The efficacy and tolerance of prone positioning in non-intubation patients with acute hypoxemic respiratory failure and ARDS: a meta-analysis.

Background and Aims: The application of prone positioning with acute hypoxemic respiratory failure (AHRF) or acute respiratory distress syndrome (ARDS) in non-intubation patients is increasing gradually, applying prone positioning for more high-flow nasal oxygen therapy (HFNC) and non-invasive ventilation (NIV) patients. This meta-analysis evaluates the efficacy and tolerance of prone positioning combined with non-invasive respiratory support in patients with AHRF or ARDS.
Methods: We searched randomized controlled trials (RCTs) (prospective or retrospective cohort studies, RCTs and case series) published in PubMed , EMBASE and the Cochrane Central Register of Controlled Trials from 1 January 2000 to 1 July 2020. We included studies that compared prone and supine positioning with non-invasive respiratory support in awake patients with AHRF or ARDS. The meta-analyses used random effects models. The methodological quality of the RCTs was evaluated using the Newcastle-Ottawa quality assessment scale.
Results: A total of 16 studies fulfilled selection criteria and included 243 patients. The aggregated intubation rate and mortality rate were 33% [95% confidence interval (CI): 0.26-0.42, I ²  = 25%], 4% (95% CI: 0.01-0.07, I ²  = 0%), respectively, and the intolerance rate was 7% (95% CI: 0.01-0.12, I ²  = 5%). Prone positioning increased PaO ₂ /FiO ₂ [mean difference (MD) = 47.89, 95% CI: 28.12-67.66; p  < 0.00001, I ²  = 67%] and SpO ₂ (MD = 4.58, 95% CI: 1.35-7.80, p  = 0.005, I ²  = 97%), whereas it reduced respiratory rate (MD = -5.01, 95% CI: -8.49 to -1.52, p  = 0.005, I ²  = 85%). Subgroup analyses demonstrated that the intubation rate of shorter duration prone (⩽5 h/day) and longer duration prone (>5 h/day) were 34% and 21%, respectively; and the mortality rate of shorter duration prone (⩽5 h/day) and longer duration prone (>5 h/day) were 6% and 0%, respectively. PaO ₂ /FiO ₂ and SpO ₂ were significantly improved in COVID-19 patients and non-COVID-19 patients.
Conclusion: Prone positioning could improve the oxygenation and reduce respiratory rate in both COVID-19 patients and non-COVID-19 patients with non-intubated AHRF or ARDS. The reviews of this paper are available via the supplemental material section.