title: Adding dexmedetomidine to ropivacaine for femoral nerve block inhibits local inflammatory response.
abstract: BACKGROUND
  Peripheral nerve block has an anti-inflammatory effect that is confirmed in animal studies, while inconclusive in human studies. Dexmedetomidine (DEX), a highly selective α2-adenoceptor agonist, has a potent anti-inflammatory effect. The aim of this study was to evaluate the effect of DEX added to ropivacaine for femoral nerve block (FNB) on local inflammatory response after total knee arthroplasty (TKA).
  
  
  METHODS
  Sixty patients scheduled for TKA were randomized into two equal groups in a prospective randomized study. They were all treated with FNB preoperatively. In group R, 20 mL of 0.5% ropivacaine were injected for the block; in group RD, 20 mL of 0.5% ropivacaine plus 1 µg/kg DEX were administered. Visual Analog Scale (VAS), the circumference of the operated knee, and the concentration of interleukin-6 (IL-6) and prostaglandin E2 (PGE2) in joint fluid were evaluated. Adverse events such as hypotension, bradycardia and hypoxia were recorded.
  
  
  RESULTS
  VAS was lower in group RD for 12 to 48 hours after surgery (P<0.03). Knee circumference was smaller in group RD at each time point after surgery (P<0.05). PGE2 in joint fluid in group RD was lower at 6, 12, 24, and 48 hours after surgery (P<0.02), IL-6 was lower at 12, 24, and 48 hours after surgery (P<0.03). No adverse events were observed.
  
  
  CONCLUSIONS
  Adding 1 µg/kg dexmedetomidine to ropivacaine for femoral nerve block had a significantly inhibitory effect on local inflammatory response and showed superior postoperative pain control to ropivacaine alone after TKA.
authors.affiliation: Department of Anesthesiology, Honghui Hospital, Xi'an Jiaotong University, Xi'an, China - ljgraceful@126.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Orthopedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, China.
authors.forename: Hanghui
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Anesthesiology, Honghui Hospital, Xi'an Jiaotong University, Xi'an, China.
authors.forename: Buhuai
authors.initials: B
authors.lastname: Dong
authors.affiliation: Department of Orthopedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, China.
authors.forename: Jianbing
authors.initials: J
authors.lastname: Ma
authors.affiliation: Department of Anesthesiology, Honghui Hospital, Xi'an Jiaotong University, Xi'an, China.
authors.forename: Xucai
authors.initials: X
authors.lastname: Wu
mesh_terms: D058647:Adrenergic alpha-2 Receptor Agonists / Q000008:administration & dosage*; D000368:Aged; D000779:Anesthetics, Local / Q000008:administration & dosage*; D019645:Arthroplasty, Replacement, Knee; D020927:Dexmedetomidine / Q000008:administration & dosage*; D004359:Drug Therapy, Combination; D005260:Female; D005267:Femoral Nerve; D006801:Humans; D007249:Inflammation / Q000517:prevention & control*; D008297:Male; D009407:Nerve Block / Q000379:methods*; D011183:Postoperative Complications / Q000517:prevention & control*; D011446:Prospective Studies; D000077212:Ropivacaine / Q000008:administration & dosage*
chemical_list: D058647:Adrenergic alpha-2 Receptor Agonists; D000779:Anesthetics, Local; D020927:Dexmedetomidine; D000077212:Ropivacaine