Monitoring the anaesthetic depth in children - an update.

PURPOSE OF REVIEW There are several commercially available electroencephalogram-derived devices for monitoring anaesthesia depth. This article reviews all published studies describing their use in children; first assessing studies of performance in measuring anaesthesia depth in observational, physiological studies and then describing relevant outcome studies. There is also a brief discussion of why they might be useful, what physiological problems may arise and what the reader should be wary of in the methodology of these studies. The subject is approached from a clinical perspective. RECENT FINDINGS There are several physiological studies suggesting that for older children the bispectral index, entropy, Narcotrend index, cerebral state index and A-line ARX index all change with induction of anaesthesia, and have reasonable correlations with doses of anaesthetic agent. There is consistent evidence that the performances are substantially poorer in infants. Some of these devices have been demonstrated to reduce anaesthesia drug consumption and hasten recovery in older children. SUMMARY The bispectral index is the most widely studied, but at this stage there is no evidence to suggest any one device is substantially superior to any other. There may be a role emerging for their use in older children, but their use in infants cannot be supported.