ATI Fluid Electrolyte and Acid-Base Regulation

Correct Answer: A

Rationale: The correct answer is A: Substantially reduced renal function. In older adults, elevated serum creatinine levels can indicate impaired kidney function, as the kidneys may not filter waste products as efficiently. This can lead to a buildup of creatinine in the blood. Acute kidney injury (Choice B) is a sudden decline in kidney function and would typically present with a more significant increase in creatinine levels. Decreased cardiac output (Choice C) would not directly cause elevated creatinine levels. Alterations in the ratio of body fluids to muscle mass (Choice D) would not be a common cause of elevated creatinine levels in this scenario.

Correct Answer: A

Rationale: The correct answer is A: "I will drink at least three glasses of milk each day." Milk is a good source of calcium and bicarbonate, which can help buffer excess acids in the body and prevent metabolic acidosis. Calcium also plays a role in maintaining the acid-base balance. Option B is incorrect because while eating well-balanced meals is important for overall health, it does not specifically address the prevention of metabolic acidosis. Option C is irrelevant to the prevention of metabolic acidosis. Option D is incorrect because avoiding salting food does not directly address the underlying issue of metabolic acidosis related to malnutrition.

Correct Answer: C

Rationale: Rationale: C is correct because in renal failure, the kidneys lose the ability to regenerate and reabsorb bicarbonate, which is essential for maintaining a stable pH level in the body. B is incorrect because the kidneys primarily regulate pH by controlling bicarbonate levels, not through electrolyte changes. A is incorrect because the kidneys do not regulate carbonic acid in the same way. D is incorrect as it does not accurately describe the process of pH regulation in the kidneys.

Correct Answer: B

Rationale: The correct answer is B: Hypocalcemia. Following a thyroidectomy, there is a risk of damaging the parathyroid glands, leading to hypocalcemia. Symptoms such as tingling in lips and fingers, muscle spasms, and increased muscle tone are classic signs of hypocalcemia. The initial concern should be hypocalcemia due to its potential to cause serious complications such as tetany and laryngospasm. Options A, C, and D are incorrect as they do not align with the symptoms described. Hypophosphatemia may present with weakness and respiratory failure, hypermagnesemia with hypotension and respiratory depression, and hyperkalemia with muscle weakness and cardiac arrhythmias.

Correct Answer: C

Rationale: The correct answer is C: Help distinguish reduced renal blood flow from decreased renal function. Rationale: 1. Oliguria is a decrease in urine output. 2. Fluid challenge with normal saline can help determine the cause of oliguria by assessing the response of the kidneys. 3. If the oliguria improves after the fluid challenge, it suggests reduced renal blood flow as the cause. 4. If oliguria persists, it indicates decreased renal function. Summary: A. Fluid challenge does not directly help in distinguishing between hyponatremia and hypernatremia. B. Evaluating pituitary gland function requires specific tests, not just a fluid challenge. D. Treating hypertension-induced oliguria may involve different interventions, not just a fluid challenge.