Bench-to-bedside review: Biotrauma and modulation of the innate immune response.

The innate immune network is responsible for coordinating the initial defense against potentially noxious stimuli. This complex system includes anatomical, physical and chemical barriers, effector cells and circulating molecules that direct component and system interactions. Besides the direct effects of breaching pulmonary protective barriers, cyclic stretch generated during mechanical ventilation (MV) has been implicated in the modulation of the innate immunity. Evidence from recent human trials suggests that controlling MV-forces may significantly impact outcome in acute respiratory distress syndrome. In this paper, we explore the pertinent evidence implicating biotrauma caused by cyclic MV and its effect on innate immune responses.