Linking Physiological Biomarkers of Ventilator-Induced Lung Injury to a Rich-Get-Richer Mechanism of Injury Progression.

Mechanical ventilation is a crucial tool in the management of acute respiratory distress syndrome, yet it may itself also further damage the lung in a phenomenon known as ventilator-induced lung injury (VILI). We have previously shown in mice that volutrauma and atelectrauma act synergistically to cause VILI. We have also postulated that this synergy arises because of a rich-get-richer mechanism in which repetitive lung recruitment generates initial small holes in the blood-gas barrier which are then expanded by over-distension in a manner that favors large holes over small ones. In order to understand the causal link between this process and the derangements in lung mechanics associated with VILI, we developed a mathematical model that incorporates both atelectrauma and volutrauma to predict how the propensity of the lung to derecruit depends on the accumulation of plasma-derived fluid and proteins in the airspaces. We found that the model accurately predicts derecruitment in mice with experimentally induced VILI.