Does Prone Positioning Improve Oxygenation in COVID-19–Related ARDS?

Extracorporeal Membrane Oxygenation Machine
Extracorporeal Membrane Oxygenation Machine
How does prone positioning affect pulmonary outcomes in patients with COVID-19–associated ARDS, including those using invasive and noninvasive ventilation?

Use of the prone position significantly improved oxygen saturation in patients with COVID-19–associated acute respiratory distress syndrome (ARDS) — both prone positioning used by individuals in the intensive care unit (ICU) requiring invasive mechanical ventilation and awake self-prone positioning (ASPP) used by patients on noninvasive ventilation. These were among the results of a comprehensive literature search and meta-analysis recently published in the journal Intensive and Critical Care Nursing

The literature search included all studies with prospective and experimental designs that evaluated the effect of prone positioning in patients with COVID-19–related ARDS. All analytic studies — both observational and experimental — that evaluated the prone position, either with or without a control group, were included. Prospective study approaches were included in the meta-analysis, as they ranked higher in the hierarchy of evidence than did studies with retrospective designs.

The primary study outcome was the ratio of arterial oxygen partial pressure/fractional inspired oxygen (PaO2/FiO2) after an individual was in the prone position. Secondary study outcomes included other respiratory physiology parameters, such as oxygen saturation (SpO2) and PaO2.

The data obtained included study characteristics (ie, design, country, and setting); characteristics of the participants (ie, sample, gender, mean age, and mean BMI); characteristics of the intervention (ie, frequency, duration, and total time in prone position, time measurement, and respiratory support intervention); and study outcome (ie, PaO2/FiO2, SpO2, and PaO2).

A total of 15 articles fulfilled eligibility criteria and were included in the final analysis. All of the studies included in the meta-analysis were published in 2020 and 2021, given that the first case of COVID-19 was identified at the end of 2019. The settings of the studies were in the ICU (8 studies) and outside of the ICU (7 studies). From these studies, a total of 288 participants were identified, with the range of the sample sizes in each study varying from 7 to 50 individuals. Overall, 65% of the participants were male. Patients’ age ranged from 38 to 87 years; BMI ranged from 24 to 36 kg/m2. The frequency of the interventions ranged from 1 to 3 times per day, with a duration of 0.5 to 12 hours per day.

Use of the prone position exhibited a statistically significant effect in improving PaO2/FiO2 (standardized mean difference [SMD], 1.10; 95% CI, 0.60-1.59), SpO2 (SMD, 3.39; 95% CI, 1.30-5.48), and PaO2 (SMD, 0.77; 95% CI, 0.19-1.35). Patients with higher BMIs and longer duration/day had larger SMD effect sizes for prone positioning.

Limitations of the current meta-analysis include the fact that it used data from single-arm observational case series studies, and that some cohort studies used had no comparator groups. Although heterogeneity was present, sensitivity analyses were performed to account for the heterogeneity.

The investigators concluded that “both traditional ICU prone positioning and ASPP are effective for patients with COVID-19 ARDS.” Study results also support implementation of the prone position in patients with higher BMIs. Longer durations of prone position are recommended for achieving greater benefits in the traditional ICU prone position.


Ashra F, Chen R, Kang XL, et al. Effectiveness of prone position in acute respiratory distress syndrome and moderating factors of obesity class and treatment durations for COVID-19 patients: a meta-analysis. Intensive Crit Care Nurs. Published online April 11, 2022. doi:10.1016/j.iccn.2022.103257