title: Optimal doses of sevoflurane and propofol in rabbits.
abstract: BACKGROUND
  Although sevoflurane and propofol are commonly used anesthetics in rabbits, optimal doses of remain unclear. We thus assessed the optimal hypnotic doses of sevoflurane and propofol, and evaluated the influence of dexmedetomidine on sevoflurane and propofol requirements.
  
  
  METHODS
  Twenty-eight Japanese white rabbits were randomly assigned to one of four groups (n=7 each). Rabbits were given either sevoflurane, propofol, sevoflurane+dexmedetomidine, or propofol+dexmedetomidine (injected 30 μg∙kg(-1)∙hr(-1) for 10 min followed by an infusion of 3.5 μg∙kg(-1)∙hr(-1)). Hypnotic level was evaluated with Bispectral Index (BIS), a well-validated electroenchalographic measure, with values between 40 and 60 representing optimal hypnosis. BIS measurements were made 10 minutes after the adjustment of target end-tidal sevoflurane concentration in the sevoflurane group and sevoflurane+dexmedetomidine group, and at 10 min after the change of infusion rate in the propofol group and propofol+dexmedetomidine group.
  
  
  RESULTS
  BIS values were linearly related to sevoflurane concentration and propofol infusion rate, with or without dexmedetomidine. Sevoflurane concentration at BIS=50 was 3.9±0.2% in the sevoflurane group and 2.6±0.3% in the sevoflurane+dexmedetomidine group. The propofol infusion rate to make BIS=50 was 102±5 mg∙kg(-1)∙hr(-1) in the propofol group, and 90±10 mg∙kg(-1)∙hr(-1) in the propofol+dexmedetomidine group.
  
  
  CONCLUSIONS
  The optimal end-tidal concentration of sevoflurane alone was thus 3.9%, and optimal infusion rate for propofol alone was 102 mg∙kg(-1)∙hr(-1). Dexmedetomidine reduced sevoflurane requirement by 33% and propofol requirement by 11%.
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Terada
authors.affiliation: Surgical Center, University of Yamanashi Hospital, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan. ishiyama@yamanashi.ac.jp.
authors.forename: Tadahiko
authors.initials: T
authors.lastname: Ishiyama
authors.forename: Nobumasa
authors.initials: N
authors.lastname: Asano
authors.forename: Masakazu
authors.initials: M
authors.lastname: Kotoda
authors.forename: Kodai
authors.initials: K
authors.lastname: Ikemoto
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Shintani
authors.forename: Daniel I
authors.initials: DI
authors.lastname: Sessler
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsukawa
mesh_terms: D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D056805:Consciousness Monitors; D020927:Dexmedetomidine / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D016014:Linear Models; D008738:Methyl Ethers / Q000008:administration & dosage* / Q000494:pharmacology*; D015742:Propofol / Q000008:administration & dosage* / Q000494:pharmacology*; D011817:Rabbits; D000077149:Sevoflurane; D013599:Systole / Q000187:drug effects
chemical_list: D008738:Methyl Ethers; D000077149:Sevoflurane; D020927:Dexmedetomidine; D015742:Propofol