Certified Rehabilitation Registered Nurse (CRRN) Practice Exam

What intrinsic factor affects tissue tolerance and is responsible for pressure ulcer development?

1. Low arteriolar pressure

2. High body mass index

3. Chronic inflammation

4. Age-related skin elasticity

The correct answer is: Low arteriolar pressure

The correct answer focuses on the role of low arteriolar pressure in affecting tissue tolerance, thereby contributing to the development of pressure ulcers. Pressure ulcers occur when there is prolonged pressure on the skin, which can impede blood flow to the tissues. When arteriolar pressure is low, the blood supply to a particular area of the body—especially over bony prominences—can become insufficient to meet the metabolic needs of the tissue. This lack of adequate blood flow means that nutrients and oxygen are not delivered efficiently, and waste products are not removed, ultimately leading to tissue ischemia and necrosis. Other options, such as high body mass index, chronic inflammation, and age-related skin elasticity, can influence the risk of developing pressure ulcers but do not directly assess tissue tolerance in the same manner that arteriolar pressure does. High body mass index may increase pressure on the skin but does not directly affect the local blood supply. Chronic inflammation could contribute to skin integrity issues, while age-related skin elasticity impacts how the skin responds to pressure but is not as directly connected to tissue perfusion as arteriolar pressure.