Skip to main navigation menu Skip to main content Skip to site footer

Original article

Vol. 152 No. 3536 (2022)

Response to the first awake prone positioning relates with intubation rate in SARS-CoV-2 patients suffering from acute respiratory failure with moderate to severe hypoxaemia: a retrospective study

  • Ermes Lupieri
  • Andrea Boffi
  • Zied Ltaief
  • Antoine Schneider
  • Samia Abed-Maillard
  • Jean-Daniel Chiche
  • Mauro Oddo
  • Lise Piquilloud
Cite this as:
Swiss Med Wkly. 2022;152:w30212


AIMS OF THE STUDY: Awake prone positioning (aPP) in non-intubated patients with severe SARS-CoV-2-related pneumonia improves oxygenation and reduces the intubation rate, but no early predictors for success or failure of the strategy have been described. The main objective of this study was to assess whether response to the first aPP in terms of PaO2/FiO2, alveolar-arterial gradient (Aa-O2), respiratory rate and PaCO2 could predict the need for intubation. As secondary objective, we assessed the effects of aPP on the same parameters for all the sessions considered together.

METHODS: Retrospective analysis of consecutive SARS-CoV-2 pneumonia patients suffering from acute respiratory failure with moderate to severe hypoxaemia for whom aPP was performed for at least 45 minutes based on the prescription of the clinician in charge according to predefined criteria. Respiratory rate, blood gases and oxygenation parameters (PaO2/FiO2 and Aa-O2), before and after the first aPP were compared between patients who were subsequently intubated or not. Effects of all the aPP sessions together were also analysed.

RESULTS: One hundred and sixty-six patients were admitted for SARS-CoV-2 pneumonia during the study period. Among them, 50 received aPP lasting at least 45 minutes. Because 17 denied consent for data analysis and 2 were excluded because of a “do not intubate order”, 31 patients (for a total of 116 aPP sessions without any severe adverse events reported) were included. Among them, 10 (32.3%) were intubated. Mean age ± standard deviation (SD) was 60 ± 12 years. At ICU admission, respiratory rate was 26 ± 7/minute, median PaO2/FiO2 94 (interquartile range [IQR] 74–116) mm Hg and median Aa-O2 412 (IQR 286–427) mm Hg (markedly increased). Baseline characteristics did not statistically differ between patients who subsequently needed intubation or not. During the first aPP, PaO2/FiO2 increased and Aa-O2 decreased. When comparing patients who later where intubated or not, we observed, in the non intubated group only, a clinically significant decrease in median Aa-O2, from 294 (280–414) to 204 (107–281) mm Hg, corresponding to a 40% (26–56%) reduction, and a PaO2/FiO2 increase, from 103 (84–116) to 162 (138–195), corresponding to an increase of 48% (11–93%). The p value is <0.005 for both. When all the aPP sessions (n = 80) were considered together, aPP was associated with a significant increase in PaO2/FiO2 from 112 (80–132) to 156 (86–183) mm Hg (p <0.001) and Aa-O2 decrease from 304 (244–418) to 224 (148–361) mm Hg (p = 0.001).

CONCLUSIONS: Awake pronation in spontaneously breathing patients is feasible, and improves PaO2/FiO2 and Aa-O2. Response to the first session seems to be associated with lower intubation rate.


  1. Mauri T, Spinelli E, Scotti E, Colussi G, Basile MC, Crotti S, et al. Potential for Lung Recruitment and Ventilation-Perfusion Mismatch in Patients With the Acute Respiratory Distress Syndrome From Coronavirus Disease 2019. Crit Care Med. 2020 Aug;48(8):1129–34.
  2. Gattinoni L, Chiumello D, Caironi P, Busana M, Romitti F, Brazzi L, et al. COVID-19 pneumonia: different respiratory treatments for different phenotypes? Intensive Care Med. 2020 Jun;46(6):1099–102.
  3. Guérin C, Reignier J, Richard JC, Beuret P, Gacouin A, Boulain T, et al.; PROSEVA Study Group. Prone positioning in severe acute respiratory distress syndrome. N Engl J Med. 2013 Jun;368(23):2159–68.
  4. Nasa P, Azoulay E, Khanna AK, Jain R, Gupta S, Javeri Y, et al. Expert consensus statements for the management of COVID-19-related acute respiratory failure using a Delphi method. Crit Care. 2021 Mar;25(1):106.
  5. 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 [published online ahead of print, 2021 Aug 20]. Lancet Respir Med. 2021;S2213-2600(21)00356-8.
  6. Coppo A, Bellani G, Winterton D, Di Pierro M, Soria A, Faverio P, et al. Feasibility and physiological effects of prone positioning in non-intubated patients with acute respiratory failure due to COVID-19 (PRON-COVID): a prospective cohort study. Lancet Respir Med. 2020 Aug;8(8):765–74.
  7. Ferrando C, Mellado-Artigas R, Gea A, Arruti E, Aldecoa C, Adalia R, et al.; COVID-19 Spanish ICU Network. Awake prone positioning does not reduce the risk of intubation in COVID-19 treated with high-flow nasal oxygen therapy: a multicenter, adjusted cohort study. Crit Care. 2020 Oct;24(1):597.
  8. Vincent JL. Le manuel de réanimation, soins intensifs et médecine d'urgence. France. 5ème edition. Paris. France. Springer, 2017, chapter 2
  9. Piraino, Thomas et al. “Management of Adult Patients With Oxygen in the Acute Care Setting.”
  10. Respiratory care, respcare.09294. 2 Nov. 2022, doi:
  11. Thompson AE, Ranard BL, Wei Y, Jelic S. Prone Positioning in Awake, Nonintubated Patients With COVID-19 Hypoxemic Respiratory Failure. JAMA Intern Med. 2020 Nov;180(11):1537–9.
  12. Mellemgaard K. The alveolar-arterial oxygen difference: its size and components in normal man. Acta Physiol Scand. 1966 May;67(1):10–20.
  13. Weatherald J, Solverson K, Zuege DJ, Loroff N, Fiest KM, Parhar KK. Awake prone positioning for COVID-19 hypoxemic respiratory failure: A rapid review. J Crit Care. 2021 Feb;61:63–70.

Most read articles by the same author(s)