title: Relationship of bispectral index to minimum alveolar concentration during isoflurane, sevoflurane or desflurane anaesthesia.
abstract: OBJECTIVE
  To determine bispectral index (BIS) values produced by equipotent concentrations of commonly used volatile anaesthetics.
  
  
  METHODS
  Female patients undergoing thyroidectomy were randomly assigned to receive isoflurane, sevoflurane or desflurane anaesthesia. After induction, anaesthesia was maintained by the volatile agent at 1 minimum alveolar concentration and supplemented with remifentanil infusion. BIS values were recorded during 1 h surgical anaesthesia after a 15 min equilibrium phase.
  
  
  RESULTS
  Time-averaged BIS value during the study period was significantly lower in the desflurane group (n = 29) than the sevoflurane group (n = 27) (37.0 ± 4.9 vs 41.5 ± 5.9). Duration of deep hypnosis (BIS < 40) was significantly longer in the desflurane group than the sevoflurane group (40.2 ± 20.7 vs 24.3 ± 22.5 min). There were no significant differences in any parameter between the isoflurane group (n = 27) and any other group.
  
  
  CONCLUSIONS
  Desflurane produces a greater hypnotic effect than sevoflurane during equipotent anaesthesia. Management of volatile anaesthesia using predetermined minimum alveolar concentration targets can lead to an unnecessarily long duration of deep hypnosis.
authors.affiliation: Department of Anaesthesia and Pain Medicine, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Jin-Kyoung
authors.initials: JK
authors.lastname: Kim
authors.forename: Duk-Kyung
authors.initials: DK
authors.lastname: Kim
authors.forename: Myeong-Jin
authors.initials: MJ
authors.lastname: Lee
mesh_terms: D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000032:analysis*; D000077335:Desflurane; D005260:Female; D006801:Humans; D007530:Isoflurane / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000032:analysis*; D008738:Methyl Ethers / Q000008:administration & dosage / Q000032:analysis*; D011650:Pulmonary Alveoli / Q000737:chemistry*; D000077149:Sevoflurane; D013965:Thyroidectomy
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D000077335:Desflurane; D007530:Isoflurane
keywords: Bispectral index; desflurane; hypnosis; isoflurane; sevoflurane