title: Intravenous regional anesthesia with clonidine in the management of complex regional pain syndrome of the knee.
abstract: OBJECTIVE
  To evaluate the safety and efficacy of administering intravenous regional anesthesia (IVRA) with clonidine in the management of complex regional pain syndrome (CRPS) of the knee.
  
  
  METHODS
  Prospective, non-blinded study.
  
  
  METHODS
  University-affiliated pain management center.
  
  
  METHODS
  7 patients with the diagnosis of CRPS of the knee. The diagnosis of CRPS was made if a) patients had at least four of these symptoms: allodynia, hyperesthesia, edema, vasomotor changes, pain with a burning quality, sudomotor changes, joint stiffness, or temperature differences between extremities; b) patients had significant pain relief (>75%) after a lumbar sympathetic block.
  
  
  METHODS
  Each patient received IVRA with a solution containing clonidine 1 microg/kg in a total volume of 50 mL 0.5% lidocaine. IVRA clonidine (IVRA-C) was performed on each patient up to six times (maximum of once a week for six weeks). MEASUREMETNS: Pain was assessed using a verbal pain scale (VPS) between 0 and 10 before each IVRA-C treatment. Duration of pain relief was defined as the time during which the patients experienced no pain (VPS = 0). Continuous electrocardiogram (ECG) and pulse oximetry (SpO2) were monitored and blood pressure was recorded every 5 minutes for the first 60 minutes after tourniquet deflation.
  
  
  RESULTS
  Five patients received complete pain relief with 4 to 6 IVRA-C blocks. The two remaining patients reached a therapeutic plateau from IVRA-C, but had persistent anatomic lesions contributing to the recurrence of their CRPS. No patient experienced hypotension (mean arterial pressure < or = 20% baseline), hypoxemia (SpO2 < or = 90%), bradycardia (heart rate < or =H 60 beats/min), or excessive sedation.
  
  
  CONCLUSIONS
  IVRA-C is a useful treatment modality in the management of CRPS of the knee. Clonidine doses of 1 microg/kg appear to be well tolerated without significant side effects.
authors.affiliation: Department of Anesthesiology, Baystate Medical Center, Springfield, MA 01199, USA. scott.reuben@bhs.org
authors.forename: Scott S
authors.initials: SS
authors.lastname: Reuben
authors.forename: Joseph
authors.initials: J
authors.lastname: Sklar
mesh_terms: D000328:Adult; D000700:Analgesics / Q000008:administration & dosage*; D000765:Anesthesia, Conduction; D003000:Clonidine / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007717:Knee; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D011446:Prospective Studies; D012019:Reflex Sympathetic Dystrophy / Q000628:therapy*
chemical_list: D000700:Analgesics; D003000:Clonidine