title: Assessing the depth of dexmedetomidine-induced sedation with electroencephalogram (EEG)-based spectral entropy.
abstract: BACKGROUND
  Adequate sedation of critically ill patients improves the outcome of intensive care. Maintaining an optimal level of sedation in the intensive care unit (ICU) is difficult because of a lack of appropriate monitoring methods to guide drug dosing. Dexmedetomidine, a selective alpha(2)-adrenoceptor agonist, has recently been introduced for the sedation of ICU patients. This study investigated the utility of electroencephalogram (EEG)-based spectral entropy monitoring (with M-ENTROPY, GE Healthcare, Helsinki, Finland) for the assessment of dexmedetomidine-induced sedation.
  
  
  METHODS
  Eleven healthy, non-smoking men, aged 23.9 +/- 2.5 years (mean +/- standard deviation), were recruited. Spectral entropy was recorded before and during low (0.5 ng/ml) and high (5 ng/ml) plasma concentrations of dexmedetomidine. At the end of the infusion, subjects were awakened by verbal command and light shaking.
  
  
  RESULTS
  Spectral entropy decreased from 84 +/- 5 to 66 +/- 16 (P= 0.029) during low dexmedetomidine levels and from 84 +/- 5 to 20 +/- 12 (P < 0.001) during high dexmedetomidine levels. Transitions during loss and regaining of consciousness were analysed separately. Entropy decreased from 76 +/- 8 before to 43 +/- 10 (P < 0.001) after loss of consciousness, and increased from 14 +/- 4 to 63 +/- 13 (P < 0.001) on regaining of consciousness. These changes were consistent across all subjects. Prediction probability and sensitivity values indicated a high predictive performance of the method.
  
  
  CONCLUSIONS
  The depth of dexmedetomidine-induced sedation can be monitored with EEG-based spectral entropy. These results should be confirmed in a clinical setting.
authors.affiliation: Turku PET Centre, University of Turku, Turku, Finland. Anu.Maksimow@utu.fi
authors.forename: A
authors.initials: A
authors.lastname: Maksimow
authors.forename: A
authors.initials: A
authors.lastname: Snapir
authors.forename: M
authors.initials: M
authors.lastname: Särkelä
authors.forename: E
authors.initials: E
authors.lastname: Kentala
authors.forename: J
authors.initials: J
authors.lastname: Koskenvuo
authors.forename: J
authors.initials: J
authors.lastname: Posti
authors.forename: S K
authors.initials: SK
authors.lastname: Jääskeläinen
authors.forename: S
authors.initials: S
authors.lastname: Hinkka-Yli-Salomäki
authors.forename: M
authors.initials: M
authors.lastname: Scheinin
authors.forename: H
authors.initials: H
authors.lastname: Scheinin
mesh_terms: D000328:Adult; D016292:Procedural Sedation; D003243:Consciousness; D003422:Critical Care; D020927:Dexmedetomidine / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography; D019277:Entropy; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage*; D008297:Male
chemical_list: D006993:Hypnotics and Sedatives; D020927:Dexmedetomidine