you can use any pattern you want.
I just did normal binding you can finish it by machine as long as there is not a large lip on the back where it could get caught on an IV line or port or anything!
I use Warm and Natural in everything I do even these. The directions I have says use only 1/8 - 1/4 inch low loft batting. I don't see why you couldn't use W&N.
I know from my many stays in the hospital they are not always the warmest places to be. While I was in the hospital for several weeks I used a hair blowdryer to keep warm! lol