A patient with coronary artery disease is to start low-dose aspirin therapy.
What is the primary reason for this medication?

Choice A rationale

Administering a medication when there is a strong possibility the patient has already received it could lead to an overdose. The automated dispensing machine's record indicates removal of the dose, and the patient's statement, despite her confusion, suggests she might have taken it. The nurse's primary responsibility is patient safety and preventing medication errors, which this action would violate.

Choice B rationale

This is the safest course of action. The medication was removed from the machine, and the patient states she thinks she took it. The night shift nurse's failure to sign the MAR is a documentation error, but the potential for a double dose is a serious safety concern. The nurse should hold the dose and investigate further before administering anything to prevent an iatrogenic event.

Choice C rationale

Notifying the provider for a new order is an unnecessary and premature step. The issue is not that the medication is unavailable or the order is incorrect. The immediate concern is whether the patient has already received the dose. Holding the medication and verifying the administration is the correct first step, and the provider would not be contacted unless there was a clinical reason to do so, such as if the blood glucose became dangerously high.

Choice D rationale

Giving the insulin and then monitoring the patient is dangerous. Administering an additional dose of insulin could cause a severe hypoglycemic event, especially in a confused patient. The blood glucose of 142 mg/dL is not critically high, so there is no immediate need for the insulin, and the risk of a medication error outweighs any perceived benefit of administering the medication immediately.

Choice A rationale

Digoxin is a cardiac glycoside that increases myocardial contractility and stroke volume, leading to improved cardiac output. It primarily affects the heart's pumping ability and heart rate, but it is not the main drug used to reduce both preload and afterload. Its role is more to manage symptoms of heart failure and improve cardiac output.

Choice B rationale

ACE inhibitors (e.g., lisinopril) work by blocking the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. This leads to vasodilation, which decreases both systemic vascular resistance (afterload) and venous pressure (preload), making them a cornerstone for treating heart failure and reducing the workload on the heart.

Choice C rationale

Beta-blockers (e.g., carvedilol) block the effects of epinephrine and norepinephrine on beta receptors, leading to a decrease in heart rate and contractility. This reduces myocardial oxygen demand and can improve ventricular remodeling over time in heart failure, but they do not primarily reduce both preload and afterload in the same way as ACE inhibitors.

Choice D rationale

Diuretics (e.g., furosemide) work by increasing the excretion of sodium and water from the body, which reduces blood volume. This primarily reduces preload (volume returned to the heart) and is used to manage symptoms like edema and congestion, but it is not as effective at reducing afterload as ACE inhibitors.