A nurse is reviewing laboratory results for a client who has hypokalemia. Which of the following findings should the nurse expect?
Decreased serum pH.
Increased serum calcium.
Decreased serum magnesium.
Increased serum bicarbonate.
The Correct Answer is C
Choice A: Decreased serum pH. This is incorrect because hypokalemia usually causes increased serum pH, not decreased. This is because low potassium levels can lead to metabolic alkalosis, a condition where the blood is too alkaline due to loss of acid from the body. This can happen in cases of vomiting, diuretic use, or mineralocorticoid excess.
Choice B:
Increased serum calcium. This is incorrect because hypokalemia does not directly affect serum calcium levels. However, hypokalemia can cause hypomagnesemia, or low magnesium levels, which can in turn cause hypercalcemia, or high calcium levels. This is because magnesium is needed for the secretion of parathyroid hormone (PTH), which regulates calcium balance in the body. Low magnesium levels can lead to increased PTH secretion and increased calcium reabsorption from the bones and kidneys.
Choice C:
Decreased serum magnesium. This is correct because hypokalemia and hypomagnesemia often occur together, especially in cases of chronic diarrhea, malabsorption, alcoholism, or diuretic use. This is because potassium and magnesium are both lost in the urine or stool when these conditions are present. Hypomagnesemia can also cause hypokalemia by impairing the reabsorption of potassium in the kidneys and increasing the entry of potassium into the cells.
Choice D:
Increased serum bicarbonate. This is incorrect because hypokalemia usually causes decreased serum bicarbonate, not increased. This is because low potassium levels can lead to metabolic acidosis, a condition where the blood is too acidic due to accumulation of acid in the body. This can happen in cases of diabetic ketoacidosis, renal tubular acidosis, or chronic kidney disease.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Choice A reason:
pH 7.50, PaCO2 40 mm Hg, HCO3- 30 mEq/L. This choice is correct because it shows a high pH, a normal PaCO2, and a high HCO3-, which are consistent with metabolic alkalosis. Metabolic alkalosis occurs when there is a loss of acid or a gain of base in the body fluids, such as from prolonged nasogastric suctioning. The kidneys try to compensate by excreting more bicarbonate, but this process is slow and incomplete.
Choice B reason:
pH 7.35, PaCO2 35 mm Hg, HCO3- 24 mEq/L. This choice is incorrect because it shows normal values for pH, PaCO2, and HCO3-, which indicate no acid-base imbalance. A client with metabolic alkalosis would have an elevated pH and bicarbonate level.
Choice C reason:
pH 7.25, PaCO2 50 mm Hg, HCO3- 26 mEq/L. This choice is incorrect because it shows a low pH, a high PaCO2, and a normal HCO3-, which are consistent with respiratory acidosis. Respiratory acidosis occurs when there is impaired gas exchange or hypoventilation, leading to an accumulation of carbon dioxide in the blood. The kidneys try to compensate by retaining more bicarbonate, but this process is slow and incomplete.
Choice D reason:
pH 7.30, PaCO2 30 mm Hg, HCO3- 18 mEq/L. This choice is incorrect because it shows a low pH, a low PaCO2, and a low HCO3-, which are consistent with metabolic acidosis. Metabolic acidosis occurs when there is a gain of acid or a loss of base in the body fluids, such as from diabetic ketoacidosis or diarrhea. The lungs try to compensate by increasing the rate and depth of breathing to expel more carbon dioxide, but this process is fast and limited.
Correct Answer is A
Explanation
Choice A reason:
Serum glucose 600 mg/dL. This is an expected finding for a client who has diabetic ketoacidosis (DKA) DKA results from a deficiency of insulin, which leads to hyperglycemia and ketosis. The normal range for serum glucose is 70 to 110 mg/dL.
Choice B reason:
Serum bicarbonate 28 mEq/L. This is not an expected finding for a client who has DKA. A client who has DKA experiences ketosis, which results in ketones in the urine and blood. The nurse should expect a client who has DKA to have an HCO3- less than 15 mEq/L. This decreased value is due to an increased production of ketones, which results in metabolic acidosis. The normal range for serum bicarbonate is 22 to 26 mEq/L.
Choice C reason:
Serum potassium 2.5 mEq/L. This is not an expected finding for a client who has DKA. A client who has DKA experiences osmotic diuresis and subsequent dehydration, which can cause electrolyte imbalances. The nurse should expect a client who has DKA to have elevated serum potassium levels due to the movement of potassium from the intracellular to the extracellular space in response to acidosis. The normal range for serum potassium is 3.5 to 5 mEq/L.
Choice D reason:
Serum sodium 150 mEq/L. This is not an expected finding for a client who has DKA. A client who has DKA experiences osmotic diuresis and subsequent dehydration, which can cause electrolyte imbalances. The nurse should expect a client who has DKA to have decreased serum sodium levels due to the dilutional effect of excess glucose in the blood. The normal range for serum sodium is 136 to 145 mEq/L.
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