Prone positioning may benefit some patients with COVID-19 respiratory failure

Use of prone positioning is feasible and may yield improvements in some patients with COVID-19 who are receiving noninvasive respiratory support, according to two research letters published in JAMA.

High tolerance of prone positioning

In the first study, researchers evaluated a series of patients with COVID-19 who were awake, nonintubated and spontaneously breathing but required oxygen supplementation due to hypoxemic acute respiratory failure at the Aix-en-Provence Hospital in France from March 27 to April 8. Patients were followed for up to 10 days through April 28.

Of the 24 patients included in the study, 15 tolerated prone positioning for more than 3 hours, five tolerated it for 1 to 3 hours and four did not tolerate it for more than 1 hour. Six patients, representing 25% of all patients and 40% of those who tolerated prone positioning for at least 3 hours, demonstrated an at least 20% increase in partial pressure of arterial oxygen (PaO2) from before to during prone positioning.

Also among those who tolerated prone positioning for at least 3 hours, the researchers noted an increase in PaO2 from 73.6 mm Hg before prone positioning to 94.9 mm Hg after prone positioning (difference, 21.3; P = .006). However, they found no difference between PaO2 before prone positioning and after resupination (P = .53).

Five patients required invasive mechanical ventilation, including four who tolerated prone positioning for less than 1 hour and required intubation within 72 hours.

Improvement in respiratory parameters

The second study, conducted at San Raffaele Scientific Institute in Milan on April 2, evaluated 15 patients with COVID-19 and mild to moderate acute respiratory distress syndrome who underwent prone positioning noninvasive ventilation outside of the ICU after poor response to CPAP. They examined respiratory parameters in patients before noninvasive ventilation, during noninvasive ventilation in pronation and 60 minutes after the end of noninvasive ventilation.

Among the patients included in the study, noninvasive ventilation in the prone position began a median of 5 days before April 2 and the median number of cycles was two for a total duration of 3 hours. All patients experienced a reduction in respiratory rate during and after prone positioning (P < .001 for both) as well as an improvement in pulse oximetry (SpO2) and the ratio of PaO2 to fraction of inspired oxygen (PaO2:FiO2) during prone positioning (P < .001 for both).

After prone positioning, 12 patients had an improvement in SpO2 and PaO2:FiO2, two had the same value and one had worsened. Additionally, when compared with baseline, 11 patients also had improvement in comfort during prone positioning and four had the same value while 13 had improvement in comfort after prone positioning and two (13.3%) had the same value.

Nine patients were discharged home, one improved and stopped prone positioning, three continued prone positioning, one underwent intubation and was admitted to the ICU and one patient died at the 14-day follow-up.

Lingering questions

Researchers for both studies acknowledged limitations, such as the small sample sizes and lack of control groups.

In an accompanying editorial, Irene Telias, MD, Bhushan H. Katira, MD, and Laurent Brochard, MD, all from the University of Toronto, placed the findings in context, noting that many patients tolerated prone positioning while awake, breathing spontaneously or receiving noninvasive ventilation, which was accompanied by certain improvements. However, the effects appeared to be transient.

“The prone position during spontaneous and assisted breathing in patients with acute hypoxemic respiratory failure may become a therapeutic invention in the near future,” they wrote, noting that tolerance can be a limitation, the physiological effects are unclear, benefits of short sessions are questionable and physicians approach the decision to intubate with caution after using the prone positioning.

“Improvement in oxygenation during prone positioning may prevent clinicians from making decisions about intubation solely based on hypoxemia. This is potentially a good outcome, but clinical assessment of work of breathing is essential in this context to avoid delayed intubation with eventually poor outcome. A detailed physiological study is ongoing and at least two randomized clinical trials will address some of these questions,” they wrote. “In the meantime, clinicians should closely monitor patients for whom prone positioning is used for tolerance and response and aim to prevent delayed intubation and controlled mechanical ventilation when necessary.”

Disclosures: Elharrar and Sartini report no relevant financial disclosures. Please see the studies for all other authors' financial disclosures. Brochard reports he has received grants from Fisher Paykel and Medtronic Covidien; he has received nonfinancial support from Air Liquide, Philips and SenTec; and he has a patent issued through General Electric. Telias reports she has received personal fees from MBMed SA and Argentina and she has received grants from CIHR, Canada. Katira reports no relevant financial disclosures.