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:

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.

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.