Correct Answer: A

Rationale: The correct answer is to hold the digoxin and notify the healthcare provider. A potassium level of 2.8 mEq/L indicates hypokalemia, which can increase the risk of digoxin toxicity. Holding the medication and informing the healthcare provider is crucial to prevent adverse effects. Choice B is incorrect because increasing the dose of digoxin would further raise the risk of toxicity. Choice C is incorrect as continuing the current dose could exacerbate the toxicity risk. Choice D is incorrect because administering potassium supplements alone is not sufficient to address the potential digoxin toxicity; the first step should be to hold the digoxin and seek further guidance.

Correct Answer: A

Rationale: The correct answer is A: Ischemic stroke. Ischemic stroke occurs when a blood clot blocks an artery supplying blood to the brain, leading to brain damage. Choice B, Hemorrhagic stroke, is caused by bleeding in the brain, not a blockage. Choice C, Transient ischemic attack, is a temporary blockage of blood flow to the brain with symptoms similar to a stroke but typically lasting only a few minutes. Choice D, Embolism, refers to a blood clot or other particle that travels through the bloodstream and blocks a blood vessel.

Correct Answer: A

Rationale: The correct answer is A, the carotid body. The carotid body is the major chemoreceptor of the heart responsible for detecting changes in blood oxygen, carbon dioxide, and pH levels. This specialized structure helps regulate the cardiovascular system's response to maintain appropriate oxygen levels in the blood. Choices B, C, and D are incorrect as they are not directly involved in chemoreception in the heart. The aortic body is primarily involved in blood pressure regulation, the vagus nerve is a cranial nerve responsible for parasympathetic innervation, and the SA node is known as the heart's natural pacemaker.

Correct Answer: A

Rationale: Mitral regurgitation is the correct answer. It occurs when the mitral valve does not close properly, allowing blood to flow backward into the left atrium. This condition can lead to symptoms such as fatigue, shortness of breath, and if left untreated, it can progress to heart failure. Aortic stenosis (choice B) is a different heart valve condition characterized by narrowing of the aortic valve, restricting blood flow from the heart. Tricuspid regurgitation (choice C) involves the tricuspid valve not closing properly, leading to blood flowing back into the right atrium. Pulmonary hypertension (choice D) is a condition characterized by high blood pressure in the arteries of the lungs.

Correct Answer: A

Rationale: Thoracentesis is the correct answer. It is a procedure where a needle is inserted into the pleural space to drain fluid, relieving pressure and helping the patient breathe more easily. Bronchoscopy (choice B) is a procedure used to examine the airways, not to drain fluid. An echocardiogram (choice C) is an imaging test to assess the heart's structure and function, not related to draining pleural fluid. A CT scan (choice D) is a cross-sectional imaging test that provides detailed pictures of the inside of the body, not used for draining pleural fluid.