Final answer:
The nurse should monitor serum potassium levels when a patient is prescribed diuretics for heart failure, due to the risk of hypokalemia caused by increased excretion of potassium along with Na+ and Cl- ions.
Step-by-step explanation:
When a patient is prescribed diuretics for the treatment of heart failure, the nurse should pay particular attention to the serum potassium levels. Diuretics, especially loop diuretics, work by inhibiting the reabsorption of sodium (Na+) and chloride (Cl-) ions in the loop of Henle within the kidneys. This action of loop diuretics leads to increased urination, as water follows the excreted Na+ and Cl- to maintain osmotic balance, which can inadvertently lead to disturbances in the electrolyte balance within the body, particularly potassium levels.
It is critical to monitor serum potassium because diuretics can cause hypokalemia, a condition where potassium levels in the blood are too low. Hypokalemia can lead to dangerous irregularities in heart rhythm and muscle function. Thus, monitoring serum potassium is essential to ensure that the patient remains within a safe range while undergoing diuretic therapy for heart failure.