Figure 2.
Single alveolar edema model. Optical sections (2 μm thick) of two alveoli at a depth of 20 μm below the pleural surface. Alveolar epithelium is labeled with calcein red–orange at transpulmonary pressures (Palv) of 5 (A, C), and 15 (B, D) cm H2O. Alveoli are air-filled (Control) or liquid-filled with albumin solution (Edema), as indicated. White arrows indicate septum separating the two alveoli. Yellow scale marks indicate alveolar diameters at Palv of 5 cm H2O in control condition. Aedem, cross-sectional area of right alveolus that becomes liquid-filled. Aadj, cross-sectional area of adjacent left alveolus that remains air-filled.