title: Performance of AEP Monitor/2-derived composite index as an indicator for depth of sedation with midazolam and alfentanil during gastrointestinal endoscopy.
abstract: OBJECTIVE
  The A-Line auditory evoked potential index (AAI) (AEP Monitor/2, Danmeter A/S, Odense, Denmark) is a newly developed composite parameter representing the degree of hypnosis. We conducted a prospective, observational study to explore the performance and validity of the AAI during conventional sedation for gastrointestinal (GI) endoscopy.
  
  
  METHODS
  Thirty adults of either sex, age <65, scheduled for combined oesophagogastroduodenoscopy (OGD) and colonoscopy under sedation with intravenous (i.v.) midazolam and alfentanil were enrolled. The sedative end-point was set at the Observer's Assessment of Alertness/Sedation (OAA/S) score less than 4. An AEP Monitor/2 was used in all patients. AAI, sedation scores, heart rate (HR), blood pressure (BP) and SPO2 were recorded every 2 min up to the end of the procedure. Receiver operator characteristic analysis was used to test validity and to select optimal sedation.
  
  
  RESULTS
  There was a significantly positive correlation between AAI and OAA/S scores (rho = 0.886; P < 0.001). The AAI also showed significant differences between subsequent levels of sedation scores (P < 0.001). AAI greater than 54 indicated fully awake or minimal sedation and values between 54 and 42 were suggestive of moderate sedation. Values between 42 and 34 were associated with moderate to deep sedation and readings below 34 were associated with deep sedation. The relative risk of SPO2 < 95% for OAA/S = 2 compared with 3 was 15.98 (95% confidence interval (CI): 3.94-64.81).
  
  
  CONCLUSIONS
  AAI is an effective tool for monitoring sedation during GI endoscopy induced by i.v. midazolam and alfentanil.
authors.affiliation: National Yang-Ming University, Taipei Veterans General Hospital & School of Medicine, Department of Anaesthesiology, Taiwan.
authors.forename: Y-Y
authors.initials: YY
authors.lastname: Huang
authors.forename: Y-C
authors.initials: YC
authors.lastname: Chu
authors.forename: K-Y
authors.initials: KY
authors.lastname: Chang
authors.forename: Y-C
authors.initials: YC
authors.lastname: Wang
authors.forename: K-H
authors.initials: KH
authors.lastname: Chan
authors.forename: M-Y
authors.initials: MY
authors.lastname: Tsou
mesh_terms: D000328:Adult; D015760:Alfentanil / Q000494:pharmacology*; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D016292:Procedural Sedation / Q000379:methods*; D016099:Endoscopy, Gastrointestinal / Q000379:methods*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008874:Midazolam / Q000494:pharmacology*; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation / Q000379:methods*; D010100:Oxygen / Q000097:blood; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D018686:Anesthetics, Intravenous; D015760:Alfentanil; D008874:Midazolam; D010100:Oxygen