title: [Low doses of ketamine have no effect on bispectral index during stable propofol-remifentanil anesthesia].
abstract: BACKGROUND
  Ketamine is associated with an increase in the bispectral index (BIS) values that can lead to an overdose of hypnotic agents. We investigated the effect of ketamine on BIS values during general anesthesia with a target-controlled infusion (TCI) of propofol and infusion of remifentanil.
  
  
  METHODS
  Forty-five ASA I or II patients undergoing gynecological surgery were included in this study. After 5 min of steady-state anesthesia (BIS at 35-45) without surgical stimulation, patients received either a bolus administration of ketamine 0.2 mg x kg(-1) (LK group) or ketamine 0.5 mg x kg(-1) (HK group). Patients in the control group received no intervention. BIS values were recorded every minute until 15 min after ketamine administration.
  
  
  RESULTS
  After ketamine administration, BIS value in HK group increased significantly compared with that at baseline. There were no significant changes for BIS values in LK group and control group over time. BIS values in HK group were significantly higher than those in the LK group and control group after ketamine injection. BIS values were not statistically different between LK group and control group.
  
  
  CONCLUSIONS
  Under stable propofol and remifentanil anesthesia, a small dose of ketamine did not increase the BIS value over the next 15 min.
authors.affiliation: Department of Anesthesia, Yamanashi Prefectural Central Hospital, Kofu 400-8506.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Nonaka
authors.forename: Kenzo
authors.initials: K
authors.lastname: Makino
authors.forename: Satomi
authors.initials: S
authors.lastname: Suzuki
authors.forename: Kodai
authors.initials: K
authors.lastname: Ikemoto
authors.forename: Atsushi
authors.initials: A
authors.lastname: Furuya
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Tamaki
authors.forename: Nobumasa
authors.initials: N
authors.lastname: Asano
mesh_terms: D000082:Acetaminophen; D000768:Anesthesia, General; D018686:Anesthetics, Intravenous; D001241:Aspirin; D002744:Chlorpheniramine; D056805:Consciousness Monitors; D011431:Dextropropoxyphene; D004338:Drug Combinations; D005260:Female; D006801:Humans; D007649:Ketamine / Q000494:pharmacology*; D010880:Piperidines; D000077208:Remifentanil
chemical_list: D018686:Anesthetics, Intravenous; D004338:Drug Combinations; D010880:Piperidines; C004575:propofan; D000082:Acetaminophen; D002744:Chlorpheniramine; D007649:Ketamine; D000077208:Remifentanil; D001241:Aspirin; D011431:Dextropropoxyphene