Fig. 2.

Heterogeneous alveolar injury depicted as a cluster of collapsed alveoli in the center of the field (H) surrounded by open interdependent alveoli (hexagons). Note the distortion and overdistension of the patent alveoli adjacent to the collapsed alveolar cluster (asterisks), with more overdistension alveoli at expiration (B) compared with inspiration (A). The larger the change in size of these alveoli with each breath, the larger the dynamic strain-induced tissue damage. These dynamic changes can be seen in Supplemental Animation S2.