Correct Answer: D

Rationale: The correct answer is D. A contrast-aided CT scan involves the injection of dye to enhance the images obtained. The dye may cause a warm flushing sensation when injected, which is a common side effect. Choices A, B, and C are incorrect. CT with contrast is generally not a painful procedure, the duration of the test does not usually take 2 to 3 hours, and restrictions on food and fluids are typically before the test, not afterward.

Correct Answer: D

Rationale: Medications with a narrow therapeutic index have a limited range between the therapeutic dose and a toxic dose. It is important to monitor these medications closely by evaluating regular serum peak and trough levels. Drugs with a narrow spectrum (Choice B) are antibiotics that target only a limited group of bacteria, not related to the need for peak and trough monitoring. Drugs with a broad spectrum (Choice A) cover a wide range of bacteria, but this characteristic does not determine the need for peak and trough monitoring. Drugs with a broad therapeutic index (Choice C) have a wide safety margin between therapeutic and toxic doses, so they typically do not require peak and trough level monitoring.

Correct Answer: A

Rationale: The patient's presentation of tachycardia, hypotension, lethargy, muscle weakness, and gastroenteritis suggests hyponatremia. Hyponatremia is characterized by a serum sodium level below the normal range of 135-145 mEq/L. A serum sodium level of 126 mEq/L falls significantly below this range, indicating hyponatremia. Choice B (140 mEq/L) and Choice C (145 mEq/L) are within the normal range for serum sodium levels and would not explain the patient's symptoms. Choice D (158 mEq/L) is above the normal range and would indicate hypernatremia, which is not consistent with the patient's presentation.

Correct Answer: A

Rationale: The correct answer is A. For an EEG, it is essential that the client's hair is clean, without any products like hairspray or gel, to ensure good electrode contact with the scalp. Choice B is not a concern as having breakfast is allowed before the test. Choice C, not taking an anticonvulsant, might be required for certain types of EEGs to capture accurate brain activity. Choice D, not drinking coffee, is not a specific requirement for an EEG preparation.

Correct Answer: A

Rationale: In the scenario presented, the patient is experiencing mild hyperkalemia with a potassium level of 5.4 mEq/L. The appropriate intervention for mild hyperkalemia is a low-potassium diet to restrict potassium intake. This helps in managing and preventing further elevation of potassium levels. Intravenous sodium bicarbonate is not indicated as the patient's sodium level is normal at 140 mEq/L. Kayexalate, a cation-exchange resin, is typically used for severe hyperkalemia to promote potassium excretion. Salt substitutes, which often contain potassium chloride, should be avoided in patients with hyperkalemia as they can exacerbate the condition by increasing potassium levels further.