PREDICTING OUTCOMES IN COVID-19 PNEUMONIA WITH ACUTE RESPIRATORY FAILURE USING THE RESPIRATORY RATE-OXYGENATION INDEX

Abstract

TOPIC: Critical Care TYPE: Original Investigations PURPOSE: Among the various indices of oxygenation, Respiratory Rate-Oxygenation Index (ROX), defined as the ratio of oxygen saturation and fractional percentage of inspired oxygen (SpO2/FiO2) to respiratory rate (RR), has been found to be a predictor of improvement with High-Flow Nasal Oxygen (HFNO) therapy. Limited information exists on utility of ROX in predicting outcome in coronavirus-19 (COVID-19) pneumonia. The objective of this study was to evaluate the ROX index at admission, ROX index at the patient’s lowest oxygen saturation (SaO2) levels and ROX index at Intensive Care Unit (ICU) admission as a marker of outcomes including need for invasive mechanical ventilation (InvMV), hospital length of stay (LOS), ICU LOS and mortality in patients with COVID-19 pneumonia with acute respiratory failure. METHODS: Records of one hundred and five (105) patients admitted to our hospital with COVID-19 pneumonia and acute respiratory failure were reviewed. The following data was obtained: Age, gender; ROX index at admission, at patient’s lowest SaO2 levels, and at ICU admission; need for InvMV, hospital LOS, ICU LOS and number of patients. Pearson’s correlation analysis was used to determine the impact of ROX Index at hospital admission, ICU admission and at lowest SaO2 respectively versus need for InvMV, hospital LOS, ICU LOS and mortality. p≤ 0.05 was considered statistically significant. RESULTS: Seventy-one (71) patients were male (67%)and mean age was 66.5 ± 16.75 years. Mean admission ROX index at admission was 13.46 ± 7.12; mean ROX index at patient’s lowest SaO2 was 6.92 ± 4.98; mean ICU admission ROX was 6.47 ± 6.43. Twenty-five patients (23.8%) required InvMV; the mean hospital LOS was 11 ± 8.91 days, the mean ICU LOS was 4.39 ± 8.26 days, and thirty-three patients (31.4%) expired. Pearson’s correlation analysis demonstrated the following: ROX index at Admission Need for invasive MV (p<0.001, r= -0.03) Hospital LOS (p=0.02, r= -0.222) ICU LOS (p<0.001, r= -0.383) Mortality (p=0.018, r= 0.234) ROX index at Lowest SaO2 Need for invasive MV (p<0.001, r= -0.347) Hospital LOS (p<0.001, r= -0.395) ICU LOS (p<0.001, r= -0.322) Mortality (p=0.014, r= 0.23) ROX index at ICU admission Need for invasive MV (p=0.022, r= -0.358) Hospital LOS (p=0.02, r= -0.36) ICU LOS p=0.08, r= -0.272) Mortality (p=0.17, r= 0.215) CONCLUSIONS: ROX index at admission and at patient’s lowest SaO2 is associated with increased need for InvMV, increased hospital LOS, ICU LOS and mortality. ROX index at ICU admission was also associated with increased need for InvMV and hospital LOS but did not show statistically significant correlation with ICU LOS and mortality. CLINICAL IMPLICATIONS: ROX index can be used to predict need for InvMV and mortality in patients with COVID-19. Further studies are required to delineate if there is a specific value that can predict need for InvMV and mortality. DISCLOSURES: No relevant relationships by Debapriya Datta, source=Web Response No relevant relationships by Manasvi Gupta, source=Web Response No relevant relationships by Gaurav Manek, source=Web Response No relevant relationships by Suong Nguyen, source=Web Response