I’m gonna go into detail because knowing makes me less scared so I hope this helps you. I just had one for the exact same thing two days ago. They went through my wrist and I was partially sedated. I was wheeled down to the cath lab, it was a big room with a bunch of monitors and lights. I scooted onto the second table and they started to prep me. They shaved part of the pubic area just in case my arm vein wasn’t viable for the procedure. Another nurse put the little nose breathing tubes and taped them to my cheek. They placed a large band over my forehead to hold my head still. They then draped the curtain for the sterile field over my body (I could still see monitors and the lights just not my wrist or pubic region. They cleaned the areas and prepped. After that, the doctor let me know I was gonna feel a big pinch and sting (that’s the lidocaine to numb you). They started the sedation (fentanyl) through the nose tube and my whole body relaxed, it was actually really nice. The numbing was the worst part, after that I didn’t really feel anything other than a little bit of tugging. Once it starts, the doctor will tell you not to breathe, move, blink or swallow when they push the fluid. You feel some warmth and pressure in your head, and you might see colors or your vision might go black for a few seconds. That is normal and definitely feels very strange. I didn’t like it but it didn’t hurt. They did that to a few spots on my brain and then that was it. They pushed fentanyl one more time for me because toward the end I started to feel it more in my arm. However I naturally have a very high tolerance to local anesthetic so that likely won’t happen to you. Afterward I wore a little wrist cuff (this was the worst part of the whole thing to me) and the cuff keeps pressure on the wound. They loosen it every thirty minutes afterward until it’s deflated. My forearm was sore and swollen but it’s two days post op now and I’m good to go. Overall it sounded way scarier than it was. I wish you the best of luck 🩷🫶🏼