Pcv Vg Versus Vcv Ventilation Mode Effects On Hemodynamics

The primary outcome is to compare the hemodynamic outcomes ( e.g SV , CO and CI ) using The ICON of two different modes of ventilation ( VCV and PC-VG ) during laparoscopic abdominal cancer surgeries with exaggerated trendelenburg position. And the secondary outcomes is to compare the respiratory effects ( e.g atelectasis development , plateau pressure(Pplat) , peak inspiratory pressure(PIP) , dyn. compliance and postoperative inflammatory indicators e.g CRP and WBCs ) of two different modes of ventilation ( VCV and PC-VG ) during laparoscopic abdominal cancer surgeries with exaggerated trendelenburg position.