Awake prone position has been widely used in COVID-19 patients with respiratory failure and incorporated in clinical guidelines and consensus statements. However, high level evidence is lacking and most recommendations were based on anecdotal data, observational and retrospective small studies.
The authors of this study (1) were able to combine six international open-label randomized trials from France, Mexico, Canada, USA, Spain, and Ireland in one meta-trial of COVID-19 patients with respiratory failure requiring high flow nasal cannula with SpO2/FiO2 of ≤ 315 (equivalent to PaO2/FiO2 ≤ 300). Patients were assigned to awake prone position during the day as long as tolerated compared to standard care. The primary composite outcome was treatment failure defined as intubation OR death within 28 days of enrolment.
The study revealed that awake prone position was associated with a lower treatment failure (40%) compared to 46% in the standard group in a total of 1126 patients included in the study. When looking at the individual components of the composite primary outcome measure, mortality was not different between the two groups and the main effect was on the need of intubation. The study results were most remarkable among patients who remained in prone position for at least 8 hours. Treatment failure in these patients occurred in 25 out 151 patients (17%) compared to 198 out of 413 patients (48%) who remained in prone position of less than 8 hours. Of note, most of these longer duration proning occurred in Mexico.
This study is not without limitations. First, it is an open-label trial due to the nature of the intervention which may have caused some bias among the investigators. However the duration of mechanical ventilation and the mortality of those patients who were intubated were similar in the two groups indicating that physicians were probably not influenced with randomization choice. The second limitation is that almost 10% of the patients in the standard of care group underwent awake prone position that may have underestimate of efficacy of the intervention. Lastly, this meta-trial lacks a unified protocol among all the individual trials in the study which may have caused some issues such as differences in inclusion criteria or difficulty in tracking enrolment rate.
Nevertheless, the study is powerful enough to indicate a clear patient-centered benefit in implementing this intervention in patients respiratory failure due to COVID-19 who were treated with high flow nasal cannula. An important caveat in mind that proning trials in intubated patients showed a mortality benefit only after the duration was extended to 16 hours or more. It seems that we may have a similar pattern in awake prone position in these patients and we should encourage for longer duration as tolerated by the patient.
I also recommend to review the the editorial on the same article published by J. Weatherald et al (2).
Ehrmann S, Li J, Ibarra-Estrada M et al. Awake prone positioning for COVID-19 acute hypoxaemic respiratory failure: a randomised, controlled, multinational, open-label, meta-trial. Lancet Respir Med.2021.
Jason Weatherald, John Norrie, and Ken Kuljit S Parhar. Awake prone positioning in COVID-19: is tummy time ready for prime time? Published:August 20, 2021DOI:https://doi.org/10.1016/S2213-2600(21)00368-4