MONITORING DEPTH OF ANESTHESIA

In clinical practice, indirect and non-specific signs are used for mon itoring anaesthetic adequacy. These include haemodynamic, respiratory, muscular and autonomic signs. These measures do not indicate adequacy of anaesthesia in a reliable manner. Many attempts have been made to find a more accurate monitor. Direct monitoring of anaesthetic effect should be possible by EEG measurement. EEG information can be reduced, condensed and simplified, leading to single numbers (spectral edge fr equency and median frequency). These methods appear insufficient for a ssessing anaesthetic adequacy. The bispectral index, derived from bisp ectral analysis of the EEG, is a very promising tool for measuring ade quacy of anaesthesia. An alternative approach is to monitor evoked pot entials. Middle latency auditory evoked potentials may be helpful in a ssessing anaesthetic adequacy. Both techniques need further validation .