title: The effect of dexmedetomidine on the adjuvant propofol requirement and intraoperative hemodynamics during remifentanil-based anesthesia.
abstract: BACKGROUND
  The effects of dexmedetomidine on the propofol-sparing effect and intraoperative hemodynamics during remifentanil-based propofol-supplemented anesthesia have not been well investigated.
  
  
  METHODS
  Twenty patients undergoing breast surgery were randomly allocated to receive dexmedetomidine (group DEX) or placebo (group C). In the DEX group, dexmedetomidine was loaded (1 µg/kg) before anesthesia induction and was infused (0.6 µg/kg/h) during surgery. Anesthesia was induced with a target-controlled infusion (TCI) of propofol (effect site concentration, Ce; 3 µg/ml) and remifentanil (plasma concentration, Cp, 10 ng/ml). The Ce of TCI-propofol was adjusted to a bispectral index of 45-55, and Cp of TCI-remifentanil was fixed at 10 ng/ml in both groups. Mean arterial blood pressure (MAP) and heart rate (HR) were recorded at baseline (T-control), after the loading of study drugs (T-loading), 3 min after anesthesia induction (T-induction), tracheal intubation (T-trachea), incision (T-incision), 30 min after incision (T-incision30), and at tracheal extubation (T-extubation). MAP% and HR% (MAP and HR vs. T-control) were determined and the propofol infusion rate was calculated.
  
  
  RESULTS
  The propofol infusion rate was significantly lower in the DEX group than in group C (63.9 ± 16.2 vs. 96.4 ± 10.0 µg/kg/min, respectively; P < 0.001). The changes in MAP% at T-induction, T-trachea and T-incision in group DEX (-10.0 ± 3.9%, -9.4 ± 4.6% and -11.2 ± 6.3%, respectively) were significantly less than those in group C (-27.6 ± 13.9%, -21.7 ± 17.1%, and -25.1 ± 14.1%; P < 0.05, respectively).
  
  
  CONCLUSIONS
  Dexmedetomidine reduced the propofol requirement for remifentanil-based anesthesia while producing more stable intraoperative hemodynamics.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: Woon-Seok
authors.initials: WS
authors.lastname: Kang
authors.forename: Sung-Yun
authors.initials: SY
authors.lastname: Kim
authors.forename: Jong-Chan
authors.initials: JC
authors.lastname: Son
authors.forename: Ju-Deok
authors.initials: JD
authors.lastname: Kim
authors.forename: Hasmizy Bin
authors.initials: HB
authors.lastname: Muhammad
authors.forename: Seong-Hyop
authors.initials: SH
authors.lastname: Kim
authors.forename: Tae-Gyoon
authors.initials: TG
authors.lastname: Yoon
authors.forename: Tae-Yop
authors.initials: TY
authors.lastname: Kim