title: The effects of single-dose intravenous dexmedetomidine on hyperbaric bupivacaine spinal anesthesia.
abstract: OBJECTIVE
  Dexmedetomidine, a selective α2-adrenoceptor agonist, has analgesic and sedative effects. The purpose of this study was to investigate the effects of small, single-dose intravenous dexmedetomidine administration after hyperbaric bupivacaine spinal anesthesia.
  
  
  METHODS
  Sixty adult patients classified as American Society of Anesthesiologists physical status 1 or 2 and scheduled for lower extremity surgery under spinal anesthesia were studied. Patients were randomly assigned to one of three groups and administered hyperbaric intrathecal bupivacaine 12 mg. 5 min after spinal anesthesia, patients in groups 1, 2, and 3 received normal saline 10 ml, dexmedetomidine 0.25 μg/kg, and dexmedetomidine 0.5 μg/kg, respectively, over 10-min intravenous administration. The onset time, maximum block level, two-dermatome sensory regression time, duration of motor and sensory anesthesia, and side effects were assessed.
  
  
  RESULTS
  The two-dermatome sensory regression time was significantly increased in groups 2 and 3. The duration of motor and sensory anesthesia was significantly increased in group 3. Onset time, maximum block level, level of sedation, and incidence of hypotension and treatment-needed bradycardia were no different among the groups.
  
  
  CONCLUSIONS
  Single-dose intravenous dexmedetomidine 0.25-0.5 μg/kg, administered 5 min after intrathecal injection of hyperbaric bupivacaine, improved the duration of spinal anesthesia without significant side effects. This method may be useful for increasing the duration of spinal anesthesia, even after intrathecal injection of local anesthetics.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Seung Hwan
authors.initials: SH
authors.lastname: Jung
authors.forename: Soo Kyung
authors.initials: SK
authors.lastname: Lee
authors.forename: Kyung Jee
authors.initials: KJ
authors.lastname: Lim
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Park
authors.forename: Mae Hwa
authors.initials: MH
authors.lastname: Kang
authors.forename: Jung Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Jae Jun
authors.initials: JJ
authors.lastname: Lee
authors.forename: Sung Mi
authors.initials: SM
authors.lastname: Hwang
authors.forename: Sung Jun
authors.initials: SJ
authors.lastname: Hong
mesh_terms: D000328:Adult; D000775:Anesthesia, Spinal / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage; D002045:Bupivacaine / Q000008:administration & dosage*; D020927:Dexmedetomidine / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous / Q000379:methods; D007278:Injections, Spinal / Q000379:methods; D008297:Male; D008875:Middle Aged
chemical_list: D000779:Anesthetics, Local; D020927:Dexmedetomidine; D002045:Bupivacaine