ABSTRACT
BACKGROUND: P300 component of the long latency auditory evoked potentials (LLAEPs) provides information on conscious and cortical funtion. The P300 wave occures only for stimuli that somehow capture the patients attention. Therefore LLAEPs implys a degree of cognitive processing. We studied sedation scale and P300 wave to determine if LLAEPs could be utilized as electrophysiologic predictors of sedation. METHODS: The P300 component of LLAEPs from vertex was recorded from 10 ASA physical status I and II patients undergoing elective surgery while they listened via headphones to a series of clicks which were interrupted unpredictably by a tone burst (2 KHz) before and after diazepam 0.04 mg/kg and 0.08 mg/kg IV. The patients were asked to concentrate on the clicks and to press a button whenever they detected a 2 KHz tone. And sedation scale also was measured. RESULTS: Amplitude of P300 was decreased and latency of P300 was increased in a dose-dependent manner with IV diazepam. Amplitude was greatest and latency was shortest in awake. And sedation scale also was increased according to increased IV diazepam adminstration. CONCLUSIONS: Both amplitude and latency may be highly related to the sedation scale with progressively increasing dose of diazepam. Therefore we conclude that P300 component of LLAEPs can be utilized as an electrophysiologic predictor of awareness and sedation.