This is one of the great medical myths. I blame my profession for it, along with the marketing departments of the vendors. Rant follows:
Sterile is sterile. Loss of sterility is event related, not time related. To render a sterile product non-sterile, you gotta penetrate the packaging and put some microorganisms on it. Sterile items remain sterile as long as the packaging is intact. Intact means not perforated and dry. During WWII, the OR at columbia-presbyterian hospital was short of cotton sterile wraps, so the wrapped some of their sets in newspaper and autoclaved them. These sets found their way to the back of the closet, and were rediscovered in the '60's. Opened and tested, the sets were proven to still be sterile, Presumably because the wrappers were intact, not because the microbes died of old age. Sterile products become unsterile before the expiration date if contaminated by breach of packaging, and stay sterile long after expiration if the package is intact. Expiration dates are applied to such by folks who don't look at the science.

"Wound packing" is an interesting term. IME, it is applied to treatment of a draining wound to maintain an opening to permit drainage to continue. If a boil/abscess is lanced, the wound will be packed with iodoform or plain gauze ribbon(or a latex drain), so that the wound does not close and trap infected material or blood inside, causing another abscess or hematoma. Stopping the bleeding, or hemostatsis, involves bulky dressings and pressure-Kerlix sponges, abdominal pads, tampons (generic term for big rolls of gauze), surgical sponges, wrapped up in ace bandages, or with manual pressure.

There is another approach to hemostatsis. Many of us carry locking forceps as a matter of course.One of the original purposes of this device was hemostasis-some folks call them hemostats. The procedure is, you look in the wound, identify a big artery or vein, and then clamp it off. Easier if you are a surgeon, and have just cut the vessel, and are working in an OR with bright lights, sterile surroundings, and OR staff to hand you the clamp. Harder if you are upside down in a ditch, in the dark, in the snow, all by yourself. Which is why paramedics are paid better than surgeons...you say they're not paid better than surgeons?...something is terribly wrong...