if you DIY...you can reduce the volume and waterproof ..use a vacuum food sealer...make small "v" cuts at the corners to help open the pack...
That's exactly how I do it. Vacuum sealing is very handy for many items. I like to seal 1st aid stuff but also survival gear. Since I rely on a firesteel quite a bit for fire making I like to keep some really good reliable tinder vacuum sealed in case things are very wet. My packs vary; some contain a bit of fatwood, some contain Tinder-Qwik. PJ cotton balls are a favorite tinder of mine. I've also sealed some Weber cubes, too.
Sealing dressings and bandages is a good idea, but just make sure to seal a little zip lock baggie for the extras. Once you break the seal you need something to carry the stuff that you didn't use.