Bispectral index and anaesthesia in the elderly.

BACKGROUND

Due to pharmacokinetic and pharmacodynamic reasons, the elderly are at particular risk of incurring unwanted side effects of drugs commonly used in anaesthesia. The bispectral index (BIS) is an EEG-derived value that measures the sedative component of the anaesthetic state. The BIS could be useful in guiding titration of anaesthetic drugs in the elderly.

METHODS

A review of the published data was performed by the authors in order to assess the suitability of BIS technology application to the geriatric population.

RESULTS

Age-related EEG differences exist in the normal population but they do not affect the BIS. The BIS correlates with depth of sedation independently of age. Senile dementia may be associated with significantly lower BIS values.

CONCLUSIONS

The BIS is a useful guidance for titration of anaesthetic drugs in the elderly. The presence of senile dementia may be a confounding factor in the interpretation of the BIS values during anaesthesia.