Fig. 2.

A representative photomicrographs (light microscopy) of lung parenchyma stained with hematoxylin–eosin. Photomicrographs are representative of data obtained from lung sections of 7 animals (original magnification, × 400). Bars = 100 μm. Note the presence of interstitial edema (asterisk), lung overdistension (double arrows), and alveolar-capillary damage (presence of neutrophils and erythrocytes in the alveolar septa) (two arrows). B diffuse alveolar damage (DAD) score; scores arithmetically averaged from two independent investigators representing injury from interstitial edema, overdistension, alveolar collapse, septal inflammation, and alveolar hemorrhage. Boxes show the interquartile (25–75%) range, whiskers encompass the range (minimum to maximum), and horizontal lines represent median values of seven animals/group. Rats received a standard (10 mL/kg/h, NORMO) or high (30 mL/kg/h, HIGH) volume of Ringer’s lactate. FAST: abrupt PEEP decrease from 9 to 3 cmH₂O; SLOW: gradual PEEP decrease (0.2 cmH₂O/min) from 9 to 3 cmH₂O