EEG and Depth of Anaesthesia Monitoring

This chapter summarises the relationship between the electroencephalogram (EEG) and sleep including the changes produced in the EEG by medications used to induce and maintain general anaesthesia. These changes are used by the depth of anaesthesia monitors to inform clinicians about a patients’ level of consciousness and to help avoid anaesthetic awareness. The various depths of anaesthesia monitors are summarised as are some of the principles used to derive the value they display.