Intravenous regional anesthesia with clonidine in the management of complex regional pain syndrome of the knee.
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.
Reuben
Scott S
SS
Department of Anesthesiology, Baystate Medical Center, Springfield, MA 01199, USA. scott.reuben@bhs.org
Sklar
Joseph
J
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*
D000700:Analgesics; D003000:Clonidine