title: Caudal dexmedetomidine decreases the required concentration of levobupivacaine for caudal block in pediatric patients: a randomized trial.
abstract: OBJECTIVE
  Dexmedetomidine (D) can prolong the duration of local anesthetics, but the effect of caudal dexmedetomidine on the potency of levobupivacaine (L) for caudal block has not been investigated. This study was designed to determine the effect of caudal dexmedetomidine on levobupivacaine for caudal block in pediatric patients.
  
  
  METHODS
  Eighty-nine children scheduled for elective inguinal hernia repair or hydrocele were randomly assigned to one of the three groups: Group L (caudal levobupivacaine), Group LD1 (levobupivacaine plus 1 μg·kg(-1) dexmedetomidine), or Group LD2 (levobupivacaine plus 2 μg·kg(-1) dexmedetomidine). The primary endpoint was the minimum local anesthetic concentration (MLAC), which was determined using the Dixon up-and-down method. The secondary endpoints were the duration of analgesia and sedation.
  
  
  RESULTS
  The MLAC values (sd) of caudal levobupivacaine were 0.103 (0.01)%, 0.068 (0.02)%, and 0.055 (0.03)% in Groups L, LD1, and LD2, respectively. The values of EC50 and EC95 (95% CI) of caudal levobupivacaine from logistic regression analysis were 0.094 (0.083-0.105)% and 0.129 (0.1-0.159)%, 0.058 (0.044-0.072)% and 0.106 (0.067-0.144)%, and 0.046 (0.033-0.059)% and 0.091 (0.055-0.127)% in Groups L, LD1, and LD2, respectively. The mean durations of analgesia in the postoperative period were 141, 378, and 412 min in Groups L, LD1, and LD2, respectively (L vs LD1 or LD2, P < 0.001). The mean durations of sedation in both Groups LD1 and LD2 also were significantly prolonged, compared with Group L (P < 0.01).
  
  
  CONCLUSIONS
  Caudal dexmedetomidine reduces the MLAC values of levobupivacaine and improves postoperative analgesia in children without any neurological side effects.
authors.affiliation: Department of Anesthesiology, Guangzhou Women and Children Medical Center, Guangzhou Medical University affiliated Women and Children Medical Center, Guangzhou, China.
authors.forename: Ying-Jun
authors.initials: YJ
authors.lastname: She
authors.forename: Zhi-Yi
authors.initials: ZY
authors.lastname: Zhang
authors.forename: Xing-Rong
authors.initials: XR
authors.lastname: Song
mesh_terms: D000759:Adjuvants, Anesthesia; D000698:Analgesia; D000763:Anesthesia, Caudal / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D002045:Bupivacaine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D002675:Child, Preschool; D016292:Procedural Sedation; D020927:Dexmedetomidine / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D023381:Endpoint Determination; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D007223:Infant; D000077554:Levobupivacaine; D008297:Male
chemical_list: D000759:Adjuvants, Anesthesia; D000779:Anesthetics, Local; D006993:Hypnotics and Sedatives; D020927:Dexmedetomidine; D000077554:Levobupivacaine; D002045:Bupivacaine
keywords: adjuvants, anesthesia; analgesia; anesthesia, caudal; anesthesia, local; dexmedetomidine; levobupivacaine