Correct Answer: A

Rationale: The correct answer is A: Serotonin. Serotonin plays a vital role in mood regulation, and its imbalance is often associated with depression. Many antidepressants function by boosting serotonin levels in the brain. Dopamine (Choice B) is more linked to reward and pleasure pathways in the brain, not primarily targeted for mood regulation. GABA (Choice C) is an inhibitory neurotransmitter that helps reduce neuronal excitability, not primarily associated with mood regulation. Acetylcholine (Choice D) is involved in muscle movement and cognitive functions, not the primary target of antidepressants for mood regulation.

Correct Answer: A

Rationale: The correct intervention for a client with Alzheimer's disease in an extended care facility is to plan to have the same nursing staff provide care whenever possible. Consistency in caregivers helps reduce confusion and anxiety in clients with Alzheimer's disease, promoting a stable and supportive environment for the client. Choice B is incorrect as it focuses on activities rather than the consistency of caregivers. Choice C is incorrect as it suggests isolating the client, which can lead to increased confusion and distress. Choice D is incorrect as introducing the client to new people immediately can be overwhelming and may exacerbate their symptoms.

Correct Answer: A

Rationale: The correct answer is A: 'To prevent deep vein thrombosis (DVT).' Sequential compression devices (SCDs) are primarily used to prevent deep vein thrombosis (DVT) by promoting blood flow in the legs and reducing venous stasis, which is a common risk for post-operative clients who are on bed rest. While SCDs do improve circulation in the legs indirectly, their primary purpose is DVT prevention. Preventing pressure ulcers is typically achieved through repositioning and support surfaces, not with SCDs, making choice C incorrect. SCDs are not used to alleviate post-operative pain, so choice D is also incorrect.

Correct Answer: B

Rationale: Providing a diversionary activity is the most appropriate nursing intervention to promote comfort for a client with pericarditis. This intervention helps to distract the patient and reduce discomfort by focusing their attention elsewhere. Auscultating heart sounds, while important for monitoring the condition, does not directly address the client's comfort. Encouraging deep breathing can be beneficial for some conditions but may not be specifically aimed at promoting comfort in pericarditis. Maintaining a patent intravenous access is essential for treatment access and management of the condition, but it does not directly promote comfort for the client.

Correct Answer: A

Rationale: The rubella vaccine is crucial for preventing rubella infection, which can cause severe congenital disabilities if contracted during pregnancy. Administering the vaccine subcutaneously is the correct action based on EMR documentation. Observing breastfeeding, calling the nursery for blood type results, and administering pain medication are not indicated by the EMR documentation and are not relevant to the situation described in the question.