title: Auditory evoked potentials compared with bispectral index for monitoring of midazolam and propofol sedation during colonoscopy.
abstract: OBJECTIVE
  The purpose of this study was to evaluate and compare Bispectral index (BIS) and A-line auditory evoked potential index (AAI) for monitoring depth of low-dose midazolam and propofol sedation during colonoscopy.
  
  
  METHODS
  A total of 115 consecutive patients (ASA I-IV), receiving low-dose midazolam and propofol sedation for colonoscopy, were evaluated. BIS and AAI levels, Observer's Assessment of Alertness/Sedation (OAA/S) scores, blood pressure, heart rate, oxygen saturation, as well as the presence or absence of eyelash reflex, patient reaction to an external noxious stimulus and to procedure-related pain were recorded every 1-3 min by a single trained observer.
  
  
  RESULTS
  There was a positive correlation between BIS and OAA/S scores (correlation coefficient=0.77) and to a lesser extent AAI and OAA/S scores (correlation coefficient=0.47). BIS and AAI showed significant differences between subsequent levels of sedation (P<0.001). The clustered receiver operating characteristic curve estimate of BIS for the detection of deep sedation was significantly better than that of AAI (P<0.001). Regarding the presence or absence of eyelash reflex and patient reaction to an external noxious stimulus and to procedure-related pain, significant different levels were found for BIS as well as AAI, respectively. Only small changes were observed in hemodynamic variables and oxygen saturation. Overall, our data suggest target BIS levels of slightly above 73 for moderate sedation (defined as OAA/S scores 2 and 3).
  
  
  CONCLUSIONS
  BIS and AAI correlated with the level of sedation. Hemodynamic variables were poor indicators of the hypnotic-anesthetic status of the patient. BIS discriminated best between moderate and deep sedation and could complement clinical observation for guidance of moderate sedation.
authors.affiliation: 12nd Medical Department, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: von Delius
authors.forename: Philipp
authors.initials: P
authors.lastname: Thies
authors.forename: Thomas
authors.initials: T
authors.lastname: Rieder
authors.forename: Stefan
authors.initials: S
authors.lastname: Wagenpfeil
authors.forename: Esther
authors.initials: E
authors.lastname: Herberich
authors.forename: Artemisia
authors.initials: A
authors.lastname: Karagianni
authors.forename: Eckart
authors.initials: E
authors.lastname: Frimberger
authors.forename: Alexander
authors.initials: A
authors.lastname: Meining
authors.forename: Leopold
authors.initials: L
authors.lastname: Ludwig
authors.forename: Matthias Pa
authors.initials: MP
authors.lastname: Ebert
authors.forename: Ewert
authors.initials: E
authors.lastname: Schulte-Frohlinde
authors.forename: Bruno
authors.initials: B
authors.lastname: Neu
authors.forename: Christian
authors.initials: C
authors.lastname: Prinz
authors.forename: Roland M
authors.initials: RM
authors.lastname: Schmid
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Huber
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001364:Awareness; D003113:Colonoscopy; D016292:Procedural Sedation; D003243:Consciousness; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives; D008297:Male; D008874:Midazolam; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D015742:Propofol; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D006993:Hypnotics and Sedatives; D008874:Midazolam; D015742:Propofol