[EEG-Monitoring to avoid awareness during anaesthesia - benefit or luxury?].

The intraoperative perception of pain, anxiety and helplessness is a serious complication of anaesthesia, the frequency is now 0,1-0,2 %. Post-operative memories can cause posttraumatic stress disorder (PTSD), but this will require a consolidation of conscious awareness in the long-term memory. Memory formation is promoted by high emotional contents and a longer duration of awareness. There are defined risk factors for awareness, including patient factors, surgery and anaesthesia technique. In patients with high risk of awareness EEG monitoring can decrease the incidence. Because of lack of evidence, its use in every anaesthesia cases is an option but not a must.