Medical equipment and medications are all excempt from baggage limits, etc. So you can bring them as carry ons, incuding your vest if you have one.
I put all DS's meds in a clear make up bag with labels facing out -- make sure all have prescription labels on them. I have an old doctor's letter indicating DS has cystic fibrosis, but after a trip to mexico last February and being taken aside at our local airport because we have a "breathing device", think we need it updated. Scared the heck out of me. Thought they weren't going to let us travel. Found out later from Emily (when hers got taken apart and security cleared the airport), there'd been a scare a few years back with someone putting an explosive device in a nebulizer and trying to get thru security.
You should also declare to them prior to going thru security that you have medications and medical equipment. Regs have changed recently regarding carryons, toiletries -- size limitation and need to be in a plastic baggy. My MIL got stopped last week because she didn't realize she had a bottle of nailpolish in her purse that wasn't in a baggy. She didn't even realize it was IN her purse and they gave her a tough time.