in our study the investigators aim to assess the effect of terlipressin on cerebral oxygenation monitored by cerebral oxymetry and cerebral blood flow measured by transcranial doppler.

All patients will receive 6ml /kg/h Ringer acetate solution as a maintenance intraoperative fluid. If pulse pressure variations (PPV) is more than 15%, the patient will be considered as fluid responder and will receive a 250-ml bolus of albumin 5% to maintain PPV ≤15%. Blood transfusion will be given based on a hemoglobin level (< 7 g/dl) in both (control group) and (terlipressin group). Other blood products will be transfused guided by lab result; Fresh frozen plasma will be given when INR > 2 and platelets will be given when platelets <30.000/mm3. The patients will be randomly allocated into 2 groups; Group T (Terlipressin group) and group S (Normal saline 0.9%).

For (terlipressin group) all patients will receive loading dose of terlipressin (1mg diluted with 50 ml of normal saline 0.9% solution over 30 min) and it will be maintained by continuous infusion at rate of 160 μg per hour (8 ml/h).

For (control group) all patient will receive 50 ml of normal saline 0.9% solution over 30 min and will be maintained continuous infusion at rate of 8 ml/h.

Drugs will be prepared by the nurse and the investigator will be blinded to the drug given.

Inclusion Criteria:

• ASA II-IV undergoing orthotopic liver transplantation.
• Age above 18 years.

Exclusion Criteria:

• Age below 18 years.
• Patients on Terlipressin preoperative.
• Patients known allergic to Terlipressin.
• Portal vein thrombosis.
• Ischemic heart disease.
• Patients with T. bilirubin level above 7 mg/dl