Prone Positioning for Acute Respiratory Distress Syndrome without COVID-19

Abstract

Introduction: Prone positioning improves oxygenation in acute respiratory distress syndrome but carries risks and resource burdens. This review evaluates mortality benefit in non-COVID acute respiratory distress syndrome.

Methods: A systematic review of randomized trials comparing prone positioning for at least 12 hours daily versus supine positioning in adults with acute respiratory distress syndrome (PaO₂/FiO₂ ≤200). Studies enrolling exclusively COVID-19 patients were excluded. Primary outcome was 28-day mortality. Secondary outcomes included ventilator-free days and pressure ulcer incidence.

Results: Seven trials (2,159 patients) were included. Prone positioning reduced 28-day mortality from 40% to 32% (relative risk 0.80). The benefit was confined to patients with severe acute respiratory distress syndrome (PaO₂/FiO₂ ≤100). Ventilator-free days increased by 3.1 days. Facial pressure ulcers occurred in 22% of prone patients compared to 4% of supine patients.

Discussion: Prone positioning improves ventilation-perfusion matching by recruiting dorsal lung regions and reducing ventilator-induced lung injury. Mortality benefit was not apparent in earlier trials that used shorter prone durations (<8 hours per day) or did not target severe hypoxemia. Implementation requires trained staff and specialized beds.

Conclusions: Prone positioning reduces mortality in severe acute respiratory distress syndrome when applied for at least 12 hours daily. Patient selection based on hypoxemia severity is critical for benefit.