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Does the sympathetic block outlast sensory block: a thermographic evaluation
William E Strong1, Janna Blanchard, S Ramamurthy
1Anesthesia and Operative Service, Brooke Army Medical Center, Fort Sam Houston, TX 78234-6200 U.S.A. Department of Anesthesiology, University of Texas Health Science Center, San Antonio, TXU.S.A.
Pain
|August 1, 1991
Summary
Sympathetic and sensory epidural block durations were compared in L2 and L5 dermatomes. Sympathetic block duration was longer than sensory block at L5, but not L2, indicating unpredictable durations in epidural studies.
Area of Science:
- Anesthesiology
- Pain Management
- Neurology
Background:
- Epidural anesthesia is widely used for surgical procedures and pain management.
- Understanding the differential block characteristics, specifically the duration of sympathetic versus sensory blockade, is crucial for optimizing anesthetic techniques and patient outcomes.
- Previous studies have yielded varied results regarding the comparative duration of sympathetic and sensory blockade.
Purpose of the Study:
- To evaluate and compare the duration of sympathetic and sensory blockade in the L2 and L5 dermatome distributions following epidural administration of 2% lidocaine with epinephrine.
- To determine if the duration of sympathetic block can be reliably predicted by the duration of sensory block.
Main Methods:
- A prospective study involving twenty patients undergoing epidural block with 2% lidocaine and epinephrine.
- Thermography was utilized to assess sympathetic blockade, while pinprick sensation was used to evaluate sensory blockade.
- Onset and duration of both sympathetic and sensory blocks were recorded and statistically analyzed for L2 and L5 dermatomes.
Main Results:
- No statistically significant difference was observed in the duration of sensory and sympathetic block at the L2 dermatome.
- Sympathetic blockade demonstrated a significantly longer duration compared to sensory blockade in the L5 dermatome.
- Individual patient variability in the duration of sympathetic blockade relative to sensory blockade was noted.
Conclusions:
- The duration of sympathetic epidural block can be either longer or shorter than sensory epidural block, depending on the specific dermatome (L2 vs. L5).
- Predicting the duration of sympathetic blockade based solely on the duration of sensory blockade is not reliable.
- These findings have significant implications for the interpretation of differential epidural block studies and the clinical management of patients receiving epidural anesthesia.