In group A induction of anesthesia will be performed with Propofol (2mg/kg), Cisatracurium (0.15mg/kg)and continous infusion of Remifentanil (0.15mcg/kg/min).Anesthesia will be maintained by Sevoflurane with oxygen (Fi=40%)and air, with a MAC value to maintain BIS between 40 and 60. Intraoperative analgesia will be obtained with Remifentanil 0.15-0.25mcg/kg/min. Additional boluses of Cisatracurium (0.02mcg/kg)will be administered as needed during surgery. At the beginning of closure of the peritoneum bolus of morphine (0.1mg/kg)and acetaminophen 1g will be administered. Propofol and remifentanil infusions will be interrupted at the end of wound closure.

In group B anesthesia will be induced by Propofol (2mg/kg), Fentanyl (2mcg/kg)and Cisatracurium (0.15mg/kg). Anesthesia will be maintained by Sevoflurane, oxygen (Fi=40%) and air and boluses of Fentanyl (50mcg). additional boluses of Cisatracurium (0.02mg/kg)will be administered as needed during surgery. At the beginning of closure of the peritoneum acetaminophen 1g will be administered.

In group A induction of anesthesia will be performed with Propofol (2mg/kg), Cisatracurium (0.15mg/kg)and continous infusion of Remifentanil (0.15mcg/kg/min).Anesthesia will be maintained by Sevoflurane with oxygen (Fi=40%)and air, with a MAC value to maintain BIS between 40 and 60. Intraoperative analgesia will be obtained with Remifentanil 0.15-0.25mcg/kg/min. Additional boluses of Cisatracurium (0.02mcg/kg)will be administered as needed during surgery. At the beginning of closure of the peritoneum bolus of morphine (0.1mg/kg)and acetaminophen 1g will be administered. Propofol and remifentanil infusions will be interrupted at the end of wound closure.

In test of Rey to the subject is presented for 5 times the same list of 15 bisyllabic words or trisillabic common use of which he must recall as many as possible within 1 minute; after about 15 minutes the patient, meanwhile distracted by the test , must again try to remember the greatest number possible without a further reading. The maximum possible score of the first phase of the test is an expression of the ability of short term memory of the subject, the result of the test is repeated at a distance of 15 minutes is indicative of its storage capacity, to intermediate term.

In the Stroop Test patient is instructed to read a random sequence of adjectives "green", "red", "blue" written in black font, then he refers the colour of a succession of circumferences filled of the three colors above in random order; finally, another random succession of three words "green", "red", "blue" written in three characters of the same colors, but not associated with corresponding adjective. Number of errors that the subject does in reading is an indication of its ability to attention

Blood samples will be made for the quantitative determination of serum cytokines IL-1β, IL-6, IL-8, TNF-α, IL-10 and IL-12. Determinations will be given by Multiplex Elisa method.