All patients will be premedicated the night before surgery with bromazepam 3 mg PO, and 0.1 mg/Kg morphine sulphate IM one hour preoperatively. Upon arrival to the pre-induction room, the patient will receive supplementary oxygen via a nasal cannula, and will be monitored with ECG, Non invasive blood pressure and pulse oximeter. Under local infiltration anesthesia (lidocaine 2%) a peripheral venous cannula (14 or 16 G) and a 20 G arterial cannula will be inserted. Induction of anesthesia will be accomplished with fentanyl (7-10 μg/Kg), propofol 0.5 - 1.0 mg/Kg and pancuronium (0.08 - 0.12 mg/Kg). After intubation a triple lumen central venous catheter will be inserted in a central vein. The temperature probe will be inserted in the nasopharynx; the TEE probe will be also inserted after decompression of the stomach with a nasogastric tube.