Final answer:
The blanchable erythema over the patient's sacral area is likely due to pressure, which can lead to bedsores. Bedsores result from reduced blood flow and are preventable with regular repositioning to eliminate pressure points.
Step-by-step explanation:
The nurse notes a quarter-sized area of blanchable erythema over the patient's sacral area. The finding of blanchable erythema is likely due to pressure on the skin. When skin and its underlying tissue are subjected to constant, unrelieved pressure, it can result in a bedsore, also known as a decubitus ulcer. These sores occur due to reduced blood flow to the area because of the pressure, which can lead to tissue necrosis if left untreated. Bedsores are commonly found in patients who are immobile for long periods, and they are preventable by eliminating pressure points and repositioning the patient regularly.