Correct Answer: A

Rationale: Monitoring the Prothrombin time (PT) and international normalized ratio (INR) is crucial for assessing the effectiveness of warfarin therapy. These tests help determine the clotting ability of the blood and ensure that the client is within the desired therapeutic range to prevent clotting events or bleeding complications. Activated partial thromboplastin time (aPTT) (Choice B) is more commonly used to monitor heparin therapy, not warfarin. Complete blood count (CBC) (Choice C) and fibrinogen levels (Choice D) do not directly assess the effectiveness of warfarin therapy in the same way that PT and INR do.

Correct Answer: A

Rationale: If chest pain persists after the first dose of nitroglycerin, it is appropriate to administer a second dose while continuing to monitor the client's response. Nitroglycerin helps dilate blood vessels and improve blood flow to the heart, relieving chest pain associated with coronary artery disease. Reassessing the client's response to a second dose is crucial before considering other interventions like contacting the healthcare provider or providing additional medications. Administering another dose of nitroglycerin aligns with the standard protocol for managing ongoing chest pain in clients with CAD.

Correct Answer: B

Rationale: When a client with a history of angina pectoris experiences chest pain while ambulating, the priority action for the nurse is to assist the client to sit or lie down. This helps reduce the demand on the heart by decreasing physical exertion. Checking vital signs, administering medication, or applying oxygen can follow once the client is in a more comfortable position. Checking vital signs (Choice A) may be important but addressing the immediate discomfort by positioning the client comfortably takes precedence. Administering sublingual nitroglycerin (Choice C) is appropriate but should come after ensuring the client's comfort. Applying nasal oxygen (Choice D) can be beneficial, but it should not be the first action; assisting the client to sit or lie down is the initial priority.

Correct Answer: B

Rationale: Prothrombin time (PT) and international normalized ratio (INR) are the laboratory values used to monitor the effectiveness of warfarin therapy. These values help ensure that the client is within the therapeutic range for anticoagulation. PT measures the time it takes for blood to clot, while INR standardizes PT results to minimize variations between laboratories. Monitoring these values is crucial to prevent complications such as bleeding or clot formation. Activated partial thromboplastin time (aPTT) (Choice A) is more commonly used to monitor heparin therapy. Platelet count (Choice C) assesses the number of platelets in the blood and is not specific to warfarin therapy. Erythrocyte sedimentation rate (ESR) (Choice D) is a non-specific marker of inflammation and is not used to monitor the effectiveness of warfarin therapy.

Correct Answer: C

Rationale: The correct answer is C: Bed rest, with elevation of the affected extremity. Elevating the affected extremity is crucial in managing thrombophlebitis as it helps reduce swelling and promotes venous return. By elevating the affected extremity, the gravitational force assists in venous blood flow back to the heart, thereby reducing the risk of complications associated with thrombophlebitis. Choices A, B, and D are incorrect because they do not address the need for elevation, which is specifically beneficial in the management of thrombophlebitis.