Have you ever been inside an OR during surgery or seen a sponge? I spent two months watching my boss perform open heart surgery. Let me tell you, there is a great deal of blood. The sponges are inside the thoracic cavity during the procedures, and there is so much blood that they almost appear to be part of the tissue. The ones I saw also weren't that big, and they look nothing like the sponges we use in the shower. Certainly this type of incident should not happen, and the OR staff works hard to keep track of equipment; however, don't trivialize how difficult that can be under the conditions of a surgical procedure. It is a mess in there.