Final answer:
Immobility is the factor that contributes to the formation of pressure ulcers by reducing blood flow to certain areas of the body, increasing tissue demand for oxygen, and potentially leading to bedsores.
Step-by-step explanation:
The factor which contributes to the formation of pressure ulcers in a client and increases the cells' need for oxygen is immobility. When individuals are unable to move sufficiently, constant, unrelieved pressure is placed on certain parts of the body, typically over bony prominences. This pressure impedes blood flow to the tissue, resulting in a lack of oxygen and nutrients that can lead to tissue necrosis and the development of bedsores, or decubitis ulcers. Preventative measures in healthcare settings often include repositioning patients regularly to alleviate this pressure.