[Bispectral index (BIS)--a new ideology in solving an old problem]

A new method of electroencephalogram (EEG) processing is discussed: bispectral index (BIS), used for monitoring the depth of total anesthesia. The technology of BIS estimation is a principally novel approach to EEG processing, which can be denoted as an expert conclusion. EEG monitor Aspect A-100 (Aspect Medical System, USA) has been used for 3 years in the operation room during narcoses with barbiturates, propofol, midasolam, fentanyl, calypsol, isoflurane, and nitric oxide. BIS is a convenient and reliable method for evaluating the depth of total anesthesia with anesthetics with pronounced hypnotic effects at all stages of surgery. The disadvantages of the method are enumerated. The authors claim that monitors designed for expert evaluations hold good promise.