The Effect of Intraoperative Goal Directed Restricted Fluid Therapy on Extravascular Lung Water

Patients will receive restricted fluid management (2ml/Kg/h) with concomitant SVV monitoring using ICON cardiometry device. GDT protocol will be used to fulfil the two targets (SVV \< 10% - MAP \>65 mmHg). A fluid bolus of 200 ml Lactated ringer will be infused if SVV is more than 10% for 5 minutes, the dose will be repeated every 10 minutes if SVV is still above 10%. If the total fluid boluses reached 20 ml/Kg in a patient with MAP \> 65 mmHg, no fluid boluses will be infused unless there is evident blood loss or hypotension. If MAP was achieved (\>65mmHg) at any time, the first three steps in the protocol will be bypassed. If MAP was not achieved after reaching 20 ml/Kg , norepinephrine (inotropes) will be given as shown in fig. 1 with dose of 0.01ug/kg/min.

Patients will receive standard fluid management of 6 ml/Kg/h plus rescue fluid boluses of 200 ml lactated ringer if Mean arterial pressure (MAP) decreased less than 65 mmHg and central venous pressure less than 8 mmH2o.