Does High-Flow Oxygen Improve Outcomes in COVID Patients?

Use of high-flow oxygen was associated with less of a need for mechanical ventilation and a shorter time to recovery compared with conventional oxygen therapy in patients with severe COVID-19, a randomized trial in Colombia found.

Thirty-four percent of patients randomized to high-flow oxygen through a nasal cannula were intubated by day 28 compared with 51% of those randomized to conventional oxygen therapy (HR 0.62, 95% CI 0.39-0.96, P=0.03), reported Gustavo Ospina-Tascón, MD, PhD, of Fundación Valle del Lili in Colombia, and colleagues in JAMA.

Time to clinical recovery was only 11 days for patients in the high-flow oxygen group versus 14 days for the conventional oxygen group (HR 1.39, 95% CI 1.00-1.92, P=0.047).

“Data suggest that high-flow oxygen therapy might decrease need for endotracheal intubation and risk of escalation of therapy in patients with acute hypoxemic respiratory failure, but with no apparent effect on mortality rates,” the authors wrote.

While most international guidelines recommend high-flow oxygen therapy to treat patients with severe COVID, “evidence supporting this is very limited,” they pointed out.

The High-Flow Nasal Cannula in Severe COVID-19 With Acute Hypoxemic Respiratory Failure (HiFLo-Covid) study was an open-label randomized trial that examined patients in three hospitals in Colombia from August 2020 to January 2021. Adult patients with suspected or confirmed COVID infection, respiratory distress, and “a ratio of partial pressure of arterial oxygen to fraction of inspired oxygen of less than 200 due to COVID-19” were included.

Co-primary outcomes were need for intubation and time to clinical recovery until day 28.

Overall, 220 patients were randomized — 109 to high-flow oxygen therapy and 111 to conventional oxygen therapy, and 199 patients were included in the analysis (median age 60, 32.7% women).

Clinical recovery occurred in 78% of patients in the high-flow oxygen group and 71% of those in the conventional oxygen group.

Patients in the high-flow oxygen group had fewer median ventilator-free days, but with a wide confidence interval (28 vs 24 days; adjusted OR 0.77, 95% CI 0.33-1.68). Need for kidney replacement therapy and length of hospital and ICU stay were similar between groups, and the hazard ratio for death by day 28 was 0.49 (95% CI 0.21-1.16, P=0.11) in the high-flow oxygen therapy group compared with the conventional oxygen therapy group.

In addition to preserving resources, use of non-invasive ventilation for COVID patients could “prevent complications related to invasive mechanical ventilation, sedation, delirium, and neuromuscular paralysis,” Ospina-Tascón and team wrote.

Limitations to the data included lack of blinding due to the trial’s open-label nature, a lack of generalizability of the results since patients were only from three hospitals in one country, and that co-primary endpoints could raise the potential for type 1 error.