Being a scuba diver, I have one piece of advice if you have no experience in that area...

In the chamber, you will be "taken down" to 2 or 3 atmosphere's of pressure. That's 60 to 90 feet. About every 10 feet, you'd going to have to equalize your ears. Have you ever been to the bottom of the pool and felt that ear pain? That's a pressure equalization problem. It's easy to equalize, but some people have more trouble than others. Some people just have to move their jaws around, and that's all it takes to get their ears to "pop" and equalize. I'm not so lucky. I have to plug my nose and gently try to blow out my nose. I assume the nurse in the chamber would tell you that trick, but I thought I'd mention it just in case.

I was in a chamber a few times for a minor diving incident. It's not bad at all. Just take a book to read or something to keep you occupied. You'll actually come out feeling pretty energized.