Prone positioning in ARDS

Intensive Care Medicine: Published: 20 July 2026

Abstract

Over the past five decades, prone positioning has evolved from single case reports to an evidence-based intervention. Initially used as a rescue therapy, it is now recognized as an integral component of lung-protective mechanical ventilation strategies, applied early in intubated patients with acute respiratory distress syndrome (ARDS) with a PaO₂/F_IO₂ ratio < 150 mmHg. The COVID-19 pandemic further expanded its use to non-intubated patients, the so-called awake prone position (APP), with promising results. APP requires confirmation in non-COVID patients and in a more routine ICU practice. Improved oxygenation is a consistent and well-recognized effect of prone positioning in both intubated and non-intubated patients with ARDS. Beyond its effects on gas exchange, prone positioning mitigates ventilator-induced lung injury by reducing lung stress and strain and may also confer favorable hemodynamic effects. This article reviews the physiologic rationale for prone positioning, evidence from randomized controlled trials, current guideline recommendations, practical aspects of implementation, and ongoing questions in both intubated and non-intubated patients.

 

Effects of prone positioning on lung mechanical power components in patients with acute respiratory distress syndrome: a physiologic study

 

by Christoph Boesing, Joerg Krebs, Alice Marguerite Conrad, Matthias Otto, Grietje Beck, Manfred Thiel, Patricia R. M. Rocco, Thomas Luecke and Laura Schaefer 

 

Critical Care volume 28, Article number: 82 (2024) Published: 15 March 2024

 

Background

Prone positioning (PP) homogenizes ventilation distribution and may limit ventilator-induced lung injury (VILI) in patients with moderate to severe acute respiratory distress syndrome (ARDS). The static and dynamic components of ventilation that may cause VILI have been aggregated in mechanical power, considered a unifying driver of VILI. PP may affect mechanical power components differently due to changes in respiratory mechanics; however, the effects of PP on lung mechanical power components are unclear. This study aimed to compare the following parameters during supine positioning (SP) and PP: lung total elastic power and its components (elastic static power and elastic dynamic power) and these variables normalized to end-expiratory lung volume (EELV).

Methods

This prospective physiologic study included 55 patients with moderate to severe ARDS. Lung total elastic power and its static and dynamic components were compared during SP and PP using an esophageal pressure-guided ventilation strategy. In SP, the esophageal pressure-guided ventilation strategy was further compared with an oxygenation-guided ventilation strategy defined as baseline SP. The primary endpoint was the effect of PP on lung total elastic power non-normalized and normalized to EELV. Secondary endpoints were the effects of PP and ventilation strategies on lung elastic static and dynamic power components non-normalized and normalized to EELV, respiratory mechanics, gas exchange, and hemodynamic parameters.

Results

Lung total elastic power (median [interquartile range]) was lower during PP compared with SP (6.7 [4.9–10.6] versus 11.0 [6.6–14.8] J/min; P < 0.001) non-normalized and normalized to EELV (3.2 [2.1–5.0] versus 5.3 [3.3–7.5] J/min/L; P < 0.001). Comparing PP with SP, transpulmonary pressures and EELV did not significantly differ despite lower positive end-expiratory pressure and plateau airway pressure, thereby reducing non-normalized and normalized lung elastic static power in PP. PP improved gas exchange, cardiac output, and increased oxygen delivery compared with SP.

Conclusions

In patients with moderate to severe ARDS, PP reduced lung total elastic and elastic static power compared with SP regardless of EELV normalization because comparable transpulmonary pressures and EELV were achieved at lower airway pressures. This resulted in improved gas exchange, hemodynamics, and oxygen delivery.

 

Extended prone positioning for intubated ARDS: a review

 

by Thaïs Walter and Jean-Damien Ricard 

 

Critical Care volume 27, Article number: 264 Published: 05 July 2023

 

During the COVID-19 pandemic, several centers had independently reported extending prone positioning beyond 24 h. Most of these centers reported maintaining patients in prone position until significant clinical improvement was achieved. One center reported extending prone positioning for organizational reasons relying on a predetermined fixed duration. A recent study argued that a clinically driven extension of prone positioning beyond 24 h could be associated with reduced mortality. On a patient level, the main benefit of extending prone positioning beyond 24 h is to maintain a more homogenous distribution of the gas–tissue ratio, thus delaying the increase in overdistention observed when patients are returned to the supine position. On an organizational level, extending prone positioning reduces the workload for both doctors and nurses, which might significantly enhance the quality of care in an epidemic. It might also reduce the incidence of accidental catheter and tracheal tube removal, thereby convincing intensive care units with low incidence of ARDS to prone patients more systematically. The main risk associated with extended prone positioning is an increased incidence of pressure injuries. Up until now, retrospective studies are reassuring, but prospective evaluation is needed.