title: Arterial blood and end-tidal concentrations of sevoflurane during the emergence from anesthesia in gynecologic patients.
abstract: OBJECTIVE
  The end-tidal concentration of inhalation anesthetics is a clinical indicator for predicting the emergence from anesthesia. This study was conducted to assess the relationship between arterial blood and end-tidal sevoflurane concentrations during emergence.
  
  
  METHODS
  Thirty-two female American Society of Anesthesiologists physical status I-II patients receiving general anesthesia for elective gynecologic surgery were included. A fixed dose of 3.5% inspiratory sevoflurane in 6 L min-1 oxygen was maintained until the end of surgery. At 20 and 10 minutes before and 0, 5, 10, 15, and 20 minutes after discontinuing sevoflurane, as well as at the time of eye opening by verbal command, defined as awakening, 1 ml arterial blood was obtained to measure its sevoflurane concentration by gas chromatography. Simultaneous inspiratory and end-tidal concentrations of sevoflurane were detected by an infrared analyzer and tested by Bland-Altman agreement analysis.
  
  
  RESULTS
  The arterial blood concentrations of sevoflurane were similar to the simultaneous end-tidal concentrations during emergence: 0.36% (0.10) and 0.36% (0.08) sevoflurane at awakening, respectively. The mean time from discontinuing sevoflurane to eye opening was 15.8 minutes (SD 2.9, range 10-26) and was significantly correlated with the duration of anesthesia (52-192 minutes) (P = 0.006) but not with the body mass index or total fentanyl dose.
  
  
  CONCLUSIONS
  The mean awakening arterial blood concentration of sevoflurane was 0.36%. The time to awakening was prolonged in accordance with the anesthetic duration within 3 hours. With well-assisted ventilation during emergence, the sevoflurane end-tidal concentration was nearly equal to its arterial blood concentration, which could be a feasible predictor for awakening.
authors.affiliation: Department of Anesthesiology, Tri-Service General Hospital/National Defense Medical Center, Taipei, Taiwan.
authors.forename: Tso-Chou
authors.initials: TC
authors.lastname: Lin
authors.affiliation: Department of Anesthesiology, Taipei Veterans General Hospital/National Defense Medical Center, Taipei, Taiwan.
authors.forename: Chih-Cherng
authors.initials: CC
authors.lastname: Lu
authors.affiliation: Department of Anesthesiology, Tri-Service General Hospital/National Defense Medical Center, Taipei, Taiwan.
authors.forename: Che-Hao
authors.initials: CH
authors.lastname: Hsu
authors.affiliation: Departments of Obstetrics and Gynecology, Tri-Service General Hospital/National Defense Medical Center, Taipei, Taiwan.
authors.forename: Her-Young
authors.initials: HY
authors.lastname: Su
authors.affiliation: School of Public Health, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Meei-Shyuan
authors.initials: MS
authors.lastname: Lee
authors.affiliation: Department of Anesthesiology, Taipei Veterans General Hospital/National Defense Medical Center, Taipei, Taiwan.
authors.forename: Shung-Tai
authors.initials: ST
authors.lastname: Ho
mesh_terms: D000328:Adult; D000762:Anesthesia Recovery Period; D000769:Anesthesia, Inhalation / Q000379:methods*; D000773:Anesthesia, Obstetrical / Q000379:methods*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000097:blood*; D001794:Blood Pressure / Q000187:drug effects; D015992:Body Mass Index; D002849:Chromatography, Gas; D004305:Dose-Response Relationship, Drug; D005260:Female; D013509:Gynecologic Surgical Procedures / Q000379:methods; D006439:Hemodynamics; D006801:Humans; D058926:Intraoperative Awareness; D008738:Methyl Ethers / Q000008:administration & dosage / Q000097:blood*; D008875:Middle Aged; D000077149:Sevoflurane; D013990:Tidal Volume / Q000187:drug effects; D013997:Time Factors; D055815:Young Adult
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane