Hi Linda, welcome to the board, I'm glad your doc caught the rsd early! I've had the stellate ganglion blocks, with sedation, and they are nothing to fret about. A bunch of people here have had them w/o sedation, so it just depends on your doc, but if you want sedation, let your doc know beforehand. It almost takes longer to start the IV than it does to do the block. Make sure that no-one ever puts an IV or draws blood from your rsd arm. That's a no-no.
When I had my blocks, after the IV was started and the doc got there, the nurse gave me a short acting sedative. My doc pushed on my throat, which to me was the most uncomfortable part because they have to push on your trachea. Some docs will numb the area before inserting the longer needle needed for the block, but my doc only did that for the first of my 10 blocks. Anyway, then he'll insert the needle in your neck and push the meds. You'll feel pressure as the meds go in, and hopefully your arm will start to feel a warmish sensation, the temp of your hand will increase (they should stick a temp strip on it), and your pain will go away.
Afterwards, you should get what they call 'droopy eye' if the block is successful, and your neck may be sore for a few days.
One thing no-one told me about was that occassionally, the medicine can spread to your throat. It happened to me with my first block, and since no-one had told me about it beforehand, it scared me when I suddenly discovered that I was having trouble talking and swallowing. I wanted to let you know so if it does happen to you, you'll know it's just a temporary complication that sometimes happens, and it'll wear off and you'll be okay. Do let the nurse, and your doc know of it does happen though.
How long the pain stays gone varies greatly from patient to patient, but the idea is to get them to last longer with each block. If the pain comes back, call you're doc and get another block. My doc did a test block to see if it would help, and then we scheduled a series of 5 blocks... 2 per week. Pre-schedule your blocks if you can, that way, you won't have to wait weeks for another if your doc has a full schedule.
I hope this helps you relax some about the blocks. They really only take a couple of minutes to do and they aren't painful. You may or may not feel a little discomfort from the pressure I mentioned, but that should be it. I'll be keeping my fingers crossed that your block is extremely successful, and please keep us posted with how your block went.
Take care, and have as pain-free a night as possible.
Cathy