Clinical applications of cerebral monitoring.

Direct cerebral monitoring is not yet in routine use in the intensive care unit or the operating theatre, despite the brain's sensitivity to ischaemia, and the potentially devastating consequences. Instead, reliance is placed upon indirect indicators such as general physiological parameters and observation of reflexes such as pupillary size and reaction to light. Complexity in the collection of artefact-free data and in the interpretation of the encephalogram, in the presence of anaesthetic/sedative drugs has deterred its widespread use. However, modern methods of processing and integrating data, (electroencephalographic/evoked potentials, haemodynamic and oxygen measures) together with the availability of powerful, robust microprocessors may well facilitate the development of on-line systems which can warn of cerebral deterioration. These would be of particular value in critically ill patients, and those at risk during or after operative procedures such as neurosurgery, cardiopulmonary bypass and carotid endarterectomy.