A nurse is monitoring a client who is receiving a unit of packed red blood cells (RBCs) following surgery. Which of the following assessments is an indication that the client might be experiencing circulatory overload?

Choice A reason: A headache is not likely due to the anxiety about the chest pain, as anxiety usually causes other symptoms, such as palpitations, sweating, or trembling. A headache is more likely related to the vasodilating action of nitroglycerin, which causes increased blood flow to the brain.

Choice B reason: A headache does not indicate tolerance to the medication, as tolerance usually manifests as a reduced effect of the medication on relieving chest pain. A headache is more likely a sign of the medication's potency, as it indicates that the nitroglycerin is reaching the systemic circulation.

Choice C reason: A headache is an expected adverse effect of the medication, as nitroglycerin causes vasodilation of the cerebral vessels, which can result in increased intracranial pressure and pain. A headache is usually mild and transient, and can be relieved by taking analgesics, such as acetaminophen.

Choice D reason: A headache is not an indication of an allergy to the medication, as an allergic reaction usually causes other symptoms, such as rash, itching, swelling, or difficulty breathing. A headache is more likely a pharmacological effect of the medication, rather than an immunological response.

Choice A reason: "Place one tablet under your tongue every 5 minutes for 30 minutes to relieve chest pain." is not the correct statement. This is an incorrect and potentially dangerous instruction, as it can cause overdose and severe hypotension. The nurse should instruct the client to place one tablet under the tongue at the first sign of chest pain, and repeat every 5 minutes for up to three doses, if needed. The client should call 911 if the pain is not relieved after the first dose.

Choice B reason: "Nitroglycerin decreases chest pain by dissolving blood clots that are occluding the arteries." is not the correct statement. This is a false and misleading explanation of how nitroglycerin works. Nitroglycerin does not dissolve blood clots, nor does it affect the occlusion of the arteries. Nitroglycerin is a vasodilator that relaxes the smooth muscle of the blood vessels, especially the veins. This reduces the preload and the oxygen demand of the heart, and relieves the chest pain caused by ischemia.

Choice C reason: "You can store the bottle of tablets in your bathroom medicine cabinet." is not the correct statement. This is an inappropriate and unsafe storage recommendation, as it can affect the potency and effectiveness of the medication. The nurse should instruct the client to store the bottle of tablets in a cool, dry, and dark place, away from heat, moisture, and light. The client should also keep the bottle tightly closed and replace it every 6 months, or as directed by the provider.

Choice D reason: "Nitroglycerin dilates cardiac blood vessels to deliver more oxygen to the heart." is the correct statement. This is a simple and accurate description of how nitroglycerin helps to relieve anginal pain. Nitroglycerin dilates the coronary arteries, which supply blood and oxygen to the heart muscle. This improves the blood flow and oxygen delivery to the ischemic areas of the heart, and reduces the pain and discomfort.