Correct Answer: B

Rationale: The correct answer is B: fluid replacement with 0.45% saline. The patient's symptoms suggest dehydration and hypovolemia, indicated by low blood pressure, elevated heart rate, and lack of urine output. Fluid replacement with isotonic saline would help restore intravascular volume and improve blood pressure. Blood transfusion (A) is not indicated without evidence of significant blood loss. Inotropic agents (C) are used to improve cardiac function, which is not the primary issue in this case. Antiemetics (D) may help with nausea and vomiting but do not address the underlying cause of hypovolemia.

Correct Answer: B

Rationale: The correct answer is B: fluid replacement with 0.45% saline. The patient's symptoms suggest dehydration and hypovolemia, indicated by low blood pressure, elevated heart rate, and lack of urine output. Fluid replacement with isotonic saline would help restore intravascular volume and improve blood pressure. Blood transfusion (A) is not indicated without evidence of significant blood loss. Inotropic agents (C) are used to improve cardiac function, which is not the primary issue in this case. Antiemetics (D) may help with nausea and vomiting but do not address the underlying cause of hypovolemia.

Correct Answer: C

Rationale: Rationale: Acute tubular necrosis (ATN) is the most common intrarenal condition causing acute kidney injury. ATN is characterized by damage to the renal tubules due to ischemia or nephrotoxic substances. Prolonged ischemia (choice A) and exposure to nephrotoxic substances (choice B) can lead to ATN. Hypotension for several hours (choice D) can result in ischemic injury, which may lead to ATN but is not the direct cause. Therefore, choice C is correct as it directly relates to the primary intrarenal condition of ATN.

Correct Answer: A

Rationale: The correct answer is A. By evaluating the morning laboratory results and reporting abnormal results, the nurse can ensure the patient's safety during dialysis by addressing any concerning findings promptly. This step is crucial in monitoring the patient's condition and adjusting the treatment plan as needed. Incorrect choices: B: Administering antihypertensive medications is not directly related to the patient's dialysis procedure and does not address the immediate needs of the patient in the critical care unit. C: While assessing the dialysis access site is important, reporting abnormalities alone may not be sufficient without a comprehensive evaluation of the patient's laboratory results. D: Weighing the patient to monitor fluid status is important in the context of dialysis, but it is not as critical as evaluating laboratory results for immediate intervention.

Correct Answer: C

Rationale: The correct answer is C because the patient was recently discharged after a prolonged course of aminoglycoside therapy, which is a known risk factor for acute kidney injury due to its nephrotoxic effects. Choice A is incorrect because although aminoglycosides can cause kidney injury, the duration of therapy is shorter in this case. Choice B is incorrect because controlled hypertension is not a significant risk factor for acute kidney injury. Choice D is incorrect because fluid overload from heart failure may lead to other complications but is not directly associated with acute kidney injury.