Duration of anesthesia, defined as the time between induction of general anesthesia and awakening; Duration of surgery, defined as the time between surgical incision and the last stitch; Fentanyl consumption, expressed in mcg/kg /hour; Morphine consumption in the first 24 and 48 hours after the end of surgery; Pain (NRS) at rest and after deep inhalation 10 minutes after waking up, 24 and 48 hours after the end of surgery; Number of episodes of nausea and vomiting in the first 24 and 48 hours after the end of surgery; Consumption of antiemetic drugs in the first 24 and 48 hours after the end of surgery.