Abstract
Background: Acute respiratory distress syndrome (ARDS) is a condition characterized by an acute, diffuse, inflammatory lung injury with high morbidity and mortality. Since it was first reported in 1976, prone position has been increasingly used to treat patients with ARDS as it improves oxygenation. However, the evidence on mortality is conflicting. Objective: The purpose of this project thesis is to assess the effect on mortality of prone positioning in patients with moderate and severe ARDS. Material and methods: A literary review was conducted January 2021 through a search in PubMed database. Only randomized controlled studies were included. To be included, studies had to meet the selected PICO-criteria: P; adults with moderate or severe ARDS, I; prone position, C: supine position or conventional treatment, O; mortality/survival. The search included several MeSH-terms and was limited to English articles. Results: Based on the PICO-criteria, five articles were included, addressing mortality as their primary endpoint. All of the five articles found an improvement in mortality in patients turned prone in contrast to supine. However, only one of the studies managed to achieve a statistically significant improvement. The remaining four articles failed to show a significant reduction in mortality in patients randomized to the prone position and were prematurely stopped mostly due to a low patient recruitment rate. Conclusion: Prone position may have a beneficial effect on mortality, even though underpowered RCT studies have failed to confirm a direct positive effect on mortality in adult patients with ARDS. Factors such as duration and application of prone positioning, as well as the interval between onset of ARDS should be taken in consideration when considering the effect of prone position.