Success of NIV Use in Hypoxic Respiratory Failure in COVID Patients: How Different and Similar Was it To H1N1 Pneumonia?-A Retrospective Study

ABSTRACT

Introduction: Although NIV is a common mode of respiratory support in hypoxic respiratory failure, its use is not adequately supported by literature and guidelines. But in recent times NIV is used extensively in COVID pneumonia patients. Earlier, H1N1 pneumonia group of patients were identified to benefit from use of NIV. But their success in preventing intubation or reducing mortality were not validated by studies. Objective: Our aim was to retrospectively look into the COVID patients admitted to our ICU, observe the outcome benefits of NIV use and compare the difference in outcome benefits of NIV use in the H1NI patients during the previous year. Materials and methods: Retrospective analysis of the COVID pneumonia patients admitted to ICU over one year period in our multi-speciality tertiary care hospital in south India was undertaken. Details were collected from the electronic charting and patient files retrospectively. The data on the usage of non-invasive ventilation as the initial mode of ventilation for hypoxic respiratory failure in these patient groups were analysed. The findings were compared with the data from the H1N1 pandemic patients in 2018 collected from our ICU. The outcome benefit in terms of subsequent invasive ventilation need, mortality and duration of ICU stay were measured. Results of COVID patients Average age of patient was 62.6 years and malefemale ratio was 50%. All patients had associated significant co-morbidities. Average duration of symptom prior to ICU admission was 5.1 days. Length of ICU days was at an average of 6.75 days with 2-18-day variation. 66% had Severe ARDS. In 83% of patients NIV was used and 16% had HFNC and 41% had both NIV and HFNC during the stay. Overall 41% needed invasive ventilation. Only 30% of those who were on NIV went to receive invasive ventilation. Overall mortality was at 41%. Results compared with H1N1 patients 78.6% of H1N1 patients received NIV, of which 42% improved, but 57% needed invasive ventilation when compared to 30% in COVID pneumonia. However, mortality was 36%, which was lower compared to COVID patients. Conclusion: Significant proportion of COVID patients when compared to H1N1 had probably benefited from NIV usage. Whether NIV delayed the needed intubation early is not clear and would it have prevented mortality is not clear either. HFNC is newer mode of Non-Invasive ventilation mode that has gained popularity during the COVID pandemic. There is significant mortality associated with the second wave of COVID pandemic from our experience of treating patients with severe ARDS. Conflict of interest None declared by any of the authors.