A patient who has just begun taking an angiotensin-converting enzyme (ACE) inhibitor calls the nurse and reports feeling very dizzy when standing up, and asks if the medication should be discontinued. What is the nurse's best response?

Choice A reason: Hyperplasia and deformation of bronchial cartilage are not the causes of airway obstruction in COPD type B. Bronchial cartilage is the rigid structure that supports the bronchi, the large airways that branch from the trachea. Hyperplasia is an increase in the number of cells, and deformation is a change in the shape or structure of the cells. These processes can affect the bronchial cartilage, but they do not directly obstruct the airway.

Choice B reason: Loss of alveolar elastin is not the cause of airway obstruction in COPD type B. Alveolar elastin is the elastic fiber that allows the alveoli, the tiny air sacs at the end of the bronchioles, to expand and recoil during breathing. Loss of alveolar elastin is a characteristic of COPD type A (emphysema), which causes the alveoli to lose their shape and collapse. This reduces the surface area for gas exchange, but it does not obstruct the airway.

Choice C reason: Pulmonary edema is not the cause of airway obstruction in COPD type B. Pulmonary edema is the accumulation of fluid in the lungs, usually due to heart failure or lung injury. It causes shortness of breath, coughing, and crackles in the lungs. It can impair gas exchange and oxygenation, but it does not obstruct the airway.

Choice D reason: Thick mucus, fibrosis, and smooth muscle hypertrophy are the causes of airway obstruction in COPD type B. Thick mucus is the result of chronic inflammation and infection of the bronchi, which stimulates the mucus glands to produce more and thicker mucus. Fibrosis is the formation of scar tissue in the bronchial walls, which narrows the airway and reduces its elasticity. Smooth muscle hypertrophy is the enlargement of the smooth muscle cells that surround the bronchi, which increases the airway resistance and causes bronchospasm. These processes combine to obstruct the airway and cause chronic cough, wheezing, and dyspnea.

Choice A reason: An increase in antithrombotic substances is not a cause of atherosclerosis. Antithrombotic substances are agents that prevent or reduce the formation of blood clots. They can be used to treat or prevent atherosclerosis, not cause it.

Choice B reason: Congenital heart disease is not a cause of atherosclerosis. Congenital heart disease is a condition that is present at birth and affects the structure or function of the heart. It can be caused by genetic or environmental factors, not by atherosclerosis.

Choice C reason: Endothelial injury and inflammation are causes of atherosclerosis. Endothelial injury is the damage to the inner lining of the blood vessels, which can be caused by various factors such as high blood pressure, high cholesterol, smoking, or diabetes. Inflammation is the body's response to the injury, which involves the activation of immune cells and the release of cytokines and growth factors. These processes lead to the formation of plaque, which is composed of cholesterol, fatty substances, calcium, and other materials.

Choice D reason: High serum potassium levels are not a cause of atherosclerosis. High serum potassium levels are a condition that affects the balance of electrolytes in the blood. It can be caused by kidney disease, medication side effects, or excessive intake of potassium-rich foods. It can affect the heart rhythm and function, but it does not cause atherosclerosis.