A retrospective observational study on the use of rescue niv in severe COVID-19 patients with HFNC treatment failure

Introduction: As the COVID-19 pandemic is progressing, there are drastic efforts around the world for a magic bullet for its treatment, but what we often forget is the supportive treatment that goes a long way in preventing the disease progression Of these the most important are the respiratory supportive measures, which include a spectrum ranging from conventional oxygen therapy to invasive mechanical ventilation As the mortality rates in patients put on mechanical ventilation are very high, it is the noninvasive modes that are proving as the real lifesavers HFNC and NIV are currently the most preferred modes The present evidence shows some mortality benefit while using HFNC but not with NIV in acute hypoxic respiratory failure following any kind of pneumonia 1-3 Objectives: The main objective of the study was to find the usefulness of giving rescue NIV trial in severe COVID-19 patients with HFNC failure Materials and methods: We conducted a retrospective observational study on severe COVID-19 patients admitted to our COVID ICU, who had received oxygen support via HFNC over a period of 9 months (from March 23 to December 23, 2020) After getting institutional ethics committee clearance, from the hospital's electronic database details of all the severe COVID- 19 patients who were admitted to the COVID ICU during the study period were taken Out of this, all those who were given HFNC support were observed for the primary and secondary outcome measures We excluded all the patients <18 years, patients who had taken discharge against medical advice, and patients who were still admitted with us and had not achieved the primary outcome (intubation or mechanical ventilation) As a secondary outcome, we also measured the HFNC failure rate (defined as the need for the application of rescue NIV trial) and mortality rate in the intubated patients The routine hospital treatment protocol for treating COVID-19 was followed during the study duration, which includes the application of HFNC in all severe disease with type 1 respiratory failure who were not tolerating conventional O2 therapy Those who had the features of HFNC failure were then given an NIV trial before proceeding with any invasive treatment If tolerating the same, this was followed by alternate HFNC and NIV application titrated to the patient's respiratory distress Results: Of the total 595 COVID hospital admissions, 265 of the severe COVID- 19 patients were admitted to the ICU during the study duration Out of them, 85 needed HFNC support The average age of the patients was 56 years (32-80 years) and 80% of them were male The HFNC failure rate was observed to be 28/85(32 9%) Out of this 10 were successively managed with rescue NIV trial and the remaining 18 had to intubated Out of the intubated patients 14 died at the hospital, 2 of them were discharged against medical advice and 2 of them were successfully extubated and discharged Discussions: The intubation rate (21 2%) in our cohort of patients who were given HFNC support was significantly lower than those observed in other major studies like the FLORALI study (38%), where it was used for managing acute hypoxic respiratory failure (in which 84% of them had one or other kind of pneumonia) 3 Even though the HFNC failure rate was 32 9%, by using NIV as a rescue device, intubation was prevented in 11 8% of the patients The implications of the above finding are vast since the mortality of the intubated COVID-19 patients are very high across the world and a significant decrease in intubation rates means more life's saved In our study population also, 14 (77%) of the patients who were intubated following HFNC failure died Conclusion: On giving a rescue NIV trail followed by its intermittent application with HFNC, the intubation rates in hypoxic respiratory failure following severe COVID-19 shows a decreasing trend The above finding needs to be further explored with controlled trials