How useful is the bispectral index in the management of ICU patients?

If you want to objectively quantify the level of sedation the intuitive solution must be to monitor the brain directly. However, due to the complexity of this organ, and our limited understanding of consciousness, this remains a daunting challenge. For many years, researchers have investigated the electrical activity of the brain and its relationship with conscious level. Over the last few years, a derived variable from the EEG, the Bispectral Index (BIS), has been developed, which appears to correlate quite well with the level of pharmacological sedation.