Changes in Skin Conductance Measurement as an Endpoint Monitor for Sympathetic Blocks

"A lumbar sympathetic block is an injection in the middle of the lower back, toward the left or right side. The lumbar sympathetic nerves are a small bundle of nerves that carries sympathetic nerve signals from the lower extremities. In some instances, certain injuries to the lower extremities can cause a burning, unusual pain called complex regional pain syndrome or reflex sympathetic dystrophy. Injecting a small amount of local anesthetic on the lumbar sympathetic nerves can identify whether or not this pain is carried by the sympathetic nervous system."

The real-time changes in skin conductance indices can be monitored at the skin level, by use of non-invasive electrodes attached to the skin (similar to EKG electrodes) connected to the skin conductance algesimeter. A computer program analyzes the data and produces a real-time graphic and numeric data demonstrating the skin conductance response. The initiation of successful sympathetic blockade can cause rapid cessation of the skin sympathetic activity that leads to a decrease in skin conductance within seconds.