The nurse is caring for a patient who has been vomiting and has diarrhea for 3 days and now has muscle weakness and paresthesias in his hands and feet, along with an irregular pulse rate and rhythm, and shallow respirations with crackles on auscultation of his lungs bilaterally. The nurse suspects that these symptoms are most likely due to which electrolyte imbalance?

Choice A: Hypercalcemia. This is a condition of having too much calcium in the blood. It can cause muscle weakness, constipation, nausea, vomiting, confusion, and irregular heartbeat. However, it does not typically cause paresthesias (tingling or numbness), diarrhea, or crackles in the lungs.

Choice B:

Hypokalemia. This is a condition of having too low potassium in the blood. It can cause muscle weakness, paresthesias, irregular heartbeat, shallow respirations, and increased risk of digoxin toxicity (a medication used to treat heart failure) It can also cause vomiting and diarrhea, which can worsen the potassium loss. This choice matches the symptoms of the patient.

Choice C:

Hypermagnesemia. This is a condition of having too much magnesium in the blood. It can cause muscle weakness, nausea, vomiting, low blood pressure, bradycardia (slow heart rate), and respiratory depression. However, it does not usually cause paresthesias, diarrhea, or crackles in the lungs.

Choice D:

Hypophosphatemia. This is a condition of having too low phosphate in the blood. It can cause muscle weakness, bone pain, rickets (softening of bones), and impaired cellular function. However, it does not typically cause paresthesias, irregular heartbeat, shallow respirations, or crackles in the lungs.

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.