title: The effect of dexmedetomidine on perioperative hemodynamics in patients undergoing craniotomy.
abstract: BACKGROUND
  The perioperative course of patients undergoing intracranial surgery is frequently complicated by hypertensive episodes. Dexmedetomidine (DEX), an alpha-2 adrenoreceptor agonist, is gaining popularity in neuroanesthesia, because its sympatholytic and antinociceptive properties may improve hemodynamic stability at critical moments of surgery. We designed this study to assess the efficacy of DEX in controlling hypertensive responses in patients undergoing intracranial surgery.
  
  
  METHODS
  Patients scheduled for elective craniotomy were randomly assigned to receive either sevoflurane-opioid or sevoflurane-opioid-DEX anesthesia. Bispectral index was used to maintain a similar level of hypnosis in both groups (40-50). Opioids, sevoflurane, and vasoactive medications were titrated in a routine manner, at the discretion of the blinded anesthesiologist managing the case, to maintain systolic blood pressure (SBP) targeted within 90-130 mm Hg and heart rate (HR) between 50 and 90 bpm. Hemodynamic variables were continuously recorded and stored on a computer for analysis. Efficacy of the anesthetic technique in controlling SBP or HR is inversely proportional to the area under the curve (AUC) outside the targeted range. Areas under the curves above and below targeted ranges for SBP-time (AUCsbp mm Hg*min/h) and HR-time (bpm*min/h) were compared. Coefficient of variation was used to assess hemodynamic stability.
  
  
  RESULTS
  Seventy-two patients were recruited for the study. Computerized records of 56 patients only were analyzed because of technical problems with data collection in 14 cases. AUCsbp for above the targeted range was significantly lower for patients in the DEX group (P=0.044). The coefficient of variation for SBP or HR did not differ between groups. A significantly smaller proportion of patients in the DEX group required treatment with antihypertensive medications (12 of 28, 42% vs 24 of 28, 86%, P=0.0008). The DEX group required fewer opioids in the intraoperative period, but there were no differences in the use of sevoflurane. In the postanesthesia care unit, patients in the DEX group had fewer hypertensive episodes (1.25+/-1.55 vs 2.50+/-2.00, P=0.0114) and were discharged earlier (91+/-17 vs 130+/-27 min, P<0.0001). There were no differences in the requirement for postoperative opioids or antiemetics.
  
  
  CONCLUSIONS
  By using indices, which assess a global hemodynamic stability of the anesthetic, we determined that intraoperative DEX infusion was effective for blunting the increases in SBP perioperatively. The use of DEX did not increase the incidence of hypotension or bradycardia, common side effects of the drug.
authors.affiliation: Department of Anesthesiology, New York University Medical Center, 560 First Ave., New York, NY 10016, USA. alexbekker@med.nyu.edu
authors.forename: Alex
authors.initials: A
authors.lastname: Bekker
authors.forename: Mary
authors.initials: M
authors.lastname: Sturaitis
authors.forename: Marc
authors.initials: M
authors.lastname: Bloom
authors.forename: Mario
authors.initials: M
authors.lastname: Moric
authors.forename: John
authors.initials: J
authors.lastname: Golfinos
authors.forename: Erik
authors.initials: E
authors.lastname: Parker
authors.forename: Ramesh
authors.initials: R
authors.lastname: Babu
authors.forename: Abishabeck
authors.initials: A
authors.lastname: Pitti
mesh_terms: D000759:Adjuvants, Anesthesia / Q000008:administration & dosage; D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage*; D000328:Adult; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage*; D018685:Anesthetics, Inhalation; D001794:Blood Pressure / Q000187:drug effects*; D003399:Craniotomy; D020927:Dexmedetomidine / Q000008:administration & dosage*; D004311:Double-Blind Method; D004569:Electroencephalography; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D008738:Methyl Ethers; D008875:Middle Aged; D000077149:Sevoflurane
chemical_list: D000759:Adjuvants, Anesthesia; D000316:Adrenergic alpha-Agonists; D018712:Analgesics, Non-Narcotic; D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D020927:Dexmedetomidine