High-flow nasal cannula oxygen compared with standard oxygen therapy not associated with significant reduction in mortality in patients with respiratory failure due to COVID-19 – The SOHO-COVID Randomized Clinical Trial

1. In this randomized controlled trial, among 711 patients with respiratory failure due to COVID-19, mortality at day 28 was 10% in the high-flow oxygen group and 11% in the standard oxygen therapy group.

2. The intubation rate was significantly lower with high-flow oxygen (45%) than with standard oxygen (53%).

Evidence Rating Level: 1 (Excellent)

Study Rundown: Over 6 million deaths around the world have occurred due to acute hypoxemic respiratory failure due to COVID-19. Standard oxygen has been used as first-line therapy for up to 80% of hospitalized patients, and 45% of patients admitted to the intensive care unit (ICU). With the aim of avoiding intubation in patients with respiratory failure due to COVID-19, high-flow nasal cannula oxygen has been proposed as a noninvasive oxygenation support treatment. The objective of this study was to determine whether high-flow oxygen therapy, compared with standard oxygen therapy, could reduce the rate of 28-day mortality in patients admitted to the ICU with respiratory failure due to COVID-19. Patients were randomly assigned to receive either high-flow oxygen (n=357) or standard oxygen (n=354). The main outcome was mortality at day 28, and secondary outcomes included the proportion of patients requiring intubation, number of ventilator-free days at day 28, 90-day mortality, length of stay in the ICU and adverse events. The mortality rate at day 28 was found to be 10% in patients receiving high-flow oxygen and 11% in patients receiving standard oxygen, a difference that was not statistically significant. Most (12 out of 13) of the secondary outcomes showed no significant difference between the intervention groups. However, the intubation rate was found to be significantly lower in the high-flow oxygen group compared to the standard oxygen group. The most common adverse events in the high-flow oxygen group and the standard oxygen group were ventilatory-associated pneumonia, with an occurrence rate of 58% and 53%, respectively. A major strength of this study was its large-scale and well-defined study protocol. While results of this trial may be generalized to patients admitted for respiratory failure due to COVID-19 in ICUs across the world, a limitation to this study was that results may not be fully generalizable to acute hypoxemic respiratory failure due to other causes.

Click to read the study in JAMA

Click to read an accompanying editorial in JAMA

Relevant Reading: High flow nasal oxygen therapy to avoid invasive mechanical ventilation in SARS-CoV-2 pneumonia: a retrospective study

In-Depth [randomized controlled trial]: This study investigated whether the use of high-flow oxygen, compared with standard oxygen therapy, was associated with a reduction in the 28-day mortality rate of patients with respiratory failure due to COVID-19. A total of 711 patients with respiratory failure due to COVID-19, admitted across 34 ICUs in France between January to December 2021, were included in this analysis. Patients were randomly assigned to receive either high-flow oxygen (n=357) or standard oxygen delivered through a nonrebreathing mask (n=354). The main outcome of this study was mortality at day 28, and some of the secondary outcomes included intubation rate by day 28, number of ventilator-free days at day 28, mortality at 90 days and mortality rate in the ICU. The mortality rate at day 28 was 10% (36 of 357 patients) in the high-flow oxygen group and 11% (40 of 354) in the standard oxygen group (absolute difference, -1.2% [95% CI, -5.8 to 3.4%]; P =.60). The hazard ratio for mortality at day 28 was 0.88 (95% CI, 0.56 to 1.38; P = .57) in the high-flow oxygen group compared with the standard oxygen group. Intubation rate by day 28 was a secondary outcome, and was found to be 45% (160 of 357 patients) in the high-flow group, and 53% (186 of 354) in the standard oxygen group (absolute difference, -7.7% [95% CI, -14.9% to -0.4%]; P = .04; hazard ratio, 0.77 [95% CI, 0.63 to 0.96]; P = .03 by log-rank test). The median number of ventilator-free days at day 28 was 28 days (IQR, 11 to 28) in the high-flow oxygen group, and 23 days (IQR, 10 to 28) in the standard oxygen group (absolute difference, 0.5 days [95% CI, -7.7 to 9.1]; P = .07). There was no significant difference in mortality at 90 days found between the two groups (13% [48 of 357 patients] vs 15% [53 of 354]; absolute difference, -1.5% [95% CI, -6.7% to 3.6%] in the high-flow oxygen group vs the standard oxygen group, respectively; P = .56). Mortality rate in the ICU also had no significant difference between the high-flow oxygen group and the standard oxygen group (12% [42 of 357 patients] vs 15% [52 of 354]; absolute difference, -2.9% [95% CI, -7.9% to 2.1%]; P = .25), respectively.

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