title: Change in auditory evoked potential index and bispectral index during induction of anesthesia with anesthetic drugs.
abstract: The aim of this study was to evaluate the efficacy of the auditory evoked potential (AEP) index (aepEX) as an assessment tool for hypnosis during induction of various anesthetic drugs, and to compare its performance to that of the bispectral index (BIS). A total of 45 cases were divided into three groups based on the drugs used for anesthesia. Before anesthetic induction, BIS and AEP monitors were initiated. Anesthesia was induced through intravenous injection (IV) as follows: MP (n = 15) group, midazolam (0.1 mg/kg IV); TP (n = 15) group, thiopental (4 mg/kg IV); and KP (n = 15) group, ketamine (2 mg/kg IV). After loss of response (LOR), an infusion of 3 μg/ml propofol via a target-controlled infusion was initiated in all groups. AepEX and BIS were measured in the waking state (baseline) and at LOR (1 min after LOR), pre-intubation (1 min after previous intubation) and post-intubation (1 min after tracheal intubation finished). The value of aepEX significantly decreased in all groups with LOR and that of BIS also decreased except of KP group. No significant difference were observed in BIS values between baseline and LOR in the KS group. The aepEX might be more useful than BIS for hypnosis monitoring during anesthetic induction, particularly when drugs such as ketamine are used.
authors.affiliation: Department of Anesthesiology, Faculty of Medicine, Yamagata University, Iida-nishi 2-2-2, Yamagata-shi, Yamagata, 990-2323, Japan. matsusita-s@med.id.yamagata-u.ac.jp.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Matsushita
authors.affiliation: Department of Anesthesiology, Faculty of Medicine, Yamagata University, Iida-nishi 2-2-2, Yamagata-shi, Yamagata, 990-2323, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Oda
authors.affiliation: Department of Anesthesiology, Faculty of Medicine, Yamagata University, Iida-nishi 2-2-2, Yamagata-shi, Yamagata, 990-2323, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Otaki
authors.affiliation: Department of Anesthesiology, Faculty of Medicine, Yamagata University, Iida-nishi 2-2-2, Yamagata-shi, Yamagata, 990-2323, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Nakane
authors.affiliation: Department of Anesthesiology, Faculty of Medicine, Yamagata University, Iida-nishi 2-2-2, Yamagata-shi, Yamagata, 990-2323, Japan.
authors.forename: Kaneyuki
authors.initials: K
authors.lastname: Kawamae
mesh_terms: D000328:Adult; D000368:Aged; D018681:Anesthetics, General / Q000008:administration & dosage*; D003243:Consciousness / Q000187:drug effects*; D056805:Consciousness Monitors; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography / Q000187:drug effects / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D005260:Female; D006801:Humans; D064795:Intraoperative Neurophysiological Monitoring / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D018681:Anesthetics, General
keywords: Auditory evoked potential; Bispectral index; Depth of anesthesia monitors