Prone Positioning of Nonintubated Patients with Coronavirus Disease 2019 - A Systematic Review and Meta-Analysis

OBJECTIVES: Several studies have reported prone positioning of nonintubated patients with coronavirus diseases 2019-related hypoxemic respiratory failure. This systematic review and meta-analysis evaluated the impact of prone positioning on oxygenation and clinical outcomes. DESIGN AND SETTING: We searched PubMed, Embase, and the coronavirus diseases 2019 living systematic review from December 1, 2019, to November 9, 2020. SUBJECTS AND INTERVENTION: Studies reporting prone positioning in hypoxemic, nonintubated adult patients with coronavirus diseases 2019 were included. MEASUREMENTS AND MAIN RESULTS: Data on prone positioning location (ICU vs non-ICU), prone positioning dose (total minutes/d), frequency (sessions/d), respiratory supports during prone positioning, relative changes in oxygenation variables (peripheral oxygen saturation, Pao2, and ratio of Pao2 to the Fio2), respiratory rate pre and post prone positioning, intubation rate, and mortality were extracted. Twenty-five observational studies reporting prone positioning in 758 patients were included. There was substantial heterogeneity in prone positioning location, dose and frequency, and respiratory supports provided. Significant improvements were seen in ratio of Pao₂to the Fio₂(mean difference, 39; 95% CI, 25-54), Pao₂(mean difference, 20 mm Hg; 95% CI, 14-25), and peripheral oxygen saturation (mean difference, 4.74%; 95% CI, 3-6%). Respiratory rate decreased post prone positioning (mean difference, -3.2 breaths/min; 95% CI, -4.6 to -1.9). Intubation and mortality rates were 24% (95% CI, 17-32%) and 13% (95% CI, 6-19%), respectively. There was no difference in intubation rate in those receiving prone positioning within and outside ICU (32% [69/214] vs 33% [107/320]; p = 0.84). No major adverse events were recorded in small subset of studies that reported them. CONCLUSIONS: Despite the significant variability in frequency and duration of prone positioning and respiratory supports applied, prone positioning was associated with improvement in oxygenation variables without any reported serious adverse events. The results are limited by a lack of controls and adjustments for confounders. Whether this improvement in oxygenation results in meaningful patient-centered outcomes such as reduced intubation or mortality rates requires testing in well-designed randomized clinical trials.