Differential dynamic of action on cortical and subcortical structures of anesthetic agents during induction of anesthesia.
BACKGROUND
Dynamic action of anesthetic agents was compared at cortical and subcortical levels during induction of anesthesia. Unconsciousness involved the cortical brain but suppression of movement in response to noxious stimuli was mediated through subcortical structures.


METHODS
Twenty-five patients with Parkinson disease, previously implanted with a deep-brain stimulation electrode, were enrolled during the implantation of the definitive pulse generator. During induction of anesthesia with propofol (n = 13) or sevoflurane (n = 12) alone, cortical (EEG) and subcortical (ESCoG) electrogenesis were obtained, respectively, from a frontal montage (F3-C3) and through the deep-brain electrode (p0-p3). In EEG and ESCoG spectral analysis, spectral edge (90%) frequency, median power frequency, and nonlinear analysis dimensional activation calculations were determined.


RESULTS
Sevoflurane and propofol decreased EEG and ESCoG activity in a dose-related fashion. EEG values decreased dramatically at loss of consciousness, whereas there was little change in ESCoG values. Quantitative parameters derived from EEG but not from ESCoG were able to predict consciousness versus unconsciousness. Conversely, quantitative parameters derived from ESCoG but not from EEG were able to predict movement in response to laryngoscopy.


CONCLUSIONS
These data suggest that in humans, unconsciousness mainly involves the cortical brain, but that suppression of movement in response to noxious stimuli is mediated through the effect of anesthetic agents on subcortical structures.
Velly
Lionel J
LJ
Department of Anesthesiology, Centre Hospitalier Universitaire Timone, Université de la Méditerranée, Marseille, France.
Rey
Marc F
MF
Bruder
Nicolas J
NJ
Gouvitsos
François A
FA
Witjas
Tatiana
T
Regis
Jean Marie
JM
Peragut
Jean Claude
JC
Gouin
François M
FM
D000368:Aged; D000758:Anesthesia / Q000379:methods*; D000777:Anesthetics / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000187:drug effects*; D003243:Consciousness / Q000187:drug effects; D046690:Deep Brain Stimulation / Q000379:methods; D004305:Dose-Response Relationship, Drug; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000187:drug effects* / Q000379:methods; D005260:Female; D006801:Humans; D007828:Laryngoscopy / Q000379:methods; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D009068:Movement / Q000187:drug effects; D010300:Parkinson Disease / Q000628:therapy*; D011237:Predictive Value of Tests; D015742:Propofol / Q000494:pharmacology; D011446:Prospective Studies; D012372:ROC Curve; D000077149:Sevoflurane; D020531:Subthalamic Nucleus / Q000187:drug effects*
D000777:Anesthetics; D008738:Methyl Ethers; D000077149:Sevoflurane; D015742:Propofol