Comparison of Two Electroencephalograms (EEG) Monitors in Patients Undergoing General Anesthesia

Hypothesis: There is a statistically measurable correlation between qNOX and rough clinical signs of insufficient anti-nociception such as movements during Laryngeal Mask Airway (LMA) insertion, skin Incision, LMA removal. It will reduce the problem of anticipating the nociception in patients undergoing general anesthesia. Objectives: 1. to compare two indexes of hypnosis, the qCON (Quantium Medical, Spain) with the Bispectral index (BIS™) (Covidien, Boulder CO. USA), in patients undergoing surgery under sedation and general anesthesia. 2. to assess the qNOX index of pain/nociception (Quantium Medical, Barcelona, Spain) and the qCON index of hypnosis. 3. to assess qNOX reliability as a specific indicator of response to nociceptive stimulation.