title: The Alaris auditory evoked potential monitor as an indicator of seizure inducibility and duration during electroconvulsive therapy: an observational study.
abstract: BACKGROUND
  Precise control of anesthetic depth during electroconvulsive therapy (ECT) is crucial because most intravenous anesthetics have anticonvulsant effects. In this study, we investigated the association between anesthetic depth measured by the Alaris auditory evoked potential index (AAI) and seizure inducibility and seizure duration during ECT.
  
  
  METHODS
  Sixty-four ECTs were evaluated in 12 consecutive patients. General anesthesia was performed with a thiopental-based method. The relationship between the pre-ictal AAI, seizure activity and seizure duration was analyzed, and a possible threshold pre-ictal AAI to induce a seizure duration of at least 25 seconds was calculated.
  
  
  RESULTS
  Forty-one of the 64 ECT stimuli successfully induced seizure activity that lasted longer than 25 seconds. Pre-ictal AAI was significantly correlated to seizure duration (r = 0.54, p < 0.001) and the threshold pre-ictal AAi value was calculated to be 26 (area under curve: 0.76, sensitivity: 70.3% and specificity: 73.9%, p < 0.001). ECT with a pre-ictal AAI ≧ 26 had a higher incidence of successful seizure activity ( p < 0.001) and a longer seizure duration (55 ± 35 v.s. 21 ± 27 seconds, p < 0.001).
  
  
  CONCLUSIONS
  Maintenance of a pre-ictal AAI value ≧ 26 was associated with an increased incidence of successful seizure activities and a longer seizure duration. This is the first report to investigate Alaris AEP monitoring during ECT.
authors.affiliation: Department of Anesthesiology, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 10002, Taiwan.
authors.forename: Hsing-Hao
authors.initials: HH
authors.lastname: Huang
authors.affiliation: Department of Anesthesiology, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 10002, Taiwan.
authors.forename: Chun-Yu
authors.initials: CY
authors.lastname: Wu
authors.affiliation: Department of Anesthesiology, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 10002, Taiwan.
authors.forename: Feng-Sheng
authors.initials: FS
authors.lastname: Lin
authors.affiliation: Department of Anesthesiology, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 10002, Taiwan.
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Wang
authors.affiliation: Department of Anesthesiology, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 10002, Taiwan.
authors.forename: Wei-Zen
authors.initials: WZ
authors.lastname: Sun
authors.affiliation: Department of Anesthesiology, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 10002, Taiwan ; Department of Pharmacology, College of Medicine, National Taiwan University, No. 1 Sec. 1, Jen-Ai Road, Taipei 100, Taiwan.
authors.forename: Chih-Peng
authors.initials: CP
authors.lastname: Lin
authors.affiliation: Department of Anesthesiology, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 10002, Taiwan.
authors.forename: Shou-Zen
authors.initials: SZ
authors.lastname: Fan
mesh_terms: D000328:Adult; D000768:Anesthesia, General / Q000379:methods; D018686:Anesthetics, Intravenous / Q000008:administration & dosage* / Q000494:pharmacology; D004565:Electroconvulsive Therapy / Q000379:methods*; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012640:Seizures / Q000378:metabolism*; D013874:Thiopental / Q000008:administration & dosage / Q000494:pharmacology; D013997:Time Factors
chemical_list: D018686:Anesthetics, Intravenous; D013874:Thiopental
keywords: Auditory evoked potential; Electroconvulsive therapy; Seizure inducibility