Quantitative EEG changes associated with loss and return of consciousness in healthy adult volunteers anaesthetized with propofol or sevoflurane

• Published in: British journal of anaesthesia : BJA Vol. 87; no. 3; pp. 421 - 428
• Main Authors: Gugino, L.D., Chabot, R.J., Prichep, L.S., John, E.R., Formanek, V., Aglio, L.S.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.09.2001; Oxford University Press; Oxford Publishing Limited (England)
• Subjects: Adult; anaesthesia; anaesthesia, depth, conscious awareness; anaesthetics i.v; anaesthetics i.v., propofol; anaesthetics volatile; anaesthetics volatile, sevoflurane; Analysis of Variance; Anesthesia; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Anesthetics, Combined - pharmacology; Anesthetics, Inhalation - pharmacology; Anesthetics, Intravenous - pharmacology; Biological and medical sciences; brain; Brain Mapping - methods; brain, neurometrics; conscious awareness; Consciousness - drug effects; depth; Dose-Response Relationship, Drug; Electrodiagnosis. Electric activity recording; Electroencephalography - drug effects; Female; General anesthesia. Technics. Complications. Neuromuscular blocking. Premedication. Surgical preparation. Sedation; Humans; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Methyl Ethers - pharmacology; monitoring; Monitoring, Intraoperative - methods; monitoring, quantitative EEG; Nervous system; neurometrics; Piperidines - pharmacology; Premedication; propofol; Propofol - pharmacology; quantitative EEG; Remifentanil; Sevoflurane; anaesthetics i.v., propofol; anaesthetics volatile, sevoflurane; monitoring, quantitative EEG; anaesthesia, depth, conscious awareness; brain, neurometrics; monitoring, quantitative EEG; brain, neurometrics; anaesthetics i.v., propofol; anaesthetics volatile, sevoflurane; anaesthesia, depth, conscious awareness; Volatile compound; Human; Sevoflurane; General anesthetic; General anesthesia; Electroencephalography; Propofol; Monitoring; Quantitative analysis; Halogen Organic compounds
• ISSN: 0007-0912; 1471-6771
• DOI: 10.1093/bja/87.3.421

Significant changes in topographic quantitative EEG (QEEG) features were documented during induction and emergence from anaesthesia induced by the systematic administration of sevoflurane and propofol in combination with remifentanil. The goal was to identify those changes that were sensitive to alterations in the state of consciousness but independent of anaesthetic protocol. Healthy paid volunteers were anaesthetized and reawakened using propofol/remifentanil and sevoflurane/remifentanil, administered in graded steps while the level of arousal was measured. Alterations in the level of arousal were accompanied by significant QEEG changes, many of which were consistent across anaesthetic protocols. Light sedation was accompanied by decreased posterior alpha and increased frontal/central beta power. Frontal power predominance increased with deeper sedation, involving alpha and, to a lesser extent, delta and theta power. With loss of consciousness, delta and theta power increased further in anterior regions and also spread to posterior regions. These changes reversed with return to consciousness.