Enhanced recovery after surgery (ERAS) protocols are multimodal perioperative care pathways designed to achieve early recovery and reducing postoperative morbidity after surgical procedures by maintaining preoperative organ function and reducing the profound stress response following surgery .The key elements of ERAS protocols include preoperative counselling, optimization of nutrition, standardized analgesic and anesthetic regimens , goal directed fluid therapy early mobilization.

For the proposed study investigators plan to include total 60 patients with 30 each allotted to GDFT(SVV) and CVP Group ,belonging to ASA ( American Society of Anesthesiology)Grade I/II/III, study will be conducted after obtaining written informed consent from all patients and approval from the scientific committee and Institutional Review Board (IRB). All patients will receive one-third starvation fluid as crystalloid during first hour of surgery . Night prior to and on the day of surgery carbo load will be given to all patients according to the protocol.Monitoring included 5 lead ECG SPO2,ETCO2, Invasive Blood Pressure (IBP - Radial),CVP(site IJV),core Temperature .

Standard General anaesthesia with oral Endotracheal tube and Intermittent Positive Pressure Ventilation will be given to all patients.Patients will be allotted randomly to either Goal Directed Fluid Therapy (GDFT) /SVV - Stroke Volume Variation or Conventional Central Venous Pressure - CVP guided fluid Therapy Group.

During the surgery - Heart rate , Mean arterial Blood Pressure , Urine output , Blood loss , Seum lactate levels will be noted.

For SVV Group - SVV , Stroke Volume Index (SVI) , Systemic vascular resistance index (SVRI) ,Cardiac Index (CI) values will be noted every 30 minutes- the goal is to maintain SVV value >11 and to give colloid bolus 200ml whenever SVV values rise above11.Pre and post bolus SVV, SV, SVI and SVRI shall be recorded.

For CVP Group - Goal is to maintain CVP values between 8-12 cmsH20 and for decrease in value < 8 colloid bolus of 200ml will be given and change in CVP value will be noted.

Patients in both the groups will receive Noradrenaline infusion if MAP <70 mmHg with optimal fluid transfusion .Target for transfusing Packed red blood cells will be value of haematocrit < 24 Postoperative HR, MAP, I/O-charting, Serum Creatinine, Serum Lactate, bowel sounds, Inotrope requirement, Visual Analogue Score, Ryles Tube Feeds, Epidural analgesia ,Length of stay (hours in SICU) and any postoperative complications shall be noted.

Inclusion Criteria:

• Elective major open gastrointestinal Oncosurgeries .

Exclusion Criteria:

• Patient refusal.
• Robotic surgery.
• Laparoscopic surgery.
• Arrythmias.

Participant will be masked about allotment of interventional group either CVP or SVV .