A retrospective observational study of utility of nonrebreathing mask in moderate to severe hypoxemic COVID-19 pneumonia

Abstract

Introduction: The pulmonary manifestations of covid-19 disease may range from mild pneumonia to severe acute respiratory distress syndrome (ARDS) complicated by shock or multiorgan failure. Proper selection and utilization of oxygen delivery system is the key factor in treating the hypoxemic respiratory failure in severe covid-19 disease. Here by, we present a retrospective observational study of utility of NRBM (Non Rebreathing Mask) in 1876 moderate to severe hypoxemic Covid-19 pneumonia patients in a single centre and its outcome. Objectives: To study the utility of NRBM in moderate to severe hypoxemic COVID-19 pneumonia Patients. Material and Methods: This was a single centre retrospective observational study. Out of 5024 microbiologically confirmed (by Rapid antigen test/RTPCR/TRUENAT) covid-19 pneumonia patients admitted since September, 2020 to May 2021,1876 patients of age >14 years admitted in the department of Respiratory medicine with moderate to severe hypoxemia (SpO2 90% (corresponds to Pao2 >60 mmhg), respiratory rate (<16/min) and heart rate <100 bpm. About 9.3% of the patients (173) who were provided NRBM support who further deteriorated or showed poor response even after maximum period of 7 days were provided with NIV support (130 patients i.e. 6.92%), HFNC support (14 patients i.e. 0.74%) and invasive mechanical ventilation (29 patients i.e. 1.54%).66 patients who were initially provided NRBM support, recovered and 107 patients (2.129%) succumbed to their illness. smoking (table-4)has been observed to be the major risk factor in majority of the patients (43.7%). As per the data of this study there is significant correlation between the utilization of NRBM and advanced age, early initiation of NRBM rather than directly initiating NIV/HFNC/Invasive mechanical ventilation and duration of presentation to the hospital with symptoms. Smokers were observed to be associated with more severe presentation and longer time for weaning. Hypertension and Diabetes were observed to most commonly associated comorbidities in the study population. Hypoxemic covid-19 patients who were provided NRBM support were having better outcome and reduced mortality risk compared to patients who were provided NIV/HFNC/Invasive mechanical ventilation. Conclusion: In reference to the results in our study, we recommend the use of NRBM in moderate to severe hypoxemic patients of covid-19 disease at the early course of the disease.

Keywords

• covid-19 pneumonia
• hypoxemia
• nonrebreathing mask
• oxygen supplementing devices