title: Frequency and clinical impact of preserved bispectral index activity during deep sedation in mechanically ventilated ICU patients.
abstract: OBJECTIVE
  Despite an overall correlation between the bispectral index of the EEG (BIS) and clinical sedation assessment, unexpectedly high BIS values can be observed at deep sedation levels. We assessed the frequency, interindividual variability and clinical impact of high BIS values during clinically deep sedation.
  
  
  METHODS
  Prospective observational study in two university-affiliated intensive care units.
  
  
  METHODS
  Sixty-two mechanically ventilated patients requiring intravenous sedation and analgesia for >or=24 h.
  
  
  RESULTS
  Paired measurements of BIS and sedation measured on the adaptation to intensive care environment (ATICE) score were obtained every 3 h until awakening. A paired measurement with BIS >60 at deep sedation (ATICE Awakeness <or=2) was defined as discordant. Patients were considered discordant if their individual ratio of number of discordant measurements to number of total measurements during deep sedation was above the median discordance ratio of the overall cohort. At least one discordant assessment was observed in 52 patients (83.9%). Median individual discordance ratio was 32% (14.3-50.0%). Time from awakening to first T-piece trial [16 h (4-34) vs. 46 h (9-109), p = 0.01] and to extubation [35 h (23-89) vs. 88 h (46-152 h), p = 0.05] were significantly shorter in discordant compared to concordant patients. BIS-ATICE discordance was independently associated with successful extubation within 48 h after awakening (OR 6.7, CI 95% 1.8-25.0, p = 0.005). The rate of ICU recall was not different in BIS-ATICE discordant and concordant patients.
  
  
  CONCLUSIONS
  In mechanically ventilated ICU patients, discordance between high BIS values and deep clinical sedation is frequently observed and may suggest faster weaning from the ventilator.
authors.affiliation: Department of Anaesthesiology and Critical Care, Beaujon University Hospital, Clichy, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Trouiller
authors.forename: Pascal
authors.initials: P
authors.lastname: Fangio
authors.forename: Catherine
authors.initials: C
authors.lastname: Paugam-Burtz
authors.forename: Corinne
authors.initials: C
authors.lastname: Appéré-de-Vecchi
authors.forename: Paul
authors.initials: P
authors.lastname: Merckx
authors.forename: Nicolas
authors.initials: N
authors.lastname: Louvet
authors.forename: Sebastian
authors.initials: S
authors.lastname: Pease
authors.forename: Hervé
authors.initials: H
authors.lastname: Outin
authors.forename: Jean
authors.initials: J
authors.lastname: Mantz
authors.forename: Bernard
authors.initials: B
authors.lastname: De Jonghe
mesh_terms: D000368:Aged; D054810:Deep Sedation / Q000145:classification*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000494:pharmacology; D007362:Intensive Care Units / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000187:drug effects; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000706:statistics & numerical data*; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D015300:Ventilator Weaning
chemical_list: D006993:Hypnotics and Sedatives