Correct Answer: B

Rationale: The correct answer is B: Spironolactone. Spironolactone is a potassium-sparing diuretic that can lead to hyperkalemia. With potassium levels already elevated at 6.2 mEq/L, withholding Spironolactone is essential to prevent further increase in potassium levels, which could result in dangerous cardiac arrhythmias. Losartan (Choice A) is an angiotensin receptor blocker and does not directly affect potassium levels. Metoprolol (Choice C) is a beta-blocker and also does not impact potassium levels significantly. Furosemide (Choice D) is a loop diuretic that can actually lower potassium levels, so it would not be the medication to withhold in this case.

Correct Answer: D

Rationale: When caring for a client with active tuberculosis, it is crucial to implement negative pressure rooms and contact precautions to prevent the spread of infection. Choice A, initiating protective environment precautions, is incorrect as this is not the recommended approach for tuberculosis. Choice B, using droplet precautions only, is insufficient as tuberculosis requires additional precautions. Choice C, ensuring a positive pressure environment in the room, is incorrect because negative pressure rooms are necessary to contain airborne pathogens like tuberculosis. Therefore, the most appropriate measures include implementing negative pressure rooms and contact precautions.

Correct Answer: C

Rationale: The correct answer is C: 'NPO reduces the risk of aspiration during surgery.' When a client is NPO (nothing by mouth) before surgery, it is to prevent aspiration, which can lead to serious complications such as pneumonia. Choice A is incorrect because being NPO is more about preventing aspiration than nausea. Choice B is a general statement without specifying the reason for being NPO. Choice D is partially correct but does not emphasize the crucial aspect of preventing aspiration, which is the primary reason for fasting before surgery.

Correct Answer: B

Rationale: The best response for a client with schizophrenia experiencing auditory hallucinations is to acknowledge the client's feelings and ask what the voices are saying. This approach helps build rapport with the client, demonstrates empathy, and allows the nurse to assess the content of the hallucinations. Understanding the content is crucial to determine whether the client is at risk of harm. Encouraging the client to ignore the voices (Choice A) may invalidate their experience. Redirecting the conversation (Choice C) may not address the underlying issue of the hallucinations. Offering reassurance (Choice D) without understanding the content may overlook potential risks.

Correct Answer: C

Rationale: The correct answer is C, 'Highly protein-bound.' Drugs that are highly protein-bound can displace from protein-binding sites, leading to increased free drug levels in the blood, which can result in toxicity. Monitoring the client for toxicity is crucial when administering highly protein-bound drugs. Choices A, B, and D are incorrect. A short half-life does not necessarily indicate a need for monitoring toxicity; a high therapeutic index indicates a wide safety margin between the effective dose and the toxic dose, reducing the risk of toxicity; low bioavailability refers to the fraction of the drug that reaches the systemic circulation unchanged and does not directly relate to the risk of toxicity.