A client is taking furosemide (Lasix) for management of mild hypertension. The nurse knows to assess laboratory results for a side effect of this diuretic. Select the lab value that matches a common side effect of this medication.

Choice A reason: A serum potassium level of 5.6 mEq/L is not a common side effect of furosemide, but of hyperkalemia. Hyperkalemia is a condition where the blood potassium level is too high. It can cause muscle weakness, irregular heartbeat, and cardiac arrest. Furosemide is a loop diuretic that increases the urinary excretion of water, sodium, chloride, and potassium. It can cause hypokalemia, which is a low blood potassium level, not hyperkalemia.

Choice B reason: A serum sodium level of 142 mEq/L is not a common side effect of furosemide, but of normal sodium level. The normal range of serum sodium level is 135 to 145 mEq/L. Sodium is an electrolyte that helps regulate the fluid balance, nerve impulses, and muscle contractions in the body. Furosemide can cause hyponatremia, which is a low blood sodium level, but not a normal sodium level.

Choice C reason: A serum sodium level of 138 mEq/L is also not a common side effect of furosemide, but of normal sodium level. As explained in choice B, the normal range of serum sodium level is 135 to 145 mEq/L. Furosemide can cause hyponatremia, which is a low blood sodium level, but not a normal sodium level.

Choice D reason: A serum potassium level of 2.8 mEq/L is a common side effect of furosemide, and of hypokalemia. Hypokalemia is a condition where the blood potassium level is too low. It can cause muscle cramps, fatigue, weakness, arrhythmias, and paralysis. Furosemide is a loop diuretic that increases the urinary excretion of water, sodium, chloride, and potassium. It can cause hypokalemia, which is a low blood potassium level. The nurse should monitor the client's serum potassium level and signs of hypokalemia, and advise the client to eat potassium-rich foods, such as bananas, oranges, and potatoes. The nurse should also report the lab value to the prescriber, who may adjust the dose of furosemide or prescribe a potassium supplement.

Choice A reason: This statement is false. Glucose: 88 mg/dL is a normal blood sugar level and does not indicate any problem with fluid or electrolyte balance¹.

Choice B reason: This statement is false. WBCs: 4000 is slightly below the normal range, but not significantly low. It may indicate a mild infection or inflammation, but not a serious fluid or electrolyte imbalance².

Choice C reason: This statement is false. K+: 3.4 mEq/L is slightly below the normal range, but not dangerously low. It may indicate a mild potassium deficiency, which can cause muscle weakness, but not restlessness or agitation.

Choice D reason: This statement is true. Na+: 154 mEq/L is above the normal range and indicates hypernatremia, or high blood sodium level. This can cause dehydration, confusion, restlessness, agitation, and seizures. It is a medical emergency that requires immediate treatment. Continuous tube feedings can increase the risk of hypernatremia if the formula is too concentrated or the fluid intake is inadequate⁵.