# Situation: A 72-year-old woman with heart failure with reduced ejection fraction (left ventricular ejection fraction 30%) is admitted to the medical ward for worsening shortness of breath and leg edema. Her home medications are furosemide 40 mg twice daily, digoxin 0.125 mg daily, carvedilol 6.25 mg twice daily, and spironolactone 25 mg daily. She weighs 64 kg on admission. Before discharge, her serum potassium is 4.6 mEq/L (4.6 mmol/L), and she will continue all four home medications. The nurse reviews her medications and diet with her. Which statement by the client shows a need for **FURTHER** teaching?

> source: MyMerci (mymerci.kr)  
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> subject: Nursing Practice III — Care of Clients with Problems in Surgery, Oxygenation, Fluid and Electrolytes, Infectious, Inflammatory and Immunologic Response, Cellular Aberrations

## 문제

Situation: A 72-year-old woman with heart failure with reduced ejection fraction (left ventricular ejection fraction 30%) is admitted to the medical ward for worsening shortness of breath and leg edema. Her home medications are furosemide 40 mg twice daily, digoxin 0.125 mg daily, carvedilol 6.25 mg twice daily, and spironolactone 25 mg daily. She weighs 64 kg on admission.

Before discharge, her serum potassium is 4.6 mEq/L (4.6 mmol/L), and she will continue all four home medications. The nurse reviews her medications and diet with her. Which statement by the client shows a need for **FURTHER** teaching?

## 보기

1. "I will rest between chores and stop if I become short of breath."
2. "I will call the clinic if I gain 1 kg in a day or 2 kg in a week."
3. "I will take paracetamol, not ibuprofen, when my knees hurt."
4. "I will season my food with a low-sodium salt substitute instead." **✔ 정답**

**정답: 4**

## 해설

Low-sodium salt substitutes usually replace sodium with potassium chloride. Because she takes spironolactone, a potassium-sparing mineralocorticoid receptor antagonist, added potassium can cause dangerous hyperkalemia, so salt substitutes are avoided unless prescribed. The other statements are correct heart failure self-care.

## 심화 해설

Understanding the Risk: Potassium-Sparing Diuretics and Salt Substitutes

The client is receiving spironolactone, a mineralocorticoid receptor antagonist that works in the distal nephron to block aldosterone. This promotes sodium and water excretion while conserving potassium. Because of this mechanism, spironolactone is classified as a potassium-sparing diuretic. The client’s serum potassium of 4.6 mEq/L is within normal limits on admission, but the risk for hyperkalemia remains significant while continuing this medication.

Many commercial low-sodium salt substitutes replace sodium chloride with potassium chloride. For a patient taking spironolactone, adding dietary potassium from a salt substitute can overwhelm the kidney’s already reduced ability to excrete potassium. The combination of a potassium-sparing diuretic and a potassium-based salt substitute can precipitate dangerous hyperkalemia, including fatal arrhythmias. Therefore, salt substitutes are avoided unless specifically prescribed and monitored by the provider.

In acute heart failure, the clinical priority is to relieve congestion while avoiding electrolyte derangements and arrhythmias [1]. The patient’s regimen includes three medications that influence potassium balance: furosemide promotes potassium loss, while spironolactone and the ACE inhibitor or ARB (commonly part of HFrEF therapy) tend to retain potassium. The net balance can shift quickly with dietary changes. Watch out! A potassium level that is normal today does not guarantee safety tomorrow if the patient begins using a potassium-containing salt substitute.

Why the Other Statements Are Correct

Each of the other three options reflects appropriate heart failure self-care and does not require further teaching.

| Statement | Rationale |
| --- | --- |
| “I will rest between chores and stop if I become short of breath.” | Energy conservation and activity pacing reduce myocardial oxygen demand and prevent symptom exacerbation in heart failure. |
| “I will call the clinic if I gain 1 kg in a day or 2 kg in a week.” | Rapid weight gain indicates fluid retention and worsening congestion, requiring prompt diuretic adjustment or clinical evaluation. |
| “I will take paracetamol, not ibuprofen, when my knees hurt.” | NSAIDs such as ibuprofen promote sodium and water retention, reduce the effectiveness of diuretics, and can worsen renal function in heart failure. |

Clinical Application for the Nursing Examinee

The key distinction is between sodium restriction and potassium loading. The client correctly understands the need to limit sodium, but she has chosen a method that introduces a different electrolyte hazard. In a patient taking spironolactone, the safest approach to flavoring food is to use herbs, spices, lemon juice, or vinegar rather than a potassium-based salt substitute.

Key point! When reviewing medications with a heart failure patient, always ask specifically about salt substitutes, because many patients do not recognize them as a source of potassium. This is a high-yield safety item for licensure examinations and for clinical practice.

The statement about using a low-sodium salt substitute demonstrates a need for further teaching because it reflects an incomplete understanding of the interaction between spironolactone and potassium chloride, placing the client at risk for life-threatening hyperkalemia [1].References (research sources)

- [1]Diagnosis and management of acute heart failure.Research articleUral D, Çavuşoğlu Y, Eren M, Karaüzüm K, Temizhan A, Yılmaz MB, Zoghi M, Ramassubu K, Bozkurt B. (2015) · DOI: 10.5152/anatoljcardiol.2015.6567

## 임상 시나리오

Potassium-Sparing Diuretics and Salt SubstitutesAvoiding Hidden Potassium in Heart Failure
Spironolactone blocks aldosterone in the distal nephron, promoting sodium and water excretion while conserving potassium. This places the patient at risk for hyperkalemia, especially when dietary potassium intake increases.

Low-sodium salt substitutes typically replace sodium chloride with potassium chloride. For a patient on spironolactone, this added potassium can overwhelm the kidney's reduced excretory capacity, leading to dangerous hyperkalemia and potentially fatal arrhythmias.

CautionA normal serum potassium of 4.6 mEq/L does not eliminate risk. The combination of a potassium-sparing diuretic and a potassium-based salt substitute can shift potassium balance rapidly. Salt substitutes should be avoided unless specifically prescribed and monitored.

## 핵심 개념

- **Spironolactone** — A potassium-sparing diuretic that blocks aldosterone, promoting sodium and water excretion while conserving potassium.
- **Hyperkalemia** — An elevated serum potassium level that can cause life-threatening cardiac arrhythmias.
- **Salt Substitute** — A product that replaces sodium chloride with potassium chloride, increasing dietary potassium intake.
- **Heart Failure with Reduced Ejection Fraction** — A type of heart failure where the left ventricular ejection fraction is 40% or less, impairing the heart's pumping ability.
- **NSAIDs** — Nonsteroidal anti-inflammatory drugs that can promote sodium and water retention, worsening heart failure symptoms.

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