title: Age-dependency of sevoflurane-induced electroencephalogram dynamics in children.
abstract: BACKGROUND
  General anaesthesia induces highly structured oscillations in the electroencephalogram (EEG) in adults, but the anaesthesia-induced EEG in paediatric patients is less understood. Neural circuits undergo structural and functional transformations during development that might be reflected in anaesthesia-induced EEG oscillations. We therefore investigated age-related changes in the EEG during sevoflurane general anaesthesia in paediatric patients.
  
  
  METHODS
  We analysed the EEG recorded during routine care of patients between 0 and 28 yr of age (n=54), using power spectral and coherence methods. The power spectrum quantifies the energy in the EEG at each frequency, while the coherence measures the frequency-dependent correlation or synchronization between EEG signals at different scalp locations. We characterized the EEG as a function of age and within 5 age groups: <1 yr old (n=4), 1-6 yr old (n=12), >6-14 yr old (n=14), >14-21 yr old (n=11), >21-28 yr old (n=13).
  
  
  RESULTS
  EEG power significantly increased from infancy through ∼6 yr, subsequently declining to a plateau at approximately 21 yr. Alpha (8-13 Hz) coherence, a prominent EEG feature associated with sevoflurane-induced unconsciousness in adults, is absent in patients <1 yr.
  
  
  CONCLUSIONS
  Sevoflurane-induced EEG dynamics in children vary significantly as a function of age. These age-related dynamics likely reflect ongoing development within brain circuits that are modulated by sevoflurane. These readily observed paediatric-specific EEG signatures could be used to improve brain state monitoring in children receiving general anaesthesia.
authors.affiliation: Department of Anesthesia, Critical Care and Pain Medicine Harvard Medical School, Boston, MA, USA oluwaseun.akeju@mgh.harvard.edu patrickp@nmr.mgh.harvard.edu.
authors.forename: O
authors.initials: O
authors.lastname: Akeju
authors.affiliation: Department of Anesthesia, Critical Care and Pain Medicine.
authors.forename: K J
authors.initials: KJ
authors.lastname: Pavone
authors.affiliation: Harvard Medical School, Boston, MA, USA Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology.
authors.forename: J A
authors.initials: JA
authors.lastname: Thum
authors.affiliation: Department of Anesthesia, Critical Care and Pain Medicine Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.
authors.forename: P G
authors.initials: PG
authors.lastname: Firth
authors.affiliation: Department of Neurology, Massachusetts General Hospital, Boston, MA, USA Harvard Medical School, Boston, MA, USA.
authors.forename: M B
authors.initials: MB
authors.lastname: Westover
authors.affiliation: Department of Anesthesia, Critical Care and Pain Medicine Harvard Medical School, Boston, MA, USA.
authors.forename: M
authors.initials: M
authors.lastname: Puglia
authors.affiliation: Department of Anesthesia, Critical Care and Pain Medicine Harvard Medical School, Boston, MA, USA.
authors.forename: E S
authors.initials: ES
authors.lastname: Shank
authors.affiliation: Department of Anesthesia, Critical Care and Pain Medicine Harvard Medical School, Boston, MA, USA Department of Brain and Cognitive Science Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology Institute for Medical Engineering and Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
authors.forename: E N
authors.initials: EN
authors.lastname: Brown
authors.affiliation: Department of Anesthesia, Critical Care and Pain Medicine Harvard Medical School, Boston, MA, USA Department of Brain and Cognitive Science oluwaseun.akeju@mgh.harvard.edu patrickp@nmr.mgh.harvard.edu.
authors.forename: P L
authors.initials: PL
authors.lastname: Purdon
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography / Q000187:drug effects*; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology*; D000077149:Sevoflurane; D005680:gamma-Aminobutyric Acid / Q000502:physiology
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D005680:gamma-Aminobutyric Acid
keywords: electroencephalography; pediatric; sevoflurane