Treating coronavirus hospital patients who have acute respiratory failure with continuous positive airway pressure (CPAP) reduces the need for invasive mechanical ventilation, new research suggests.

Preliminary data from the study also indicates the routine use of high-flow nasal oxygenation (HFNO) should be reconsidered, as it did not improve outcomes for Covid-19 patients compared with conventional oxygen therapy.

Researchers suggest their findings can help reduce pressure on intensive care units.

The Respiratory Strategies in Covid-19, CPAP, High-flow, and Standard Care (Recovery-RS) trial, led by the University of Warwick and Queen’s University Belfast, is the world’s largest non-invasive respiratory support trial for Covid-19.

More than 1,200 participants took part across 48 UK hospitals.

What this trial does, for the first time, is provide an evidence base that can give patients, their families and clinicians, the confidence to step from controlled oxygen therapy to CPAP

Gavin Perkins, chief investigator and professor in critical care medicine at Warwick Medical School at the University of Warwick, said: “The routine use of high-flow nasal oxygenation, which can consume large amounts of oxygen, should be reconsidered as it did not improve outcomes.

“By giving patients the most effective treatment to begin with, we can help prevent resource shortages in our NHS and make sure the right type of ventilation is available to patients when it is required.

“This is the first large trial of different types of ventilation in Covid-19. While it is encouraging that these results can help reduce the number of people who require invasive ventilation, it is important to stress that, where it is needed, invasive ventilation can be lifesaving.”

He added: “What this trial does, for the first time, is provide an evidence base that can give patients, their families and clinicians, the confidence to step from controlled oxygen therapy to CPAP, knowing that for one in 12 people that that therapy is provided will escape the need for invasive ventilation.”

Researchers compared the use of CPAP (oxygen and positive pressure delivered via a tightly fitting mask), with HFNO (high pressure oxygen delivered up the nose), against standard care (standard oxygen therapy).

All three methods are commonly used to treat Covid patients before they are moved on to invasive ventilation in a critical care bed.

But it was not known which, if any, resulted in a better outcome.

Between April 2020 and May 2021, 1,272 Covid-19 patients admitted to hospital with acute respiratory failure, aged over the age of 18, were recruited to the study.

They were randomly allocated to receive one of the three respiratory support interventions as part of their hospital care.

Some 380 (29.9%) participants received CPAP, 417 (32.8%) participants received HFNO, and 475 (37.3%) received conventional oxygen therapy.

In the comparison of CPAP and conventional oxygen therapy, the likelihood of patients going on to require invasive mechanical ventilation or die within 30-days of treatment was significantly lower in those who were treated with CPAP, than those who received standard care.

In the CPAP group, 137 of 377 participants (36.3%) either needed mechanical ventilation or died within 30 days, compared with 158 of 356 participants (44.4%) in the conventional oxygen therapy group.

The study, which has been released as a pre-print and has not yet been peer-reviewed, found that there was no difference between patients in the HFNO and conventional oxygen therapy groups.

Based on these results, one person would avoid needing invasive ventilation within intensive care units (ICU) for every 12 people treated with CPAP instead of standard oxygen therapy, the researchers say.

Danny McAuley, chief investigator and professor and consultant in intensive care medicine at the Royal Victoria Hospital and Queen’s University Belfast, said: “The results of this trial are really encouraging as they have shown that by using CPAP, invasive ventilation may not be needed for many patients with Covid-19 requiring high oxygen levels.

“Avoiding invasive ventilation is not only better for the patients, but it also has important resource implications as it frees up ICU capacity.

“This research should help healthcare professionals in the UK and beyond manage patients with Covid-19, to improve patient outcomes while helping to lessen the burden on resources.”

Professor Jonathan Van-Tam, deputy chief medical officer, said: “This study, funded by the NIHR, provides valuable evidence around how non-invasive respiratory support can be used to improve patient outcomes.

“Reducing invasive mechanical ventilation is better for patients and reduces pressures on mechanical ventilator capacity across the NHS.”