Diminishing Efficacy of Prone Positioning With Late Application in Evolving Lung Injury.

Objectives: It is not known how lung injury progression during mechanical ventilation modifies pulmonary responses to prone positioning. We compared the effects of prone positioning on regional lung aeration in late versus early stages of lung injury.

Design: Prospective, longitudinal imaging study.

Positional Therapy and Regional Pulmonary Ventilation.

Background: Prone ventilation redistributes lung inflation along the gravitational axis; however, localized, nongravitational effects of body position are less well characterized. The authors hypothesize that positional inflation improvements follow both gravitational and nongravitational distributions. This study is a nonoverlapping reanalysis of previously published large animal data.