[Fractal dimension--a new EEG-based method of assessing the depth of anaesthesia].

Background: It has been suggested that analysis of the EEG signal using the fractal dimension method may be useful for assessment of depth of anaesthesia.

Methods: Thirty ASA I and II patients, scheduled for elective surgery under general anaesthesia were induced with midazolam, fentanyl and propofol and paralyzed with rocuronium or cis-atracurium. Clinical signs of the depth of anaesthesia were classified to one of five OAA/S levels.