title: Intravenous magnesium sulfate administration reduces propofol infusion requirements during maintenance of propofol-N2O anesthesia: part I: comparing propofol requirements according to hemodynamic responses: part II: comparing bispectral index in control and magnesium groups.
abstract: BACKGROUND
  The authors investigated whether an intravenous administration of magnesium sulfate reduces propofol infusion requirements during maintenance of propofol-N2O anesthesia.
  
  
  METHODS
  Part I study: 54 patients undergoing total abdominal hysterectomy were randomly divided into two groups (n = 27 per group). The patients in the control group received 0.9% sodium chloride solution, whereas the patients in the magnesium group received magnesium (50 mg/kg as a bolus, then 8 mg x kg(-1) x h(-1)). To maintain mean arterial blood pressure (MAP) and heart rate (HR) at baseline value, the propofol infusion rate was changed when the MAP or the HR changed. The amount of propofol infused excluding the bolus dosage was divided by patient's body weight and total infusion time. Part II study: Another 20 patients were randomly divided into two groups (n = 10 per group). When the MAP and HR had been maintained at baseline value and the propofol infusion rate had been maintained at 80 microg x kg(-1) x min(-1) (magnesium group) and 160 microg x kg(-1) x min(-1) (control group), bispectral index (BIS) values were measured.
  
  
  RESULTS
  Part I: The mean propofol infusion rate in the magnesium group (81.81 +/- 13.09 microg x kg(-1) x min(-1)) was significantly less than in the control group (167.57 +/- 47.27). Part II: BIS values in the control group (40.70 +/- 3.89) were significantly less than those in the magnesium group (57.80 +/- 7.32).
  
  
  CONCLUSIONS
  Intravenous administration of magnesium sulfate reduces propofol infusion requirements. These results suggest that magnesium administration may have an effect on anesthesia or analgesia and may be a useful adjunct to propofol anesthesia.
authors.affiliation: Department of Anesthesiology, Yonsei University Wonju College of Medicine, Kwangwon-Do, South Korea.
authors.forename: Jae Chan
authors.initials: JC
authors.lastname: Choi
authors.forename: Kyung Bong
authors.initials: KB
authors.lastname: Yoon
authors.forename: Dae Ja
authors.initials: DJ
authors.lastname: Um
authors.forename: Chan
authors.initials: C
authors.lastname: Kim
authors.forename: Jin Soo
authors.initials: JS
authors.lastname: Kim
authors.forename: Sang Gyu
authors.initials: SG
authors.lastname: Lee
mesh_terms: D000328:Adult; D000758:Anesthesia; D001794:Blood Pressure / Q000187:drug effects*; D004569:Electroencephalography / Q000187:drug effects*; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008278:Magnesium Sulfate / Q000494:pharmacology*; D009609:Nitrous Oxide / Q000494:pharmacology*; D015742:Propofol / Q000494:pharmacology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate; D008278:Magnesium Sulfate; D009609:Nitrous Oxide; D015742:Propofol