What are possible complications of IV regional sympathetic blocks for pain management?

Updated: Jun 19, 2018
  • Author: Anthony H Wheeler, MD; Chief Editor: Meda Raghavendra (Raghu), MD  more...
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Problems with the use of guanethidine include the initial effect of the drug, which causes an increase in NE and consequent cutaneous vasoconstriction, piloerection, and burning dysesthesia. Some of the guanethidine that escapes occlusion of the circulation by tourniquet may produce side effects including tachycardia and dizziness, as well as other signs and symptoms of sympathetic blockade. Cardiac, blood pressure, and other vital signs should be monitored closely, and appropriate resuscitative measures and equipment should be available at the bedside.

Patient anxiety may increase with the transient rise in NE levels secondary to the guanethidine effect. Prior to the procedure, 100 mg of thiopental, 5-10 mg of IV diazepam, or 3-5 mg of IV morphine should be considered to minimize the pain and discomfort inherent to the procedure. Pain resolution associated with regional infusion of guanethidine can be considered sympathetically mediated from a diagnostic standpoint. Repeating this procedure on an outpatient basis may be necessary; patients with severe CRPS may require re-treatment every 3 days, whereas patients with milder CRPS may require therapeutic intervention only at 3-week intervals. Usually, treatment is limited to 2-3 sessions.

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