A 45-year-old male client with leg ulcers and arterial insufficiency is admitted to the hospital. The nurse understands that leg ulcers of this nature are usually caused by:
A. Decreased arterial blood flow secondary to vasoconstriction.
B. Decreased arterial blood flow leading to hyperemia.
C. Atherosclerotic obstruction of the arteries.
D. Trauma to the lower extremities.
Correct Answer: A. Decreased arterial blood flow secondary to vasoconstriction.
Decreased arterial flow is a result of vasospasm. The etiology is unknown. It is more problematic in colder climates or when the person is under stress. A 50% decrease in vessel diameter corresponds to a 75% loss of cross-sectional area which is usually considered flow limiting. As the narrowing progresses or completely obstructs the artery, blood flow shifts to smaller arteries which parallel the diseased artery. Although this collateral flow preserves distal perfusion, the network of smaller vessels never carries as much blood flow as the main artery.
Option B: Hyperemia occurs when the vasospasm is relieved. Hyperemia occurs when excess blood builds up inside the vascular system, which is the system of blood vessels in the body. When excess blood occurs outside the vascular system, due to a broken blood vessel or injury, this is known as hemorrhage. The buildup of blood may present as a red, warm, painful, swollen area.
Option C: Atherosclerosis (sometimes called “hardening” or “clogging” of the arteries) is the buildup of cholesterol, fatty cells and inflammatory deposits (called plaque) on the inner walls of the arteries that restrict blood flow to the heart. Atherosclerosis can affect the arteries in the heart, legs, brain, kidneys and other organs.
Option D: When the arterial vessel is transected, vascular spasm coupled with low systemic blood pressure appears to promote clotting at the site of injury and to preserve vital organ perfusion better than is the case with ongoing uncontrolled hemorrhage. This partially explains the prehospital finding that in the subset of penetrating trauma, limited or no fluid resuscitation until arrival at the hospital may improve patient survival and outcome.
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