Bispectral index monitoring involves the use of an electronic device that converts EEG waves into a number. This number, statistically derived from raw EEG data, indicates the depth or level of a patient’s sedation and provides a direct measure of the effects of sedatives and anesthetics on the brain. Rather than relying on subjective assessments and vital signs, bispectral index monitoring
provides objective, reliable data on which to base care, thus minimizing the risks of oversedation and undersedation. When used appropriately, bispectral index monitoring can decrease the total amount of sedation needed to keep a patient adequately sedated.

The bispectral index monitor is attached to a sensor applied to the patient’s forehead. The sensor obtains information about the patient’s electrical brain activity and then translates this information into a number from 0 (indicating no brain activity) to 100 (indicating a patient who’s awake and alert). In the critical care unit, bispectral index monitoring is used to assess sedation when the patient is receiving mechanical ventilation or neuromuscular blockers or during barbiturate coma or bedside procedures.