title: Rapid 1% increases of end-tidal desflurane concentration to greater than 5% transiently increase heart rate and blood pressure in humans.
abstract: BACKGROUND
  Large (0.5-1.0 MAC), rapid increases of desflurane to concentrations greater than 5% can transiently increase heart rate, mean arterial blood pressure (MAP), sympathetic nerve activity, and plasma epinephrine concentration. We tested the hypothesis that small (1% = 0.14 MAC), rapid increases of desflurane concentration to greater than 5% do not increase heart rate, blood pressure, and plasma catecholamine concentrations.
  
  
  METHODS
  Anesthesia was induced with intravenous propofol, 2 mg/kg, in 13 healthy male volunteers, 19-33 yr of age, and ventilation was controlled to maintain normocapnia. We gave 4% end-tidal desflurane in oxygen for 32 min and then imposed successive 1% increases in end-tidal desflurane concentration, each new concentration maintained for 4 min, to a final concentration of 12%. We measured heart rate, MAP and plasma catecholamine concentrations in the awake state, after 4 min at each 1% step, and at times of peak increase of MAP (> or = 10% change).
  
  
  RESULTS
  Increases in heart rate and blood pressure of more than 10% occurred with 1% step-increases in only 1 volunteer at 5% desflurane but in 7-10 (MAP) and 8-12 (heart rate) of the 13 volunteers at higher desflurane concentrations. The 1% increases in desflurane concentration to greater than 5% also transiently increased plasma epinephrine concentrations but not vasopressin concentration or plasma renin activity in those volunteers in whom MAP increased.
  
  
  CONCLUSIONS
  Small (1%) increases in desflurane concentration to and greater than 6% can transiently increase heart rate, mean arterial pressure, and plasma epinephrine concentration. These data and those from a previous study indicate that these increases occur with a lesser frequency and magnitude than those associated with a single, rapid step from 4% to 12% end-tidal desflurane.
authors.affiliation: Department of Anesthesia, University of California, San Francisco 94143-0648.
authors.forename: M A
authors.initials: MA
authors.lastname: Moore
authors.forename: R B
authors.initials: RB
authors.lastname: Weiskopf
authors.forename: E I
authors.initials: EI
authors.lastname: Eger
authors.forename: M
authors.initials: M
authors.lastname: Noorani
authors.forename: L
authors.initials: L
authors.lastname: McKay
authors.forename: M
authors.initials: M
authors.lastname: Damask
mesh_terms: D000328:Adult; D001127:Arginine Vasopressin / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects*; D000077335:Desflurane; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000097:blood; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D007530:Isoflurane / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000494:pharmacology; D008168:Lung / Q000378:metabolism*; D008297:Male; D009638:Norepinephrine / Q000097:blood; D012083:Renin / Q000097:blood; D013268:Stimulation, Chemical; D013990:Tidal Volume
chemical_list: D001127:Arginine Vasopressin; D000077335:Desflurane; D007530:Isoflurane; D012083:Renin; D009638:Norepinephrine; D004837:Epinephrine