# A nurse is assessing a 68-year-old patient who has been receiving furosemide therapy for heart failure. Which assessment finding would be the priority concern indicating a serious electrolyte imbalance?

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## 문제

A nurse is assessing a 68-year-old patient who has been receiving furosemide therapy for heart failure. Which assessment finding would be the priority concern indicating a serious electrolyte imbalance?

## 보기

1. Muscle cramps in the lower extremities
2. Mild confusion and irritability
3. Decreased urine output over 8 hours
4. Cardiac arrhythmias on telemetry monitor **✔ 정답**

**정답: 4**

## 해설

Cardiac arrhythmias are the most serious and life-threatening manifestation of electrolyte imbalances, particularly hypokalemia and hypomagnesemia, which are common with furosemide therapy. Other findings like muscle cramps or confusion are concerning but not immediately life-threatening.

## 심화 해설

Clinical Reasoning and Priority Setting

When a patient is receiving a loop diuretic like furosemide, the most common expectation is hypokalemia due to potassium wasting in the distal tubules. However, the question asks for the assessment finding that indicates a serious electrolyte imbalance requiring the highest priority. In nursing prioritization, the airway, breathing, and circulation (ABCs) framework dictates that a threat to circulation—specifically a lethal cardiac rhythm—takes precedence over neuromuscular or neurological symptoms.

Pathophysiology and Electrolyte Disruption

Furosemide inhibits the sodium-potassium-chloride cotransporter in the thick ascending limb of the loop of Henle. This action increases the delivery of sodium to the distal nephron, where sodium is reabsorbed in exchange for potassium, leading to urinary potassium loss. While hypokalemia is the typical concern, the clinical scenario can be complicated by acute kidney injury or excessive potassium supplementation, potentially leading to hyperkalemia. Hyperkalemia is defined as a serum potassium level greater than 5.0 mEq/L [1]. As potassium rises, the resting membrane potential of cardiac myocytes becomes less negative, initially increasing excitability but subsequently depressing it, which slows conduction and predisposes the heart to re-entrant arrhythmias.

Analysis of Assessment Findings

| Option | Assessment Finding | Clinical Significance |
| --- | --- | --- |
| 1 | Muscle cramps in the lower extremities | Common with mild hypokalemia or hypomagnesemia; uncomfortable but not immediately life-threatening. |
| 2 | Mild confusion and irritability | Can occur with severe electrolyte shifts, such as extreme hyperkalemia (lethargy, confusion) as noted in the case of a patient with a potassium level of 9.7 mEq/L [1]; however, neurological changes are a late and less specific finding compared to direct cardiac effects. |
| 3 | Decreased urine output over 8 hours | May signal renal hypoperfusion or acute kidney injury, which can exacerbate hyperkalemia, but it is a contributing factor rather than a direct sign of a current lethal electrolyte imbalance. |
| 4 | Cardiac arrhythmias on telemetry monitor | Direct evidence of a life-threatening physiological instability. Severe hyperkalemia exceeding 6.5 mEq/L can lead to cardiac conduction abnormalities, including peaked T-waves, loss of P-waves, widened QRS complexes, and ultimately ventricular fibrillation or asystole if untreated [1]. |

Why Cardiac Arrhythmias Are the Priority

The presence of cardiac arrhythmias on a telemetry monitor is a direct manifestation of a critical disruption in myocardial conduction. In the context of a patient on furosemide, this could stem from either profound hypokalemia or, if renal function is compromised, severe hyperkalemia. The cited evidence underscores that severe cases of hyperkalemia can precipitate life-threatening arrhythmias and cardiac arrest if left untreated [1]. Because arrhythmias represent an immediate threat to cardiac output and effective circulation, they constitute the most urgent assessment finding. The nurse must recognize this as a priority concern over muscle cramps, mental status changes, or diminished urine output, all of which require intervention but do not pose the same imminent risk of mortality.References (research sources)

- [1]Severe Hyperkalemia With Cardiac Conduction Abnormalities in a 92-Year-Old Woman: First Reported Case in Illinois, United States.Research articleAdedara VO, Kholoki S, Kassar K, Amaechi CC, Okei J, Ojo OA, Modise O, Ashuarrah BE. (2025) · DOI: 10.7759/cureus.95662

## 임상 시나리오

Clinical Practice Guide: Monitoring for Electrolyte Imbalances in Patients on Loop Diuretics

**Scenario:** A 68-year-old patient with heart failure on furosemide therapy presents with new-onset cardiac arrhythmias on telemetry.

1. Immediate Nursing Actions

- **Assess the Patient:** Immediately evaluate the patient's level of consciousness, airway, breathing, and circulation (ABCs). Check vital signs, including pulse rate and rhythm, blood pressure, and oxygen saturation.

- **Verify the Rhythm:** Confirm the arrhythmia on the monitor is real and not artifact. Obtain a 12-lead ECG if ordered and time permits, but do not delay treatment for a symptomatic, unstable patient.

- **Activate Emergency Response:** If the patient is unstable (e.g., hypotensive, chest pain, altered mental status), call the Rapid Response Team or activate the facility's emergency protocol immediately.

2. Diagnostic Workup

- **STAT Labs:** Prioritize a basic metabolic panel (BMP) to check serum potassium, sodium, creatinine, and BUN. A serum potassium level should be obtained urgently.

- **Interpret Potassium Levels:**

- **Hypokalemia (<3.5 mEq/L):** Commonly expected with furosemide. Can cause U waves, flattened T waves, and ST depression on ECG.

- **Hyperkalemia (>5.0 mEq/L):** Can occur with acute kidney injury or over-supplementation. ECG changes include peaked T waves, loss of P waves, and widened QRS complex, which can deteriorate into ventricular fibrillation or asystole.

- **Other Labs:** Check magnesium levels, as hypomagnesemia often coexists with hypokalemia and can exacerbate arrhythmias.

3. Anticipated Medical Interventions

- **For Unstable Hyperkalemia:** Prepare to administer IV calcium gluconate or calcium chloride to stabilize the cardiac membrane. Anticipate orders for IV insulin with dextrose, IV sodium bicarbonate, or a beta-agonist (e.g., albuterol) to shift potassium intracellularly. Prepare for emergent hemodialysis if ordered.

- **For Unstable Hypokalemia:** Anticipate orders for IV potassium chloride replacement with continuous cardiac monitoring. Never administer IV potassium as a bolus.

- **Hold Furosemide:** The diuretic will likely be held until the electrolyte imbalance is corrected and the patient is stable.

4. Ongoing Monitoring and Patient Safety

- **Continuous Telemetry:** Maintain continuous cardiac monitoring to observe for rhythm changes during treatment.

- **Frequent Vital Signs:** Monitor blood pressure and heart rate every 5-15 minutes during an acute event.

- **Fall Risk Precautions:** Patients with arrhythmias or muscle weakness from electrolyte shifts are at high risk for falls. Keep the bed in the lowest position and the call light within reach.

- **Documentation:** Document the time of arrhythmia onset, the patient's symptoms, nursing actions taken, provider notifications, and the patient's response to interventions.

**Reference:** Priority setting follows the ABC (Airway, Breathing, Circulation) framework. A cardiac arrhythmia represents a direct threat to circulation and is the highest priority assessment finding in a patient with a potential electrolyte imbalance.

## 핵심 개념

- **Furosemide** — A loop diuretic that inhibits the sodium-potassium-chloride cotransporter in the thick ascending limb of the loop of Henle, leading to increased excretion of potassium.
- **Hypokalemia** — A serum potassium level less than 3.5 mEq/L, often caused by loop diuretics, which can lead to muscle cramps, weakness, and cardiac arrhythmias.
- **Hyperkalemia** — A serum potassium level greater than 5.0 mEq/L, which depresses cardiac conduction and can cause life-threatening arrhythmias such as ventricular fibrillation.
- **ABC Priority Framework** — A nursing prioritization model where Airway, Breathing, and Circulation take precedence; a threat to circulation, such as a lethal arrhythmia, is the highest priority.
- **Cardiac Arrhythmia** — An abnormal heart rhythm; in the context of electrolyte imbalances, it represents a critical, life-threatening event requiring immediate intervention.

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