Gut hypoperfusion - reperfusion injury is an unavoidable event at the end of laparoscopic surgery. It produces oxidative stress (reactive oxygen species). Malondialdehyde have been demonstrated to be a reliable biomarker for the evaluation of oxidative stress in vivo. Propofol (2, 6 - diisopropylphenol), a highly liposoluble anaesthetic, has a potent antioxidant activity against lipid peroxidation in both in vitron and in vivo studies. On the basis of this knowledge, the investigators hypothesized that propofol has preventive effect for gut hypoperfusion - reperfusion induced injury in robot-assisted laparoscopic radical prostatectomy.

Increased intrabdominal pressure is associated with pneumoperitoneum for laparoscopic procedures and is one of the main factors in impairment of splanchnic perfusion by compressing vessels. An hypoperfusion - reperfusion human model is observed during and soon after laparoscopic surgery. After deflation of the abdomen, intrabdominal pressure and splanchnic blood flow normalize, representing reperfusion.

Reactive oxygen species is produced in metabolic and physiologic processes, and harmful oxidative reactions may occur in organisms that remove them via enzymatic and nonenzymatic antioxidative mechanisms.

Propofol (2, 6 - diisopropylphenol), a highly liposoluble anaesthetic, has a potent antioxidant activity against lipid peroxidation in both in vitron and in vivo studies. Propofol also attenuates ischemia - reperfusion induced lipid peroxidation in humans. On the basis of this knowledge, we hypothesized that propofol has preventive effect for gut hypoperfusion - reperfusion induced injury in robot-assisted laparoscopic radical prostatectomy.

Inclusion Criteria:

• patients receiving robot-assisted laparoscopic radical prostatectomy in ASA II-III physical status

Exclusion Criteria:

• history of sepsis or shock, clinically relevant cardiopulmonary disease, persistent tobacco abuse, recent antioxidant or vasoconstrictor use