Or: steril barrierelommepose/ lommepose der udgør en steril barriere. In other contexts "posetaske", "poselomme", "rumlig pose", "(stof)poseetui" etc. It also has many names in anatomy - "sæk", "pose", "pung", "udbuling" etc., but that is not relevant right here.

Making a search for pouch on Google Images, you will see the many and wide-ranging possibilities; we don't have a similar all-encompassing term in Danish, but it is basically a spacious bag or pocket (sometimes handbag) meant to hold something.