1 Department of Anesthesia and ICM, Clinique Saint-Luc de Bouge, Namur, Belgium, Department of Ambulatory Surgery, Clinique Saint-Luc de Bouge, Namur, Belgium, Department of Anesthesia and ICM, University of Liege, Liege, Belgium, [email protected] Department of Anesthesia and ICM, University of Liege, Liege, Belgium.