A retrospective observational study to determine the role of High Flow Nasal Oxygen in terms of recovery, mortality and need for invasive ventilation in COVID-19 cases

Abstract

Background: Hypoxemic respiratory failure in COVID-19 is managed by conventional oxygen, High Flow Nasal Oxygen (HFNO), and invasive ventilation. Multiple studies have proven that using HFNO in the early stages of acute hypoxemia failure can lead to better outcomes and delay or avoidance of invasive ventilation. This observational study was conducted to further establish this hypothesis. Also, no difference was found in mortality rates between the usage of HFNO Conventional Oxygen Therapy. However, there are very limited studies comparing outcomes of HFNO and Invasive ventilation usage. Hence, this study was undertaken to gain insight into comparing HFNO and invasive ventilation. Materials and Methods: A retrospective data collection was performed from 06/05/2021 to 15/12/2021 after approval from the Institutional Ethics Committee. The collection was performed at MMFHA Ratna Hospital, Pune. All Indoor patient department files of positive cases of COVID first wave (2020) and second wave (2021) were screened. Reverse Transcription Polymerase Chain Reaction COVID-positive cases belonging to both genders, aged 18-100 years and where HFNO was part of management were selected, and data was extracted about socio-demographic data, clinical profile, and routine investigations advised, course of the patient in the hospital with respect to vital parameters, daily HFNO parameters, all the medications received, any other interventions if required, and the time points of taking patients off HFNO, the requirement of invasive ventilation, shifting out of Intensive Care Unit discharge, or death. Immunocompromised cancer patients and pregnant women were excluded. Outcomes were measured in terms of recovery, need for mechanical ventilation, and mortality. Results: Out of 700 cases screened, HFNO was used in 38 (5.4%) participants. The duration of HFNO ranged from less than one day to more than seven days. Of those 38, 30 (78.9%) received HFNO and 8 (21.05%) were shifted to mechanical ventilation. Out of these 30, eight (21.05%) expired on HFNO, eighteen (47.36%) were discharged, and four (10.52%) were shifted to another hospital on HFNO. All eight participants on mechanical invasive ventilation expired. Conclusions: In terms of recovery from HFNO use, discharge with a recovery rate was higher than mortality and the need for mechanical ventilation. The need for invasive mechanical ventilation was much lower in HFNO used participants (26 versus 8). All those on mechanical ventilation expired. HFNO can be a useful modality for oxygenation in COVID-19 patients. The exact role of HFNO in the trajectory of the management of hypoxemic respiratory failure due to COVID-19 needs to be defined.