Measurement of the Skin Sympathetic Nerve Activity During Stellate, Thoracic, and Lumbar Sympathetic Ganglia Block

Seoul National University Hospital32 enrolled

Overview

Sympathetic nerve activity can be measured transcutaneously in awake patients by computer-based filtering of raw signal obtained via skin leads attached on the chest and the right arm. Electrocardiogram can be removed by applying a high-pass filter setting of 150 Hz. Electromyogram can be filtered by applying a high-pass filter setting of 500 Hz or a band-pass filter setting of 500-1000 Hz. Currently, the therapeutic effect of stellate, thoracic, and lumbar sympathetic ganglia block (SGB, TSGB, and LSGB, respectively) in patients with chronic pain is generally evaluated by using thermogram/thermography (change in temperature of the upper or lower extremeties) or questionnaire-based scoring. However, it is not known whether the skin sympathetic nerve activity (SKNA) can be measured in patients undergoing SGB/TSGB/LSGB and used as an alternative tool for assessing the therapeutic effect of SGB/TSGB/LSGB. Therefore, we planned this pilot study to observe whether the SKNA can be obtained in patients undergoing SGB/TSGB/LSGB and whether it is well correlated to thermogram or questionnaire-based scoring. If the SKNA is observed and decreases after SGB/TSGB/LSGB, it will be presented in milivolt (uV) and compared to that of pre-block values.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Chronic Pain Requiring Stellate, Thoracic, and Lumbar Sympathetic Ganglia Blockade

Eligibility

Sex: ALL

Medical Language ↔ Plain English

Inclusion Criteria: * Outpatient patients undergoing stellate, thoracic, and lumbar sympathetic block for chronic pain disease Exclusion Criteria: * patients denial * peripheral vascular disease in the head and the upper extremities. * prior thoracic sympathectomy/sympathicotomy * prior resection or ablation (chemically or mechanically) of stellate, thoracic, and lumbar sympathetic * coagulapathy * infectious disease * allergy to local anesthetics

Outcomes

Primary Outcomes

The skin sympathetic nerve activity presented as uV obtained via skin leads.

A few studies reported that skin sympathetic nerve activity (SKNA) signal could be potentially observed by applying a high-pass filter of 500 Hz or a band-pass filter of 500\~1000 Hz to electric signal from skin leads attached on the skin of the chest in awake volunteers. However, it is not known if it would be also possible to observe the SKNA signal in patients undergoing stellate, thoracic, and lumbar sympathetic block. Also, there is no established, objective tool for quantitative or qualitative assessment of the effect of stellate, thoracic, and lumbar sympathetic block.

Time frame: From the beginning of stellate, thoracic, or lumbar sympathetic block procedure and the next outpatient visiting 4 weeks (an average) after the procedure.