A patient with a cardiac history is taking the diuretic furosemide (Lasix) and is seen in the emergency for muscle weakness. Which laboratory value does you asses first?

1. A

   Serum albumin

2. B

   Serum sodium

3. C

   Haematocrit

4. D

   Serum potassium

Appeared in: PGIMS Rohtak NO - 2017

Explanation

• Furosemide (Lasix) is a loop diuretic, which is known to cause significant potassium loss through urination.
• Muscle weakness is a classic and primary symptom of hypokalemia (low serum potassium).
• For a patient with a cardiac history, hypokalemia is particularly dangerous because it increases myocardial irritability and the risk of life-threatening dysrhythmias.
• Therefore, assessing the serum potassium level is the most critical and immediate priority to ensure patient safety.

Why Other Options Were Wrong

• Option A: Serum albumin reflects the patient's long-term nutritional status and liver function. It is not acutely affected by furosemide in a way that would cause muscle weakness.
• Option B: While furosemide can also cause sodium loss (hyponatremia), the presenting symptom of muscle weakness is more specific and concerning for hypokalemia. Neurological symptoms like confusion or seizures are more common with severe hyponatremia.
• Option C: Haematocrit measures the percentage of red blood cells in the blood and is an indicator of hydration status. While furosemide can cause dehydration and lead to an elevated haematocrit, this is not the direct cause of muscle weakness.

Related Visual

Clinical Relevance

• Nursing practice connection: Prioritize focused assessment, early escalation, and real-time monitoring when managing Priority nursing assessment for adverse effects of loop diuretics in acute care settings.
• Nurses must prioritize monitoring for hypokalemia in any patient taking a potassium-wasting diuretic like furosemide or thiazides.
• In cardiac patients, especially those on digoxin, hypokalemia significantly increases the risk of digoxin toxicity, which can lead to fatal arrhythmias. The nurse must be vigilant.
• What if the patient was taking spironolactone instead of furosemide? Spironolactone is a potassium-sparing diuretic. In that case, the priority assessment would be for hyperkalemia (high potassium), as muscle weakness can also be a symptom of elevated potassium levels.

How to Approach the Question

• First, identify the drug mentioned in the question: furosemide (Lasix).
• Recall the pharmacological class of this drug: It is a loop diuretic.
• Identify the primary and most common adverse effects of this drug class. Loop diuretics are known for causing significant electrolyte loss, especially potassium.
• Analyze the patient's presenting symptom: muscle weakness. Connect this symptom to the known side effects of the drug.
• Recognize that muscle weakness is a hallmark sign of hypokalemia (low potassium).
• Prioritize the laboratory test that directly measures the suspected electrolyte imbalance. Therefore, assessing serum potassium is the first and most critical action.

Concept Tested & Keywords

• Concept Tested: Priority nursing assessment for adverse effects of loop diuretics
• Stem keywords: cardiac history, furosemide (Lasix), diuretic, muscle weakness
• Lead-in keywords: asses first
• Clinical cues: The combination of furosemide use and muscle weakness strongly points towards hypokalemia.

Question ID

Q_xximzjCoxa9F8-0qqU_X

Copy ID

Reference Book

E6 Pharmacology Nursing Lilley 11e Part 2 pp. 169-171, 156-158, 153-155