Final answer:
The nurse cuts the black foam to fit gently into the wound bed without overlapping onto intact periwound skin to prevent erythema.
Step-by-step explanation:
The nurse cuts the black foam to fit gently into the wound bed without overlapping onto intact periwound skin in order to prevent erythema to the intact skin. By avoiding contact with intact skin, the nurse minimizes the risk of irritation or inflammation, which reduces the chance of developing redness, swelling, and pain in the surrounding area. This is important for maintaining the overall healing process and preventing further complications.