title: [Measurement of the minimum alveolar concentration of sevoflurane during combined anesthesia with sevoflurane, small-dose dexmedetomidine and fentanyl].
abstract: OBJECTIVE
  To determine the minimum alveolar concentration (EC(50) and EC(95)) of sevoflurane in body movement response to surgical incision during combined anesthesia with dexmedetomidine, sevoflurane and fentanyl.
  
  
  METHODS
  Twenty-six ASA class I or II patients (aged 18-60 years) underwent selective surgery for lumbar disc herniation under general anesthesia with the combination of with dexmedetomidine, sevoflurane and fentanyl. All the patients received infusion with 0.5 mg/kg dexmedetomidine for 10 min before anesthesia induction with intravenous injection of 3 µg/kg fentanyl 8% sevoflurane inhalation. Upon loss of consciousness, sevoflurane concentration was reduced to 5% with intravenous injection of 1-2 mg/kg succinylcholine, and intubation was started after muscles relaxation. Anesthesia was maintained by sevoflurane and dexmedetomidine (0.2 µg·kg(-1)·h(-1)). Before the surgery, a steady state end-tidal sevoflurane concentration was maintained for at least 10 min. The first patient of the series was tested with 1.5% sevoflurane, and the concentration was adjusted according to modified Dixons up-and-down method (with a step size of 0.2%). Probit analysis was used for calculating EC(50), EC(95) and the 95% confidence interval (CI).
  
  
  RESULTS
  The EC(50) of sevoflurane was 0.94% (95%CI of 0.76%-1.07% ) and EC(95) was 1.23% (95%CI 1.09%-2.05% ).
  
  
  CONCLUSIONS
  The EC(50) and EC(95) of sevoflurane are 0.94% and 1.23%, respectively, for suppressing body movement in response to surgical incision during combined anesthesia with sevoflurane, dexmedetomidine and fentanyl.
authors.affiliation: Department of Anesthesiology, Guangzhou General Hospital of Guangzhou Command, Guangzhou 510010, China. cloudchen2008@163.com
authors.forename: Zhao-Yun
authors.initials: ZY
authors.lastname: Chen
authors.forename: Wei-Feng
authors.initials: WF
authors.lastname: Tu
authors.forename: Huan
authors.initials: H
authors.lastname: He
authors.forename: Jing-Xia
authors.initials: JX
authors.lastname: Huang
authors.forename: Chong
authors.initials: C
authors.lastname: Shi
mesh_terms: D000293:Adolescent; D000328:Adult; D000758:Anesthesia / Q000379:methods*; D000777:Anesthetics / Q000008:administration & dosage*; D020927:Dexmedetomidine / Q000008:administration & dosage*; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D008738:Methyl Ethers / Q000493:pharmacokinetics*; D008875:Middle Aged; D011650:Pulmonary Alveoli / Q000378:metabolism*; D012016:Reference Values; D000077149:Sevoflurane; D055815:Young Adult
chemical_list: D000777:Anesthetics; D008738:Methyl Ethers; D000077149:Sevoflurane; D020927:Dexmedetomidine; D005283:Fentanyl