A patient with cardiac history is taking the diuretic lasix and is seen in emergency department for muscle weakness. Which lab value do you assess first?

1. A

   Serum albumin

2. B

   Serum sodium

3. C

   Serum potassium

4. D

   Haemactocrit

Appeared in: RAK Nursing Officer - 2019

Explanation

• Lasix (furosemide) is a loop diuretic, a class of drugs known for causing significant potassium loss (potassium-wasting).
• Muscle weakness is a hallmark clinical manifestation of hypokalemia (low serum potassium).
• For patients with a pre-existing cardiac history, hypokalemia poses a high risk of developing dangerous cardiac dysrhythmias.
• Therefore, assessing the serum potassium level is the most critical first step to confirm the suspected cause of the patient's symptoms and guide immediate treatment.

Why Other Options Were Wrong

• Option A: Serum albumin measures protein levels and reflects long-term nutritional status or liver/kidney disease. It is not acutely affected by a single dose of a diuretic and does not cause muscle weakness in this context.
• Option B: While loop diuretics can also cause sodium loss (hyponatremia), the presenting symptom of muscle weakness is more classically and urgently associated with hypokalemia. Neurological symptoms like confusion or seizures are more typical for severe hyponatremia.
• Option D: Hematocrit measures the concentration of red blood cells, which is primarily used to assess for anemia or changes in hydration status. While Lasix can cause dehydration and a subsequent increase in hematocrit (hemoconcentration), this does not cause 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 (furosemide) in acute care settings.
• Nurses must educate patients on potassium-wasting diuretics about the signs of hypokalemia (muscle weakness, fatigue, palpitations) and the importance of consuming potassium-rich foods like bananas, oranges, and potatoes.
• In the hospital setting, any patient on a loop diuretic, especially if they are NPO (nothing by mouth) or have other losses (like diarrhea), requires routine monitoring of their serum potassium levels.
• Patient safety is paramount. For a symptomatic cardiac patient, this lab result is critical for immediate intervention, which may include oral or IV potassium replacement and placing the patient on a cardiac monitor.

How to Approach the Question

• First, identify the key elements in the clinical scenario: the patient has a cardiac history, is taking Lasix (furosemide), and presents with muscle weakness.
• Recall the drug class and primary mechanism of action for Lasix. It's a loop diuretic.
• Connect the drug's action to its known, common side effects. Loop diuretics are famous for 'wasting' potassium.
• Link the primary side effect (potassium loss) to the patient's presenting symptom (muscle weakness), which is a classic sign of hypokalemia.
• Consider the patient's cardiac history, which elevates the risk associated with potassium abnormalities. Hypokalemia can cause life-threatening arrhythmias.
• Based on this chain of reasoning, conclude that assessing the serum potassium level is the most urgent and logical first step.

Concept Tested & Keywords

• Concept Tested: Priority nursing assessment for adverse effects of loop diuretics (furosemide).
• Stem keywords: cardiac history, diuretic, lasix, furosemide, muscle weakness, emergency department
• Lead-in keywords: assess first
• Clinical cues: The combination of Lasix use and muscle weakness strongly points towards an electrolyte imbalance, specifically potassium.
• Clinical cues: The patient's cardiac history makes correcting potential hypokalemia an urgent priority to prevent arrhythmias.

Question ID

Q4zcjwih1Gjgi88JCaC3jk

Copy ID

Reference Book

E6 Pharmacology Nursing Lilley 11e Part 2 pp. 169-171, 153-155, 172-174