Correct Answer: A

Rationale: An INR of 4.5 is elevated, indicating an increased risk of bleeding due to excessive anticoagulation. The most appropriate action for the nurse in this scenario is to administer vitamin K. Vitamin K helps reverse the anticoagulant effects of warfarin, thus lowering the INR and reducing the risk of bleeding. Holding the next dose of warfarin (choice B) is not sufficient to address the immediate high INR level. Increasing the dose of warfarin (choice C) would further elevate the INR, worsening the risk of bleeding. While monitoring the client's INR closely (choice D) is important, immediate action is required to address the critically high INR level, making the administration of vitamin K the priority intervention.

Correct Answer: A

Rationale: The correct answer is A: Stroke volume. Stroke volume refers to the volume of blood ejected by the left ventricle during each heartbeat. This is determined by preload (the degree of stretch of the cardiac muscle fibers at the end of diastole), contractility (the force of myocardial contraction), and afterload (the pressure or resistance that the ventricle must overcome to eject blood). Choice B, Cardiac output, is the volume of blood pumped by the heart per minute and is calculated by multiplying the heart rate by the stroke volume. Choice C, End-diastolic volume, is the volume of blood in the ventricle at the end of diastole before contraction. Choice D, Ejection fraction, is the proportion of blood pumped out of the ventricle with each contraction, calculated by dividing the stroke volume by the end-diastolic volume.

Correct Answer: A

Rationale: The correct answer is A: Avoid foods high in vitamin K. Warfarin is a medication that works by decreasing the activity of vitamin K in the body to prevent blood clotting. Therefore, consuming foods high in vitamin K like green leafy vegetables can interfere with the medication's effectiveness. Choices B, C, and D are incorrect. Increasing the intake of vitamin K-rich foods would counteract the effects of warfarin. Avoiding foods high in protein or increasing the intake of foods high in calcium are not specifically related to the use of warfarin.

Correct Answer: A

Rationale: The correct answer is Angioplasty. Angioplasty is a procedure where a catheter is used to open a blocked or narrowed coronary artery, often involving the placement of a stent to keep the artery open and improve blood flow to the heart. Choice B, Valve replacement, is incorrect as it involves replacing a heart valve, not opening a blocked artery. Choice C, Stent placement, is similar to angioplasty but not as specific, as it does not involve the catheter-based procedure. Choice D, Coronary artery bypass graft (CABG), is a different procedure where blocked arteries are bypassed using a blood vessel from another part of the body.

Correct Answer: A

Rationale: An echocardiogram is the correct answer because it is a diagnostic procedure that uses sound waves to create images of the heart, enabling doctors to assess its structure and function. This imaging technique is specifically designed for cardiac assessment. MRI (Choice B), CT scan (Choice C), and X-ray (Choice D) are imaging modalities that are not primarily used for detailed evaluation of the heart's structure and function, making them incorrect choices for this question.