title: Use of bispectral index to monitor the depth of sedation in mechanically ventilated patients in the prehospital setting.
abstract: BACKGROUND
  Sedative drug administration is a challenging aspect of the management of mechanically ventilated patients in the out-of-hospital critical care medicine. We hypothesised that the bispectral index of the EEG (BIS) could be a helpful tool in evaluating the depth of sedation in this difficult environment. The main objective of the present study was to assess the agreement of BIS with the clinical scales in the out-of-hospital setting.
  
  
  METHODS
  This prospective study included mechanically ventilated patients. BIS values were blindly recorded continuously. A Ramsay score was performed every 5 min. The main judgement criterion was the correlation between BIS values and the Ramsay score.
  
  
  RESULTS
  72 patients were included, mostly presenting with toxic coma (36%) or neurological coma (21%). The median (IQR) BIS value was 85 (84-86) when the Ramsay score was 3, 80 (76-84) when the Ramsay score was 4, 61 (55-80) when the Ramsay score was 5 and 45 (38-60) when the Ramsay score was 6. According to Receiver operating characteristic (ROC) curves, BIS was categorised into three classes (BIS<54 corresponding to Ramsay score 6, 54≤BIS<72 for Ramsay score 5 and BIS≥73 for Ramsay score ≤4). Based on these categories, the proportion of appropriate BIS values was 67% (217/323). The concordance correlation coefficient for repeated measurements was 0.54 (0.43-0.64). The agreement between BIS and the Ramsay score is moderate.
  
  
  CONCLUSIONS
  Prehospital measured BIS values appear poorly correlated with clinical assessment of the depth of sedation. For this reason, the use of BIS to guide prehospital sedation cannot be recommended.
authors.affiliation: Emergency Medical Service Department, Beaujon University Hospital, Clichy, France.
authors.forename: François-Xavier
authors.initials: FX
authors.lastname: Duchateau
authors.affiliation: Emergency Medical Service Department, Beaujon University Hospital, Clichy, France.
authors.forename: Monique
authors.initials: M
authors.lastname: Saunier
authors.affiliation: Epidemiology and Clinical Research Unit, Beaujon University Hospital, Clichy, France.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Larroque
authors.affiliation: Emergency Medical Service Department, Beaujon University Hospital, Clichy, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Josseaume
authors.affiliation: Department of Anaesthesiology and Intensive Care, Beaujon University Hospital, Clichy, France.
authors.forename: Tobias
authors.initials: T
authors.lastname: Gauss
authors.affiliation: Emergency Medical Service Department, Beaujon University Hospital, Clichy, France.
authors.forename: Sonja
authors.initials: S
authors.lastname: Curac
authors.affiliation: Emergency Medical Service Department, Beaujon University Hospital, Clichy, France.
authors.forename: Estelle
authors.initials: E
authors.lastname: Wojciechowski-Bonnal
authors.affiliation: Department of Anaesthesiology and Intensive Care, Beaujon University Hospital, Clichy, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Mantz
mesh_terms: D000328:Adult; D000368:Aged; D016292:Procedural Sedation; D056805:Consciousness Monitors / Q000592:standards*; D004569:Electroencephalography / Q000379:methods*; D004632:Emergency Medical Services / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D011446:Prospective Studies; D012372:ROC Curve; D012121:Respiration, Artificial
chemical_list: D006993:Hypnotics and Sedatives
keywords: anaesthesia - general; prehospital care, critical care transport