title: Ketamine as an adjuvant in lidocaine intravenous regional anesthesia: a randomized, double-blind, systemic control trial.
abstract: OBJECTIVE
  Ketamine delays and minimizes intraoperative tourniquet pain when added to lidocaine-based intravenous regional anesthesia (IVRA). It is unclear if adding ketamine to the IVRA injectate is more efficacious compared with systemic administration. This study compares intraoperative tourniquet pain, postoperative analgesia, and side effects of systemic versus IVRA ketamine during outpatient hand surgery.
  
  
  METHODS
  We conducted a randomized, double-blind, systemic control study of 40 patients undergoing hand surgery using lidocaine IVRA. In group IVRA, 0.1 mg/kg ketamine in 1 mL of normal saline was added to the IVRA lidocaine, and 1 mL of normal saline was administered via a peripheral IV line. In group systemic, 1 mL of normal saline was added to the IVRA syringe, and 0.1 mg/kg ketamine in 1 mL of normal saline was administered via a peripheral intravenous line. Ten minutes after proximal tourniquet inflation, the distal tourniquet was inflated, and the proximal tourniquet deflated. Tourniquet pain was measured every 10 mins. Need for intraoperative opioids was recorded. Recovery room pain scores, analgesic needs, and sedation scores were compared. Patients were contacted 24 hrs after surgery and reported their analgesic consumption, satisfaction scores, and the occurrence of any unpleasant psychologic effects.
  
  
  RESULTS
  Groups IVRA and systemic were comparable in demographic and surgical parameters. There were no differences between groups in intraoperative tourniquet pain scores, intraoperative fentanyl requirements, recovery room pain or sedation scores, postsurgical analgesic needs, or patient satisfaction scores.
  
  
  CONCLUSIONS
  In comparison to systemic administration, there is no selective benefit to adding ketamine to the IVRA injectate.
authors.affiliation: Department of Anesthesiology, University of Vermont College of Medicine, Burlington, VT 05401, USA. christopher.viscomi@vtmednet.org
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Viscomi
authors.forename: Alexander
authors.initials: A
authors.lastname: Friend
authors.forename: Colleen
authors.initials: C
authors.lastname: Parker
authors.forename: Todd
authors.initials: T
authors.lastname: Murphy
authors.forename: Mark
authors.initials: M
authors.lastname: Yarnell
mesh_terms: D000759:Adjuvants, Anesthesia / Q000008:administration & dosage*; D000765:Anesthesia, Conduction / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D004311:Double-Blind Method; D005260:Female; D006225:Hand / Q000601:surgery; D006801:Humans; D007649:Ketamine / Q000008:administration & dosage* / Q000009:adverse effects; D008012:Lidocaine / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000187:drug effects; D010149:Postoperative Pain / Q000188:drug therapy / Q000517:prevention & control*; D011446:Prospective Studies
chemical_list: D000759:Adjuvants, Anesthesia; D000779:Anesthetics, Local; D007649:Ketamine; D008012:Lidocaine