Background
Summary of Chad T, Sampson C. Prone positioning in conscious patients on medical wards: A review of the evidence and its relevance to patients with COVID-19 infection. Clin Med 2020;20:e97–103.
Prone positioning (PP) in non-COVID-19 acute respiratory distress syndrome (ARDS) has an established evidence base, particularly in intubated and mechanically ventilated (IMV) patients.1 First proposed in the 1970s, clinical trials have shown that the majority of prone patients (>70%) with moderate to severe ARDS have considerable improvements in oxygenation, with average increases in PaO2/FiO2 ranging from 34–62%, and a significant reduction in both mortality and ventilator-associated pneumonia (VAP).2–6
Recruitment of dorsal (dependent) alveoli (thus improving ventilation/perfusion (V/Q) matching), a more homogenous pulmonary perfusion pattern and drainage of secretions are the physiological mechanisms by which PP works.3,7,8
The majority of data concerning PP centres around IMV patients in the intensive care unit (ICU) setting. Following a recent worldwide surge in the demand for high-dependency monitoring and ICU admission, can this evidence be extrapolated to conscious, non-ventilated, ward-based patients with COVID-19?
Review of the literature
Several reports have emerged concerning PP in conscious patients who fail to respond to non-invasive oxygenation, either via high-flow nasal cannula (HFNC) circuits or continuous positive airway pressure (CPAP) ventilation.9–11 With limitations in study design and differences in both inclusion criteria and outcome data, it is difficult to categorically determine whether PP was an effective intervention. This is further compounded by lack of pre-pandemic study into PP on ward-based settings.
In short, the existing evidence base is too small for conclusions to be made regarding the efficacy of PP in conscious patients. While preliminary findings, in regards to improved oxygenation (25–100% of patients) coupled with intelligible underlying physiological mechanisms are encouraging, for PP to be definitively considered a useful intervention in the management of COVID-19 on ward-based patients, further evaluation is needed.12
What does this mean in practice?
PP is an achievable and relatively safe intervention that has been shown to improve oxygenation in a proportion of conscious ward-based patients.
PP can be trialled on suitable patients on the wards if respiratory deterioration is observed. It is not a substitute for IMV but may defer the need for IMV (further study is needed).
‘Prone teams’ can facilitate in the identification and proning of suitable patients. This is particularly important in the significant cohort of obese patients observed with COVID-19.
References
- 1.Gattinoni L, Busana M, Giosa L, Macrì M, Quintel M. Prone positioning in acute respiratory distress syndrome. Semin Resp Crit Care 2019;40:94–100. [DOI] [PubMed] [Google Scholar]
- 2.Piehl MA, Brown RS. Use of extreme position changes in acute respiratory failure. Crit Care Med 1976;4:13–4. [DOI] [PubMed] [Google Scholar]
- 3.Kallet RH. A comprehensive review of prone position in ARDS. Respir Care 2015;60:1660–87. [DOI] [PubMed] [Google Scholar]
- 4.Guérin C, Reignier J, Richard JC, et al. Prone positioning in severe acute respiratory distress syndrome. N Engl J Med 2013;368:2159–68. [DOI] [PubMed] [Google Scholar]
- 5.Li Bassi G, Torres A. Ventilator-associated pneumonia: role of positioning. Curr Opin Crit Care 2011;17:57–63. [DOI] [PubMed] [Google Scholar]
- 6.Galiatsou E, Kostanti E, Svarna E, et al. Prone position augments recruitment and prevents alveolar overinflation in acute lung injury. Am J Respir Crit Care Med 2006;174:187–97. [DOI] [PubMed] [Google Scholar]
- 7.Pelosi P, Tubiolo D, Mascheroni D, et al. Effects of the prone position on respiratory mechanics and gas exchange during acute lung injury. Am J Respir Crit Care Med 1998;157:387–93. [DOI] [PubMed] [Google Scholar]
- 8.Koulouras V, Papathanakos G, Papathanasiou A, Nakos G. Efficacy of prone position in acute respiratory distress syndrome patients: A pathophysiology-based review. World J Crit Care Med 2016;5:121–36. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Caputo N, Strayer R, Levitan R. Early self-proning in awake, non- intubated patients in the emergency department: a single ED's experience during the COVID-19 pandemic. Acad Emerg Med 2020;27:375–8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Elharrar X, Trigui Y, Dols A, et al. Use of prone positioning in nonintubated patients with COVID-19 and hypoxemic acute respiratory failure. JAMA 2020;323:2336–8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Sartini C, Tresoldi M, Scarpellini P, et al. Respiratory parameters in patients with COVID-19 after using noninvasive ventilation in the prone position outside the intensive care unit. JAMA 2020;323:2338–40. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.NHS England Clinical guide for the management of critical care patients during the coronavirus pandemic. NHS, 2020. www.england.nhs.uk/coronavirus/wp-content/uploads/sites/52/2020/03/specialty-guide-itu-and-coronavirus-v1-16-march-2020.pdf [Accessed 24 June 2020].