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Entropy during propofol hypnosis, including an episode of wakefulness
Author(s) -
Anderson R. E.,
Barr G.,
Öwall A.,
Jakobsson Jan
Publication year - 2004
Publication title -
anaesthesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.839
H-Index - 117
eISSN - 1365-2044
pISSN - 0003-2409
DOI - 10.1111/j.1365-2044.2004.03523.x
Subject(s) - wakefulness , propofol , medicine , hypnosis , anesthesia , alertness , sedation , hypnotic , electroencephalography , audiology , psychiatry , alternative medicine , pathology
Depth of anaesthesia has proved to be a complex process to quantify. Monitors based on bispectral analysis of the electroencephalogram and auditory evoked potential have been available, but only recently has a monitor based on entropy become available. This study determined state entropy and response entropy in nine healthy volunteers during propofol hypnosis with a brief intervening period of wakefulness. Both the calculated entropy indices decreased with increasing levels of sedation ( r 2 = 0.58 and 0.61, respectively) and they showed a high correlation with each other ( r 2 = 0.94). However, an overlap was observed in real time indices between different stages of the Observer's Assessment of Alertness/Sedation Scale. Only three of the nine volunteers had explicit memories from the episode of wakefulness. Electroencephalographic entropy monitors seem to have potential for staging clinical hypnotic effects.