Bispectral Index (BIS)
The Bispectral Index (BIS) is a processed EEG parameter (0-100) measuring anaesthetic depth. Target for general anaesthesia is 40-60. It reduces awareness risk in high-risk patients, guides TIVA, and may aid recovery. BIS is affected by EMG, hypothermia, hypotension, and ketamine. It measures hypnosis, not analgesia. Anaesthesia trainees must interpret BIS alongside clinical signs.
