A 60 year old female patient underwent modified radical mastectomy under general anesthesia. She is very anxious preoperatively. What monitor anesthetist might have used during surgery so that she does not remember anything intraoperative event.

Monitors used to assess depth of anesthesia: Electroencephalography (EEG) Bispectral index (BIS) Entropy Evoked responses (EP) - Motor EP, sensory EP (Auditory, visual, brain stem evoked potential) Patient safety index Narcotrend The bispectral index (BIS) is an empirically derived scale which helps to monitor the depth of anesthesia and intraoperative awareness. It processes the EEG and provides an index value between 0 and 100 that indicates the patient's level of consciousness. BIS index values range: 100 - Awake (Responds to normal voice) 0 - Flatline EEG (Deep coma) Recommended range of BIS index values for anesthesia- 40-60.