Validation of the Brain Anaesthesia Response (BAR) Monitoring System during Anaesthesia for Cardiac Surgery: a Double-Blinded, Randomised, Controlled Trial using Two Different Doses of Fentanyl.

The Brain Anaesthesia Response (BAR) monitor system is designed to non-invasively monitor brain function in response to anaesthetic and sedative agents. Electroencephalography (EEG) signals are collected using the sensor which is applied to the patients’ forehead. The signals are processed to calculate two BAR indices, Cortical State (CS) and Cortical Input (CI). The displayed indices are designed to assist the anaesthetist to estimate the levels of consciousness and analgesia of a patient during general anaesthesia. The study is designed to investigate whether the BAR indices recorded in the operating room environment can distinguish between two groups of patients anaesthetised with either a low or a moderate dose of fentanyl and show clinically meaningful correlations with levels of hypnosis.