Patients of group B received 6 ml/kg/h Plasmalyte A. Hemodynamic parameters MAP , HR and CVP were collected at 6 set points during the surgery : T1 : before AHH ; T2 : before anesthesia induction ; T3 : right intubation ; T4 : 10 min after intubation ; T5 : 20 min after intubation ; T6 : skin incision .