Figure 2

Lung injury. Wet to dry lung weight (W/D) ratios and lung injury scores in rats ventilated for 4 h after acid instillation or during sepsis with low tidal volume (LVt) (6 mL/kg), with a positive end-expiratory pressure (PEEP) of 5 cm H₂O or high tidal volume (HVt) (15 mL/kg), without PEEP. Acid instillation increased W/D ratio as compared to sepsis. The effect of mechanical ventilation (MV) with HVt on W/D ratio was greater after acid instillation than during sepsis (A). Acid instillation increased lung injury score as compared to sepsis. The effect of HVt MV on lung injury score was greater after acid instillation than during sepsis. Panels (C) to (H) are representative micrographs demonstrating lung injury for: (C) Control rats, (D) and (E) demonstrate increased lung injury observed after acid instillation and MV with (D) LVt and (E) HVt. Sepsis alone increased lung injury (F); MV did not have an effect with either (G) LVt, or (H) HVt. Original magnification × 100. * p < 0.001 for model compared to LVt and HVt sepsis. # p < 0.001 for interaction between model and MV, % p = 0.04 for interaction between model and MV.