CPAP Better Than HFNO and Conventional Oxygen for COVID-19 Acute Respiratory Failure

By Megan Brooks

August 11, 2021

NEW YORK (Reuters Health) - For adults hospitalized with acute respiratory failure due to COVID-19, continuous positive airway pressure (CPAP), but not high-flow nasal oxygenation (HFNO), reduces the likelihood of needing tracheal intubation, compared with standard oxygen therapy, according to results of the Recovery-RS trial.

The results were posted on medRxiv ahead of peer review and simultaneously presented at the Critical Care Reviews conference.

CPAP and HFNO have been recommended for acute respiratory failure related to COVID-19. However, questions remain regarding effectiveness and safety.

Until now, "there has been no definitive data to tell us which is the most effective treatment," co-chief investigator Dr. Gavin Perkins of Warwick Medical School, University of Warwick, in the U.K., said during a press briefing.

The RECOVERY-RS trial was an adaptive, multicenter, randomized controlled trial comparing CPAP with HFNO, and both against standard oxygen therapy, in 1,272 adults hospitalized with acute respiratory failure due to COVID-19; 380 patients received CPAP, 417 received HFNO and 475 received conventional oxygen therapy.

Compared with conventional oxygen, fewer patients in the CPAP group required tracheal intubation or died within 30 days, the primary outcome (36.3% vs. 44.4%; unadjusted odds ratio, 0.72; 95% confidence interval, 0.53 to 0.96).

In contrast, HFNO provided no benefit over conventional oxygen therapy in the primary outcome (44.4% vs. 45.1%; unadjusted OR, 0.97; 95% CI, 0.73 to 1.29).

The "major driver" of CPAP is avoiding the need for invasive ventilation. "If you treated 12 patients with CPAP, you avoid one patient needing invasive ventilation so quite an important finding," co-chief investigator Dr. Danny McAuley with Royal Victoria Hospital and Queen's University Belfast told the briefing.

Neither HFNO nor CPAP significantly reduced mortality, compared with conventional oxygen therapy.

On secondary outcomes, CPAP compared with conventional oxygen therapy also reduced the need for admission to critical care and also prolonged the time to intubation, "which reduces the impact on critical care resources," Dr. McAuley said.

A limitation of the trial is the failure to achieve the planned sample size when the decision was made to stop recruitment due to practical reasons around falling numbers of COVID-19 cases in the U.K., and an ethical obligation to quickly share the accumulated data, the researchers note.

There was also crossover between allocated treatment groups, largely from the conventional oxygen therapy group to the CPAP or HFNO group. "This is a common challenge in trials of non-invasive respiratory strategies, and reduces the observed effect size of a clinically effective treatment," the researchers write in their paper.

In addition, they note that the trial was rapidly set up early in the pandemic, before the development of a core outcome set for COVID-19 trials. "Whilst our outcome list aligns closely to most of the core outcomes subsequently identified, we did not capture information on patient recovery following hospital discharge," they note.

In a statement (, Dr. Nick Lemoine, medical director at the National Institute for Health Research (NIHR) Clinical Research Network, said, "Preliminary results from this NIHR-supported trial provide important evidence which will help shape clinical practice worldwide around respiratory support interventions for hospitalized COVID-19 patients."

"The study will undoubtedly help improve outcomes for patients, while potentially alleviating pressure on hospital beds and critical care services," said Dr. Lemoine.

This study was funded by the National Institute for Health Research. The authors have no relevant disclosures.

SOURCE: medRxiv/Critical Care Reviews Conference, online August 5, 2021.


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