Changes In Information Processing In Propofol-induced Deep Sedation In Volunteers Using Electroencephalography  Teo Jeon Shin , Seongkeun Yoo; Pil-Jong Kim; Hong-Gee Kim (Dental Hospital - Yeon-Geon, Seoul National University, Seoul, Korea, Republic Of)   C20

We analyzed the effects of deep sedation with propofol on long latency components of the auditory event-related potential (ERP) in 20 normal volunteers (aged 26-30yr). ERP was elected though auditory passive odd pall paradigm in both the arousal and the sedative states for each volunteer. Electroencephalography (EEG) was recorded from 32 electrodes placed in the standard 10-20 International placement. To simulate the auditory passive odd ball paradigm, two different computer-generated auditory tones, an inter-stimulus of standard stimuli (p=0.8, n=400, 1000Hz) and a target oddball stimuli (p=0.2, n=100, 1200Hz) was presented via earphone. Sedative state was induced by intravenous propofol injection with a target controlled infusion syringe pump utilizing the Schnider model. Initial propofol concentration was (2.5 mg.kg-1. Propofol concentration was adjusted to maintain the bispectral index (BIS) value around 60. Acquired EEG data were categorized according to arousal and sedative state. Each epoched signals were averaged to individual ERPs. Two-dimensional topographic map was generated to visualize the differences. Channels within the regions showing statistically significant differences were selected for further analysis in temporal changes. In our study, we were able to verify a specific peak potential in the range of 320-360-ms, and 360-400-ms latency This peak signifies P300, an ERP component often elicited during simple discrimination tasks. P300 were especially evident in frontal and parietal areas. P300 signals showed statistically significant decrease after sedation. We conclude that P300 amplitude was profoundly affected by propofol given in sedative concentrations.