen therapy, high-flow nasal cannula oxygen therapy (HFNC), invasive mechanical ventilation (IMV) and extracorporeal membrane oxygenation (ECMO) by OMSS were 0.85, 0.87, 0.97 and 0.99, respectively, and OMSS significantly shortened the time to implement HFNC, IMV and ECMO. Moreover, compared with standard therapy, OMSS-directed therapy resulted in markedly lower proportion of critical patients and organ damage, a shorter duration of IMV and ICU stay. Interpretation: OMSS is an effective screening tool to assess the capability to maintain the balance of oxygen supply and consumption in COVID-19 patients by which physicians can shorten the reaction time to execute rational respiratory support therapies, thus preventing hypoxemia-associated negative events.Funding Statement: This study was supported by the emergency project of Shanghai Science and Technology Commission (20411950200).Declaration of Interests: All authors declare no competing interests.Ethics Approval Statement: The study was approved by the SHPHC Ethics Committee (YJ2020-S028-02) and informed consent was declared exempt from the outbreak of COVID 2019.