Correct Answer: A

Rationale: The correct answer is Norepinephrine. Norepinephrine is the neurotransmitter released by the sympathetic nervous system that increases heart rate and the force of contraction. Epinephrine, though similar, is more involved in the fight-or-flight response and has a broader range of effects on various organs. Dopamine is not primarily responsible for increasing heart rate and contractility. Acetylcholine is a neurotransmitter that predominantly acts on the parasympathetic nervous system to decrease heart rate and contractility.

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: Catheter ablation is the correct answer. During catheter ablation, a catheter is used to create a small scar in the heart tissue to block abnormal electrical signals, thereby restoring a normal heart rhythm. Choices B, C, and D are incorrect because angioplasty is a procedure to widen narrowed or obstructed arteries, stent placement involves inserting a mesh tube to support a weak artery, and valve replacement is the surgical procedure of replacing a heart valve, none of which match the description provided in the question.

Correct Answer: A

Rationale: The correct answer is A, Emphysema. Emphysema is a lung condition characterized by the damage to the air sacs (alveoli) in the lungs, which results in breathlessness and reduced lung function. Pulmonary fibrosis (B) is a condition where lung tissue becomes damaged and scarred, leading to stiffness in the lungs. Lung cancer (C) is a malignancy affecting the lungs, which can cause various symptoms depending on the stage. Lung abscess (D) is a localized collection of pus within the lung tissue, typically caused by a bacterial infection.

Correct Answer: A

Rationale: The correct answer is A: Hold the enoxaparin and notify the healthcare provider. Enoxaparin, being an anticoagulant, should be held before surgery to reduce the risk of excessive bleeding during the procedure. It is crucial to inform the healthcare provider to determine the appropriate management plan. Choice B is incorrect because administering enoxaparin before surgery can increase the risk of bleeding. Choice C is incorrect as vitamin K administration is not typically indicated in this situation. Choice D is incorrect because monitoring the client's INR and proceeding with surgery without addressing the enoxaparin can lead to significant bleeding complications.