Artifact in the bispectral index in a patient with severe ischemic brain injury

Abstract

The electroencephalogram (EEG) has been used to predict neurological outcome in patients with anoxic-ischemic brain injury. The bispectral index (BIS) may be a useful alternative. A persistently low BIS associated with burst-suppression of the raw EEG in the setting of minimal hypnotic drug administration may indicate severe cerebral ischemia. We report a case where a patient with presumed ischemic brain injury and an extremely low BIS had an unexplained increase in BIS that could be attributed to electrocardiogram artifact. Care should be taken when interpreting BIS in the setting of anoxic-ischemic brain injury or brain death.

Implications: The bispectral index (BIS) can be prone to artifact. In this report we found that electrocardiogram artifact led to an apparent normal BIS in a patient with complete burst-suppression associated with severe brain injury.