The nurse is monitoring a patient who has a central venous catheter in place for signs of complications. Which of the following are potential complications of central venous catheters? (Select all that apply.)

Choice A reason:

Serum sodium is not directly related to the acid-base balance of the body. Sodium bicarbonate therapy does not affect the serum sodium level significantly. Therefore, monitoring serum sodium is not an effective way to evaluate the effectiveness of the therapy.

Choice B reason:

Serum potassium is inversely related to the serum pH. As the pH increases, the potassium level decreases, and vice versa. Sodium bicarbonate therapy raises the pH and lowers the potassium level. Therefore, monitoring serum potassium is important to prevent hypokalemia, but it does not directly reflect the acid-base balance of the body.

Choice C reason:

Serum chloride is inversely related to the serum bicarbonate level. As the bicarbonate level increases, the chloride level decreases, and vice versa. Sodium bicarbonate therapy increases the bicarbonate level and decreases the chloride level. Therefore, monitoring serum chloride is important to prevent hypochloremia, but it does not directly reflect the acid-base balance of the body.

Choice D reason:

Serum bicarbonate is directly related to the acid-base balance of the body. The normal range of serum bicarbonate is 22 to 26 mEq/L. In metabolic acidosis, the bicarbonate level is low, and in metabolic alkalosis, it is high. Sodium bicarbonate therapy aims to increase the bicarbonate level and correct metabolic acidosis. Therefore, monitoring serum bicarbonate is the most effective way to evaluate the effectiveness of the therapy.

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.