The stellate ganglion and nearby cervical sympathetic ganglia will be blocked with 10 mL 0.5 percent bupivacaine under ultrasound guidance.

Reciprocal unilateral stellate ganglion blocks, separated by at least 16 hours, will be given once per week for three weeks (for a total of 6 blocks).

This study is not intended to be reported to FDA as a well-controlled study in support of a new indication for bupivacaine or to support any other significant change in the labeling for the drug.

The primary objective of the clinical trial is to evaluate whether stellate ganglion block treatment improves the subjective rating of symptoms (severity and frequency) and the amount of limitations to activities. We will measure the change from baseline scores at two weeks for the DePaul Symptom Questionnaire to measure the frequency and severity of symptoms (on a scale of 0 to 4 in which a higher score indicates more frequent or more severe) and the Rand Short Form-36-Physical Fatigue subscale (SF-36PF) to measure the amount of limitations due to symptoms (on a scale of 1-3 in which a higher score indicates less limitation).

The primary objective of the clinical trial is to evaluate whether stellate ganglion block treatment improves the subjective rating of symptoms (severity and frequency) and the amount of limitations to activities. We will measure the change from baseline scores at two months for the DePaul Symptom Questionnaire to measure the frequency and severity of symptoms (on a scale of 0 to 4 in which a higher score indicates more frequent or more severe) and the Rand Short Form-36-Physical Fatigue subscale (SF-36PF) to measure the amount of limitations due to symptoms (on a scale of 1-3 in which a higher score indicates less limitation).

The primary objective of the clinical trial is to evaluate whether stellate ganglion block treatment reduces "brain fog" as measured by computerized neurocognitive tests for attention, executive function, and memory. Scores are standardized and scaled to adjust for age and the device on which tests are taken. Scores range from 0 to 200, in which the average score (corresponding to the 50th percentile) is set to 100, and higher scores indicate better cognitive function. Scores are obtained for attention, executive function, and memory. Scores at baseline will be compared to scores at two weeks post-treatment.

The 10-minute National Aeronautics and Space Administration (NASA) lean test will be used to measure hemodynamic changes during orthostatic challenge (lying down vs. standing up). The study will measure change from baseline at 2 weeks post-treatment.

Concentration of free cortisol in saliva upon awakening will be measured in micrograms per deciliter (ug/dL) using Enzyme-Linked Immunosorbent Assay (ELISA), at baseline and two weeks after treatment. ME/CFS patients have abnormally low levels of cortisol in general and upon awakening. An increased concentration within the normal range (from 0.007 ug/dL to 0.115 ug/dL) indicates a better outcome.