Regional anesthesia
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The volume of epidural local anesthetic required to achieve a particular dermatomal sensory level varies significantly between patients. Studies have demonstrated random cephalad or caudad migration and direction of the epidural catheter. However, no studies have investigated the relationship between catheter direction and total volume of local anesthetic. ⋯ The authors conclude that epidural catheter direction influences the total dose of local anesthetic required to achieve a specific sensory level in epidural anesthesia.
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Regional anesthesia · Sep 1993
Relationship between time of treatment of acute herpes zoster with sympathetic blockade and prevention of post-herpetic neuralgia: clinical support for a new theory of the mechanism by which sympathetic blockade provides therapeutic benefit.
Since Rosenak's original report more than 50 years ago as to the efficacy of sympathetic blocks in terminating acute herpes zoster, many investigators have reported that a more important benefit of this form of therapy is the prevention of post-herpetic neuralgia. However, most of these reports have indicated that sympathetic blocks are effective in preventing post-herpetic neuralgia only if applied soon after the onset of the acute phase of the disease; in fact, if applied too late, this form of therapy failed to prevent the development of post-herpetic neuralgia. The present study was carried out to determine more precisely the relationship between the time of treatment of acute herpes zoster and the prevention of post-herpetic neuralgia and to attempt to correlate this time with the authors' previously published theory on the mechanism by which sympathetic blocks provide the therapeutic benefit. ⋯ Sympathetic blockade applied within the first 2 months after the onset of acute herpes zoster terminated the acute phase of the disease, probably by restoring intraneural blood flow, thus preventing the death of the large fibers and avoiding the development of post-herpetic neuralgia. If sympathetic blocks were to be carried out after 2 months, the damage to the large fibers would be irreversible, and this therapeutic modality would not be able to prevent the development of post-herpetic neuralgia.
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Regional anesthesia · Sep 1993
Comment Letter Case ReportsTreatment of postdural puncture headache with 'epidural dextran patch'.