A client reports weakness, dizziness, nausea and vomiting that has lasted for three days. The nurse's assessment reveals dry tongue and oral mucosa, and dark concentrated urine. Which additional assessment would best evaluate the client's fluid status?

Choice A reason: The pain you have is because your heart valves are damaged is not the most appropriate response. This statement may apply to a client with valvular heart disease, but not necessarily to a client with coronary artery disease. The nurse should explain that coronary artery disease is a condition that affects the blood vessels that supply the heart, not the heart valves.

Choice B reason: Your heart muscle is weak and is not pumping forcefully is not the most appropriate response. This statement may apply to a client with heart failure, but not necessarily to a client with coronary artery disease. The nurse should explain that coronary artery disease is a condition that reduces the blood flow to the heart, not the heart's contractility.

Choice C reason: The pain is caused by decreased oxygen to the heart muscle is the most appropriate response. This statement accurately describes the cause of angina, which is the chest pain that occurs when the heart does not receive enough oxygen due to narrowed or blocked coronary arteries. The nurse should also inform the client about the factors that can trigger or relieve angina, such as physical exertion, emotional stress, cold weather, or nitroglycerin.

Choice D reason: The layers of your heart are weak and thin is not the most appropriate response. This statement may apply to a client with cardiomyopathy, but not necessarily to a client with coronary artery disease. The nurse should explain that coronary artery disease is a condition that affects the blood vessels that supply the heart, not the heart's structure.

Choice A reason: This is not the best answer. Respiratory rate and depth can indicate the client's oxygenation and ventilation, but not necessarily their fluid status. The client may have normal or increased respiratory rate and depth due to dehydration, acidosis, or anxiety, but this does not reflect their fluid volume or distribution. The nurse should monitor the client's respiratory rate and depth, but also assess other parameters of fluid status.

Choice B reason: This is not the best answer. Rectal temperature can indicate the client's core body temperature, but not necessarily their fluid status. The client may have normal or elevated rectal temperature due to infection, inflammation, or dehydration, but this does not reflect their fluid volume or distribution. The nurse should monitor the client's rectal temperature, but also assess other parameters of fluid status.

Choice C reason: This is the best answer. Blood pressure lying, sitting and standing can indicate the client's fluid status and vascular tone. The client may have low blood pressure due to fluid loss, hypovolemia, or vasodilation, and this can cause orthostatic hypotension, which is a drop in blood pressure when changing positions. The nurse should measure the client's blood pressure in different positions and observe for signs of orthostatic hypotension, such as dizziness, fainting, or blurred vision.

Choice D reason: This is not the best answer. Pulse oximetry reading at rest can indicate the client's oxygen saturation, but not necessarily their fluid status. The client may have normal or decreased pulse oximetry reading due to hypoxia, anemia, or poor peripheral perfusion, but this does not reflect their fluid volume or distribution. The nurse should monitor the client's pulse oximetry reading, but also assess other parameters of fluid status.