 The main objective of this study is to evaluate the incidence of akathisia with Droperidol, the prophylactic treatment of post operative nausea and vomiting, used at two different doses, versus control group Ondansetron, in outpatient surgery.The primary endpoint is to compare the number of observed akathisia Barnes score 1 in the Droperidol arms 0,625 mg and 1,25 mg versus Ondansetron 4 hours after recovery from anesthesia.The assumption is that there is a greater risk of akathisia among patients taking Droperidol in prevention of NPVO, that among patients taking Ondansetron. 