ROX Index Predicts Failure of HFNO Therapy in Patients of COVID-19 Pneumonia with Type I Respiratory Failure

Background: In the first half of 2020 COVID-19 disease has already converted into a global pandemic. Various treatment options were being tried all over the world. The ROX index (Respiratory rate – Oxygenation), defined as the ratio of peripheral oxygen saturation and fraction of inspired oxygen, to respiratory rate, is a simple bedside test to predict failure of HFNO Therapy and need for MV. Aim: The aim of the study was to evaluate the accuracy of the ROX index for Predicting the failure of HFNO Therapy and need for Intubation in Patients of COVID-19 Pneumoniawith type I respiratory failure. Methods: An observational study of consecutive patients admitted in ICU of the department of Anesthesiology, critical care and pain management in Govt. Medical college Srinagar (J&K) over the period of six months with moderate tosevere type I respiratory failure treated with High Flow Nasal OxygenTherapy (HFNOT). One hundred and thirty four RT-PCR positive COVID-19 patients were enrolled. The following data were collected: medical history, clinical classification of COVID-19 infection, the ROX index measured daily and the outcome assessment. Results: We performed this observational study on 134RT-PCR positive COVID-19 patients. 70 (52.23%) patients with moderate to severe COVID-19 infection were intubated, 60% of them third day of admission, only 35% patients with moderate COVID-19 infection required intubation. Presence of comorbidities was directly associated with ROX index. At intubation, median (min-max) of ROX and PO2/FiO2 ratio was 4.02 (2.99–5.10) and 88.10 (58–106.15), respectively. ROX 1, 2, 3 indices were significantly as¬sociated with intubation (p < 0.001 for each of them). COVID-19 clinical classification was sig¬nificantly associated with intubation (p < 0.001). Conclusion: ROX index is a valuable, noninvasive tool to evaluate patients with moderate to severehypoxemic respiratory failure in COVID-19 treated with HFNOT. ROX is a simple noninvasive promising