Severe COVID-19 pneumonia patients receive oxygen by facemask as primary oxygen therapy. However, patients who develop significant hypoxia may need endotracheal intubation and mechanical ventilation. Early experience shows that patients on invasive mechanical ventilation have very high mortality up to nearly 90% [5]. Therefore, use of less invasive oxygenation devices like High Flow Nasal Oxygen (HFNO) or non-invasive ventilation (NIV) may be a feasible option. In FLORALI trial performed in patients with acute hypoxemic respiratory failure, HFNO reduced 90-day mortality compared to standard oxygen therapy and facemask. Although, intubation rate was not significantly different, there was a trend towards lower intubation rate in HFNO group compared to conventional oxygen and NIV group [6].

Wang et al in their case series had described that four out of 36 critically ill patients (11%) were treated with HFNO [4]. Similarly, in another case series of 191 COVID-19 patients, 41 (21%) were treated with HFNCO (33 in ICU and 8 in non-ICU) [7].  

In an observational series, among 27 patients with severe acute respiratory failure treated with HFNC or NIV, Wang et al reported intubation rate of 11.7% in HFNC patients and 11.1% in NIV patients [8]. 

Based on the initial experience and past data, Surviving sepsis campaign guidelines on the management of critically ill adults with COVID-19 [Ref recommend use of HFNO over NIV [9]. However, data in acute hypoxemic failure due to COVID-19 is too limited to choose between HFNC and NIV so far.