During the study, at predefined times, we will assess different levels of sedation (OAA/S score) and the reaction on tetanic stimulation of the ulnar nerve, insertion of a laryngeal mask airway and laryngoscopy. In addition heart rate, SpO2 and capnography will be recorded continuously and non invasive bloodpressure will be recorded using a 1 minute interval time. Spectral entropy and BIS derived from the frontal EEG will be used to monitor clinical cerebral drug effect.