At the point of 15 minutes after turning to the lateral position and 15 minutes after two lung ventilation , Ppeak and Cdyn of two groups were significantly different ( P < 0.05 ) ( Ppeak :16 3 cmH ( 2 ) O , 16 3 cmH ( 2 ) O for VCV group and 14 2 cmH ( 2 ) O , 14 2 cmH ( 2 ) O for PCV-VG group ; Cdyn : 43.5 5.9 ml/cmH ( 2 ) O , 43.8 6.7 ml/cmH2O for VCV group and 49.7 7.1 ml/cmH ( 2 ) O , 53.3 9.6 ml/cmH ( 2 ) O for PCV-VG group ) .