The study proposes to analyze the difference in the rapidity of the recovery of post operative cognition immediately after extubation and 20, 40 and 60 minutes post extubation and neuropsychological complications (delirium) after 48 hours following general anesthesia using a prospective, randomized approach. Patients undergoing any type of surgery with the exception of cranial, cardiac or thoracic surgery can be enrolled in the study.