CPAP reduces need for 30-day intubation in COVID patients, but not mortality 'unsettling' study finds

The use of continuous positive airway pressure (CPAP) reduces the need for 30-day tracheal intubation in hospitalized COVID19 patients, but not mortality. Findings come from the anticipated RECOVERY-RS trial, with results published in JAMA. The study examined the effects of initial noninvasive respiratory strategies using CPAP or high-flow nasal oxygen (HFNO), compared to conventional oxygen therapy, on the risk of tracheal intubation or mortality within 30 days. A common complication of advanced COVID-19 is acute hypoxemic respiratory insufficiency which requires oxygen and ventilation therapies, according to study co-author Dr. Danny McAuley, professor of medicine at the University of Warwick. Many patients may need to switch between non-invasive and invasive devices, depending on the severity of their respiratory symptoms. Read: QUIZ: Test your knowledge of obstructive sleep apnea “But determining the most effective form of ventilatory support for patients with COVID-19 is vital to ensure optimum therapy is delivered to patients,” he said. There is a lack of data on using either HFNO or CPAP directly in patients with COVID-19—although a number of trials have investigated their use in patients with acute respiratory failure (ARF). The study was a parallel group, randomized clinical trial of hospitalized adults with COVID-19-related acute hypoxemic respiratory failure. Patients were enrolled between April 6, 2020, and May 3, 2021, across 48 acute care hospitals across the UK and Jersey. Final follow-up was conducted in June 2021. The primary outcome was a composite of tracheal intubation or mortality within 30 days. The study included 1,273 patients, with a mean age of 57.4 years, 66.3% were male and 65.3 were Caucasian. They had a median time from first COVID-19 symptoms to randomization of nine days, and had a median pulse oximetry of 93% at baseline. Over a third, 380 patients, were started with CPAP; 418 with HFNO, and 475 were in the conventional oxygen therapy group. Patients in the CPAP or HFNO groups began treatment as soon as possible, and breaks were allowed for comfort. The patients who received conventional oxygen therapy received oxygen through a standard face mask from a low-flow nasal cannula. Of the participants, 733 (377) in the CPAP group and 356 in the conventional oxygen therapy group were included in the comparison of CPAP with conventional oxygen therapy. A total of 783 of the patients were included in the comparison of HFNO with conventional oxygen therapy—415 in the HFNO group and 368 in the conventional oxygen therapy group. Read: Refresher on rhinitis and the conditions that mimic it The study stated that for the comparison of CPAP with conventional oxygen therapy, the primary composite outcome (tracheal intubation or mortality within 30 days) occurred in 36.3% of the participants in the CPAP group compared to 44.4% of the patients in the conventional oxygen therapy group. Tracheal intubation or mortality occurred in 44.3% of the HFNO patients, and 45.1% of the participants in the conventional oxygen therapy group. It was also found that the time to tracheal intubation tended to be longer in the CPAP group. But when analyses were done to look at intubation and mortality separately, there was no significant difference in 30-day mortality. When “compared with conventional oxygen therapy, neither CPAP nor HFNO significantly reduced mortality in the ICU or in the hospital,” the study said. “The main message for the clinician is that for patients with COVID with increasing oxygen requirements, an initial strategy using CPAP should be the treatment of choice,” Dr. McAuley told The Medical Post in an email. Read: Study shows risks for COPD varies across Canada When it came to adverse events (AEs), they were more common in the CPAP group. AEs occurred in in 34.2% of the CPAP group; 20.6% of the HFNO group, and 13.9% of the patients who got conventional oxygen therapy. Findings are “unsettling” An accompanying editorial in JAMA by researchers in Brazil described the finding that noninvasive ventilation did not reduce mortality as “unsettling”. It added that “the interpretation of a reduction in tracheal intubation without a reduction in mortality can be challenging.” It was possible that the patients not getting tracheal intubation had less severe illness. Another take was from Dr. Alan Kaplan, a lecturer in the faculty of medicine at the University of Toronto, who said he didn’t find the results surprising. He was not involved in the study. “COVID lung is associated with interstitial changes, lung thickening and then scarring, so oxygen going in passively will only go so far, the oxygen needs to be pushed through the thickened lung tissues to get into the alveoli and capillaries where gas exchange occurs,” he said. Dr. Kaplan is also chair of the Family Physicians Airways Group. Read: Association between asthma and autoimmune disorder myasthenia gravis: meta-analysis The lack of effect on mortality could be related to two key things. One is that there could be a delay in intubating the patients who will need it—they work (breathing-wise) at a disadvantage potentially for longer which could contribute to more damage. Also, CPAP might be more effective in milder patients. “It has been shown that nursing in a prone position improves COVID recovery, which is hard to do with CPAP frankly. But when patients are intubated and have a bit of sedation, that position can be maintained,” he said. The study offers “a small piece of the puzzle for those that do develop more severe illness,” Dr. Kaplan said.

CPAP reduces need for 30-day intubation in COVID patients, but not mortality 'unsettling' study finds

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