Figure 2.
The baby lung concept and regional overexpansion. White circles represent functional aerated or recruitable units. Black circles represent non-recruitable units. In the healthy lung (top), distribution of tidal volume across lung units results in normal, non-injurious ventilation whereas in the heterogeneously injured lung (bottom), nonuniform distribution of tidal volume occurs to preferentially recruitable units, causing overexpansion and potential injury to basement and plasma membranes.