title: Dexmedetomidine added to ropivacaine extends the duration of interscalene brachial plexus blocks for elective shoulder surgery when compared with ropivacaine alone: a single-center, prospective, triple-blind, randomized controlled trial.
abstract: OBJECTIVE
  Research suggests that the addition of dexmedetomidine to local anesthetics can prolong peripheral nerve blocks; however, clinical safety data are limited, and interscalene blocks have not been studied. The present study was designed to test the hypothesis that dexmedetomidine added to ropivacaine would safely enhance the duration of analgesia without adverse effects when compared with ropivacaine alone.
  
  
  METHODS
  We conducted a single-center, prospective, randomized, triple-blind, controlled trial of 62 patients undergoing elective shoulder surgery under general anesthesia with an interscalene block. Patients underwent ultrasound-guided interscalene blocks using either 12 mL of 0.5% ropivacaine or 0.5% ropivacaine plus 150-µg dexmedetomidine. The primary outcomes were self-reported duration of the nerve block and safety assessment (adverse effects and neurological sequelae). Data were analyzed in a blinded fashion.
  
  
  RESULTS
  The median duration of the nerve block was 18 hours (95% confidence interval, 18-20) in the dexmedetomidine group and 14 hours (95% confidence interval, 14-16) in the ropivacaine group (P = 0.0001). Dexmedetomidine also lowered pain scores for the first 14 hours postoperatively and significantly hastened the time to sensory (P = 0.04) and motor (P = 0.002) block onset. Dexmedetomidine lowered heart rate but blood pressures were stable. Plasma levels of ropivacaine were not different between groups, and plasma dexmedetomidine levels were relatively low. There were no adverse events or neurological sequelae.
  
  
  CONCLUSIONS
  Dexmedetomidine added to ropivacaine for interscalene blocks increased the duration of the nerve block and improved postoperative pain. These additional efficacy and safety data should encourage further study of peripheral perineural dexmedetomidine in humans.
authors: From the *Department of Anesthesiology, Perioperative Medicine, and Critical Care Medicine, Paracelsus Medical University, Salzburg, Austria; †Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, MI; ‡Department of Laboratory Medicine, Paracelsus Medical University, Salzburg, Austria; and §Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI.
authors: Gerhard
authors: G
authors: Fritsch
authors: Thomas
authors: T
authors: Danninger
authors: Karl
authors: K
authors: Allerberger
authors: Alexander
authors: A
authors: Tsodikov
authors: Thomas K
authors: TK
authors: Felder
authors: Monika
authors: M
authors: Kapeller
authors: Peter
authors: P
authors: Gerner
authors: Chad M
authors: CM
authors: Brummett
mesh_terms: D000328:Adult; D000577:Amides / Q000008:administration & dosage*; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage; D000779:Anesthetics, Local / Q000008:administration & dosage; D001917:Brachial Plexus / Q000187:drug effects / Q000601:surgery*; D020927:Dexmedetomidine / Q000008:administration & dosage*; D004359:Drug Therapy, Combination; D017558:Elective Surgical Procedures / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D010149:Postoperative Pain / Q000175:diagnosis / Q000517:prevention & control*; D011446:Prospective Studies; D000077212:Ropivacaine; D012782:Shoulder / Q000601:surgery
chemical_list: D000577:Amides; D018712:Analgesics, Non-Narcotic; D000779:Anesthetics, Local; D020927:Dexmedetomidine; D000077212:Ropivacaine