Fig. 4

Regional distribution of pulmonary ventilation in the control (left, n = 4) and injured (right, n = 6) groups. Larger PEEP levels were associated with greater percent increase in the ventilation of the dependent lung in the injured group than in the control group. Similarly, larger V_T was associated with a greater percent increase in dependent lung ventilation in the injured group than in the control group. * indicates greater percent increase in the ventilation of the dependent lung region with larger PEEP in the injured than in the control group; † indicates greater percent increase in the ventilation of the dependent lung region with larger V_T in the injured than in the control group. PEEP = positive end-expiratory pressure. V_T = tidal volume