It is used to reduce sympathetic nervous system activity:
‘SGB has been shown to reduce hyperarousal and stress-related symptoms, possibly through vagal modulation of central autonomic circuits’ (Central effects of stellate ganglion block mediated by the vagus nerve? An alternate hypothesis for treating PTSD - Johns Hopkins University )
Obviously we’re not doctors here, so I guess if it was something you wanted to try, this would be best discussed with a doctor. The vagus nerve is often compressed at the same time as the IJV as they are next to each other…