title: Cerebral state monitoring in Beagle dogs sedated with medetomidine.
abstract: OBJECTIVE
  To provide experience of monitoring the level of hypnosis with the Cerebral State Monitor (CSM), a device extracting a single numerical variable between 0 and 100 from the electroencephalogram in dogs sedated with medetomidine during dental scale removal.
  
  
  METHODS
  Prospective observational study. Animals Nine female Beagle dogs weighing 13.3 +/- 1.3 kg.
  
  
  METHODS
  Cerebral state index (CSI) and burst suppression ratio (BSR) were recorded from sub-dermal needle electrodes in dogs sedated after subcutaneous injection of 114 +/- 11 microg kg(-1) medetomidine. Ten minutes after injection CSI monitoring began, and after 5 minutes, dental scale removal with an ultrasonic probe was started. After approximately 30 minutes, the effects of medetomidine were antagonized with atipamezole.
  
  
  RESULTS
  The CSI had a median value of 43 (range 40-56) in undisturbed sedated dogs. During dental scale removal, CSI increased to a median value of 99 (range 92-100). The BSR in undisturbed sedated dogs ranged from 2 to 15, but fell to zero during dental scale removal.
  
  
  CONCLUSIONS
  Stimulation during dental scale removal might be expected to reduce the level of sedation and hypnosis in dogs to which medetomidine had been administered. The concurrent increase in CSI and decrease in BSR suggested that a higher CSI was associated with arousal from sedation and a reduction in the depth of hypnosis. More studies are needed to validate CSI in order to better understand the functioning of this monitor.
  
  
  CONCLUSIONS
  The CSM shows promise for monitoring the degree of sedation and hypnosis during anaesthesia, and after adequate validation, could contribute to the refinement of anaesthetic techniques in animals.
authors.affiliation: Biomedical Laboratory, University of Southern Denmark, Odense, Denmark. pbollen@health.sdu.dk
authors.forename: Peter J A
authors.initials: PJ
authors.lastname: Bollen
authors.forename: Henrik
authors.initials: H
authors.lastname: Saxtorph
mesh_terms: D000818:Animals; D016292:Procedural Sedation / Q000295:instrumentation / Q000662:veterinary*; D012534:Dental Scaling / Q000662:veterinary; D004285:Dogs / Q000502:physiology* / Q000601:surgery; D004569:Electroencephalography / Q000379:methods / Q000662:veterinary*; D005260:Female; D006993:Hypnotics and Sedatives / Q000008:administration & dosage*; D007279:Injections, Subcutaneous / Q000662:veterinary; D020926:Medetomidine / Q000008:administration & dosage*; D016343:Monitoring, Intraoperative / Q000662:veterinary; D011446:Prospective Studies; D012372:ROC Curve; D012815:Signal Processing, Computer-Assisted; D013687:Telencephalon / Q000187:drug effects / Q000502:physiology*
chemical_list: D006993:Hypnotics and Sedatives; D020926:Medetomidine