Fig. 3. Gas fraction (A ), mean normalized perfusion (B ), and shunt fraction (C ) in the ventral, middle, and dorsal regions in the control (n = 6) and endotoxin (n = 6) groups of supine sheep at baseline and after 2 h of mechanical ventilation with positive end-expiratory pressure = 0 cm H2O and plateau pressure of 30-32 cm H2O. Data are expressed as box (median, twenty-fifth, and seventy-fifth percentile) and whiskers (range) for each region, group, and time point. On the x axis, “b” indicates measurements at baseline, and “2h” indicates measurements after 2 h of mechanical ventilation. *P < 0.05 versus baseline.