title: The human burst suppression electroencephalogram of deep hypothermia.
abstract: OBJECTIVE
  Deep hypothermia induces 'burst suppression' (BS), an electroencephalogram pattern with low-voltage 'suppressions' alternating with high-voltage 'bursts'. Current understanding of BS comes mainly from anesthesia studies, while hypothermia-induced BS has received little study. We set out to investigate the electroencephalogram changes induced by cooling the human brain through increasing depths of BS through isoelectricity.
  
  
  METHODS
  We recorded scalp electroencephalograms from eleven patients undergoing deep hypothermia during cardiac surgery with complete circulatory arrest, and analyzed these using methods of spectral analysis.
  
  
  RESULTS
  Within patients, the depth of BS systematically depends on the depth of hypothermia, though responses vary between patients except at temperature extremes. With decreasing temperature, burst lengths increase, and burst amplitudes and lengths decrease, while the spectral content of bursts remains constant.
  
  
  CONCLUSIONS
  These findings support an existing theoretical model in which the common mechanism of burst suppression across diverse etiologies is the cyclical diffuse depletion of metabolic resources, and suggest the new hypothesis of local micro-network dropout to explain decreasing burst amplitudes at lower temperatures.
  
  
  CONCLUSIONS
  These results pave the way for accurate noninvasive tracking of brain metabolic state during surgical procedures under deep hypothermia, and suggest new testable predictions about the network mechanisms underlying burst suppression.
authors: Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.|Department of Neurology, Harvard Medical School, Boston, MA, USA.
authors: M Brandon
authors: MB
authors: Westover
authors: Electrical and Systems Engineering, Washington University in St. Louis, St. Louis MO 63130, USA.
authors: Shinung
authors: S
authors: Ching
authors: Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.
authors: Vishakhadatta M
authors: VM
authors: Kumaraswamy
authors: Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA.
authors: Seun Oluwaseun
authors: SO
authors: Akeju
authors: Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA.|Department of Anaesthesiology, Harvard Medical School, Boston, MA, USA.
authors: Eric
authors: E
authors: Pierce
authors: Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.|Department of Neurology, Harvard Medical School, Boston, MA, USA.
authors: Sydney S
authors: SS
authors: Cash
authors: Department of Neurology, Beaumont Hospital, Dublin, Ireland.
authors: Ronan
authors: R
authors: Kilbride
authors: Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA.|Department of Anaesthesiology, Harvard Medical School, Boston, MA, USA.|Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
authors: Emery N
authors: EN
authors: Brown
authors: Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA.|Department of Anaesthesiology, Harvard Medical School, Boston, MA, USA.|Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
authors: Patrick L
authors: PL
authors: Purdon
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D007036:Hypothermia, Induced / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D012189:Retrospective Studies
keywords: Burst suppression; Electroencephalogram; Hypothermia
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