May 17, 2022
High-flow nasal oxygen versus conventional oxygen therapy in patients with COVID-19 pneumonia and mild hypoxaemia: a randomised controlled trial.
What was the research question?
Does the use of high-flow nasal oxygen (HFNO) improve clinical outcomes in hospitalized patients with COVD-19 pneumonia and mild hypoxemia compared to conventional oxygen therapy (COT) in terms of preventing escalation of respiratory support?
How did they do it?
A multicenter, randomized, parallel-group, open-label trial at 27 centres in 6 countries (Italy, Greece, Spain, Portugal, Poland, Turkey).
362 patients with COVID-19 pneumonia and peripheral oxygen saturation (SpO2) ≤92% who required oxygen therapy or arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) ratio 200-300 were randomized to receive HFNO (181 patients) or COT (181patients).
The primary outcome was the rate of escalation of respiratory support (ie, continuous positive airway pressure, non-invasive ventilation or invasive mechanical ventilation) within 28 days.
Secondary outcomes included clinical recovery (SpO2 ≥96% with fractional inspired oxygen (FiO2) ≤30% or partial pressure of arterial carbon dioxide/FiO2 ratio >300 mm Hg).
What did they find?
There was no significant difference in the rate of escalation of respiratory support between the HFNO group and the COT group (30.3% vs. 38.6%, p=0.09).
There was no significant difference between the HFNO group and the COT group in clinical recovery (69.1% vs 60.8%), intensive care unit admission (7.7% vs 11.0%), and hospital length of stay (11 vs, 11) days.
Are there any limitations?
Not blinded and the subjectivity in clinical judgment cannot be excluded (physician may consider HFNO a form of advanced support and may not have escalated support).
The study is underpowered as the event rate was lower than expected (40% vs 55%).
What does it mean?
The use of HFNO did not significantly reduce the likelihood of escalation of respiratory support in patients with COVID-19 pneumonia and mild hypoxaemia. However the study is underpowered and clinically meaningful benefit from HFNO in this patient population could not be definitely ruled out.