Extraction of BIS™ index sub-parameters in different anesthetic and sedative levels

Monitoring the depth of anesthesia is important to prevent undesirable events during surgery. According to direct effect of anesthetic drugs on synaptic activity of neurons and after presentation of anesthesia depth monitor (BIS) in 1996, there was a great interest on electroencephalogram analysis to investigate depth of anesthesia. Now there are large numbers of methods and algorithms in this field and every new method is compared with BIS index. BIS algorithm is based on three sub-parameters including time, frequency and higher order statistics domain parameters but the detailed algorithm is not in the public domain. In this paper, proper methods are presented for calculating three sub-parameters. Results of applying these methods to collected clinical data are presented. Efficiency of these methods was evaluated based on appropriate statistical analysis.