title: The effect of dexmedetomidine pretreatment on the median effective bolus dose of propofol for facilitating laryngeal mask airway insertion.
abstract: We designed this study to investigate the effect of dexmedetomidine (1 μg/kg) pretreatment on the median effective dose (ED50) of propofol for facilitating successful laryngeal mask airway (LMA) insertion compared to propofol alone.
  
  
  
  Forty patients were randomized to either the control group (n = 21) or the dexmedetomidine group (n = 19). After infusion of normal saline or dexmedetomidine 1 µg/kg over 10 min, 1 % lidocaine 0.5 mg/kg, followed by propofol 2.5 mg/kg was administered and the laryngeal mask airway was inserted without muscle relaxants. The ED50 of propofol for successful LMA insertion was determined by the modified Dixon's up-and-down method. The ED50 and ED95 were also calculated using an isotonic regression method, based on the pooled adjacent-violators algorithm-adjusted response rate, and the confidential interval (CI) was estimated using a bootstrap approach.
  
  
  
  The ED50 of propofol for smooth insertion of the LMA was significantly higher in the control group than in the dexmedetomidine group (3.1 ± 0.4 vs 1.9 ± 0.3 mg/kg, P < 0.001). From isotonic regression analysis using a bootstrap approach, the ED50 and ED95 of propofol was 2.9 mg/kg (83 % CI 2.5-3.3 mg/kg) and 3.9 mg/kg (95 % CI 3.5-4.0 mg/kg) in the control group, and 1.8 mg/kg (83 % CI 1.8-2.1 mg/kg) and 2.4 mg/kg (95 % CI 2.0-2.5 mg/kg) in the dexmedetomidine groups, respectively. The apnea time was not significantly different between the two groups.
  
  
  
  Pretreatment with dexmedetomidine 1 μg/kg could reduce the propofol requirement by 38 % for facilitating LMA insertion without prolonged respiratory depression and hemodynamic instability.
authors: Department of Anesthesiology and Pain Medicine, Ajou University School of Medicine, San 5, Wonchon-dong, Yeongtong-gu, Suwon, 443-721, Korea.
authors: Ji Young
authors: JY
authors: Yoo
authors: Department of Anesthesiology and Pain Medicine, Gachon University, Gil Medical Center, Incheon, Korea.
authors: Hyun Jeong
authors: HJ
authors: Kwak
authors: Department of Anesthesiology and Pain Medicine, Gachon University, Gil Medical Center, Incheon, Korea.
authors: Yong Beom
authors: YB
authors: Kim
authors: Department of Anesthesiology and Pain Medicine, Ajou University School of Medicine, San 5, Wonchon-dong, Yeongtong-gu, Suwon, 443-721, Korea.
authors: Chu Kyung
authors: CK
authors: Park
authors: Department of Anesthesiology and Pain Medicine, Ajou University School of Medicine, San 5, Wonchon-dong, Yeongtong-gu, Suwon, 443-721, Korea.
authors: Sook Young
authors: SY
authors: Lee
authors: Department of Anesthesiology and Pain Medicine, Ajou University School of Medicine, San 5, Wonchon-dong, Yeongtong-gu, Suwon, 443-721, Korea. kjyeop@ajou.ac.kr.
authors: Jong Yeop
authors: JY
authors: Kim
mesh_terms: D000328:Adult; D000368:Aged; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D000779:Anesthetics, Local; D001049:Apnea; D020927:Dexmedetomidine / Q000008:administration & dosage; D005260:Female; D006439:Hemodynamics; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D017214:Laryngeal Masks; D008012:Lidocaine; D008297:Male; D008875:Middle Aged; D015742:Propofol / Q000008:administration & dosage
chemical_list: D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D006993:Hypnotics and Sedatives; D020927:Dexmedetomidine; D008012:Lidocaine; D015742:Propofol
keywords: Dexmedetomidine; Laryngeal mask airway; Propofol