A useful solution for the management of COVID-19 pneumonia has been identified: oxygen therapy delivered using a high-flow nasal cannula (HFNC). Improved oxygenation and respiratory support are provided by this treatment. In patients who are being associated with HFNC for COVID-19 pandemic, this investigation aims to define whether or not the respiratory rate index (RRI) is useful as an early indicator of how well the treatment is working and how the patient would fare clinically. This study retrospectively examines COVID-19 pneumonia patients maintained with HFNC in a clinical setting. Data on respiratory rate (RR) was used to calculate a respiratory rate index that considered both rate and pattern. Fast respiratory rate index reductions during the first therapy improved oxygenation and reduced mechanical ventilation. The score predicted pharmaceutical responsiveness before other clinical markers made meaningful improvements. RR, OSIXR, and ROX index are questionable ventilator prevention strategies. We treated 128 COVID-19 respiratory failure patients who needed oxygen. A 64 HFNC-treated patients were retrospectively studied. The HFNC group was those who converted from the HFNC therapy to conventional oxygen therapy (COT), while the COT treatment was those who converted from the HFNC group to Non-invasive ventilation (NIV). HFNC patients were successful (24 of 64 (62%)). HFNC success had a considerably greater univariate RR improvement than COT. Logistic regression analysis (LRA) adjusted for respiratory development, age, and ROX index >6.66 showed that an enhanced RR predicted success. HFNC achievement groups had significantly lower COT durations than COT groups.