title: [BIS monitoring is useful for reliable intraoperative cortical mapping during brain tumor operations].
abstract: Poor detection of muscle motor evoked potential (m-MEP) by electrical cortical stimulation has often been encountered during neurosurgical operations, although widely known optimal factors for reliable detection have been put into practice. We hypothesized that the depth of anesthesia influenced the detection of m-MEP. Bispectral Index (BIS) monitoring was used to assess the depth of anesthesia for 16 patients during brain tumor operations. The doses of intravenous anesthetics, propofol, were titrated according to BIS indices during operations. When BIS indices were 40 or below, detection was difficult and higher intensities of electrical stimulation were necessary to evoke m-MEPs. Furthermore, risk of seizure was relatively high due to stronger electrical stimulation. Our results suggested that a BIS index above 50 and below 70 was optimal range. BIS monitoring is a useful method for setting the optimal dose of anesthetics for reliable intraoperative cortical mapping.
authors.affiliation: Department of Neurosurgery, Nippon Medical School (NMS) Main Hospital, Tokyo, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Yamaguchi
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Oi
authors.forename: Wataru
authors.initials: W
authors.lastname: Aoki
authors.forename: Rie
authors.initials: R
authors.lastname: Nakamura
authors.forename: Aki
authors.initials: A
authors.lastname: Igarashi
authors.forename: Minoru
authors.initials: M
authors.lastname: Kubota
authors.forename: Keiko
authors.initials: K
authors.lastname: Sawada
authors.forename: Toshiro
authors.initials: T
authors.lastname: Shimura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takahashi
authors.forename: Shiro
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Akira
authors.initials: A
authors.lastname: Teramoto
mesh_terms: D000328:Adult; D000368:Aged; D000771:Anesthesia, Intravenous; D018686:Anesthetics, Intravenous; D001931:Brain Mapping; D001932:Brain Neoplasms / Q000503:physiopathology / Q000601:surgery*; D002540:Cerebral Cortex / Q000503:physiopathology*; D004576:Electromyography; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D015742:Propofol
chemical_list: D018686:Anesthetics, Intravenous; D015742:Propofol