Fig. 3. Regional lung function before (filled bars ) and after (open bars ) the recruitment maneuver (RM) in nondependent (ND), middle (M), and dependent (D) regions. (A ) Mean-normalized gas fraction (F^G) decreased from the ND to the D region. (B)  The fraction of imaged pulmonary blood flow that was shunted in each region (F^QS) increased from the ND to the D region. The RM further increased F^QSin the D region. (C ) The fraction of imaged pulmonary flood flow going to each region (F^G) increased from the ND to the D region. The RM decreased perfusion to the M region and shifted it to the D region. Data are mean ± SD *P < 0.05, **P < 0.01 between ND, M, and D regions before the RM, §P < 0.05 before versus  after the RM.