# A nurse is caring for a 68-year-old patient with chronic heart failure who was admitted with acute exacerbation. The patient has been receiving IV furosemide for 3 days and shows signs of improvement. During the morning assessment, which finding would be the MOST important for the nurse to report to the healthcare provider immediately?

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## 문제

A nurse is caring for a 68-year-old patient with chronic heart failure who was admitted with acute exacerbation. The patient has been receiving IV furosemide for 3 days and shows signs of improvement. During the morning assessment, which finding would be the MOST important for the nurse to report to the healthcare provider immediately?

## 보기

1. Blood pressure decreased from 140/90 mmHg to 120/80 mmHg over 24 hours
2. Serum potassium level of 2.8 mEq/L with new onset of muscle weakness **✔ 정답**
3. Daily weight loss of 2 pounds since yesterday with decreased pedal edema
4. Urine output of 150 mL/hour for the past 8 hours with clear yellow urine

**정답: 2**

## 해설

A serum potassium of 2.8 mEq/L with muscle weakness indicates severe hypokalemia, which can cause life-threatening arrhythmias in a heart failure patient on furosemide and requires immediate reporting. Other findings (BP decrease, weight loss, high urine output) are expected responses to diuretic therapy.

## 심화 해설

Clinical Context

This scenario presents a patient with acute decompensated heart failure (ADHF) on intravenous loop diuretic therapy. The core pathophysiological driver of the hospitalization is congestion, driven by sodium and water retention [1]. While loop diuretics like furosemide are first-line agents to relieve this congestion, their use introduces significant risks, particularly profound electrolyte disturbances. The nurse must prioritize findings that indicate a life-threatening complication over expected therapeutic responses.

Analysis of Findings

The critical finding is the serum potassium level of 2.8 mEq/L accompanied by new-onset muscle weakness. This value represents severe hypokalemia. The mechanism is directly linked to the furosemide therapy; by blocking the sodium-potassium-chloride cotransporter in the thick ascending loop of Henle, furosemide massively increases the delivery of sodium to the distal nephron. This overwhelms reabsorption capacity and forces the distal tubules to exchange sodium for potassium at an accelerated rate, leading to excessive urinary potassium loss. The new muscle weakness is a direct clinical manifestation of this electrolyte deficit on neuromuscular function and is a sentinel sign of potential cardiac instability, including life-threatening ventricular arrhythmias.

The other options represent expected and desirable clinical trajectories during effective decongestive therapy. A blood pressure reduction from 140/90 to 120/80 mmHg is an anticipated hemodynamic response to reduced intravascular volume and preload. A daily weight loss of 2 pounds with decreased pedal edema is a direct indicator that the diuretic is successfully achieving its goal of mobilizing excess fluid and relieving congestion [1]. A robust urine output of 150 mL/hour signifies an adequate natriuretic response, which is the intended pharmacological effect and contrasts sharply with the inadequate response seen in diuretic resistance [1].

NCLEX-RN Priority Setting

This question tests the principle of prioritizing care using the ABC (Airway, Breathing, Circulation) framework and the concept of "what is the most immediately life-threatening?" While all options involve assessment findings, only option 2 points directly to a high risk of cardiac dysrhythmia—a "Circulation" crisis. A potassium level below 3.0 mEq/L significantly destabilizes myocardial cell resting membrane potentials, making them hyperpolarized and less excitable, which paradoxically increases the risk for re-entrant arrhythmias. The nurse must recognize that new muscle weakness is not a minor complaint but a critical neurological sign of severe hypokalemia that warrants immediate provider notification for urgent potassium replacement to prevent cardiac arrest.

References (research sources)

- [1]Diuretic resistance in cardiorenal syndrome: mechanisms, monitoring and phenotype-tailored management.Research articleAletras G, Bachlitzanaki M, Stratinaki M, Foukarakis E, Petrakis I, Pantazis Y, Hamilos M, Stylianou K. (2025) · DOI: 10.3389/fcvm.2025.1731305

## 임상 시나리오

Furosemide-Induced HypokalemiaMonitoring and Managing a Critical Electrolyte Imbalance
A serum potassium level of 2.8 mEq/L with new muscle weakness is a critical finding during IV furosemide therapy. This represents severe hypokalemia, which dramatically increases the risk for life-threatening ventricular arrhythmias.

Furosemide blocks the sodium-potassium-chloride cotransporter in the loop of Henle, delivering high sodium loads to the distal tubule. This forces an accelerated exchange of sodium for potassium, leading to excessive urinary potassium wasting.

CautionDo not confuse expected therapeutic responses (weight loss, increased urine output, mild BP reduction) with this dangerous complication. New muscle weakness is a sentinel sign of impending cardiac instability and requires immediate notification of the provider for urgent potassium replacement.

## 핵심 개념

- **Furosemide** — A type of loop diuretic. It promotes diuresis by inhibiting the reabsorption of sodium, potassium, and chloride in the ascending limb of the loop of Henle. It is used to treat fluid overload and edema caused by conditions such as heart failure, liver cirrhosis, and nephrotic syndrome.
- **Hypokalemia** — Serum potassium level is lower than the normal range (3.5-5.0 mEq/L). Causes may include diuretic use, vomiting, or diarrhea. It can lead to muscle weakness, cramps, and arrhythmias (especially T-wave flattening and U-wave appearance).
- **Chronic Heart Failure** — A chronic condition where the heart's pumping function progressively declines, failing to supply enough blood to meet the metabolic demands of the body's tissues. It presents as left-sided heart failure, right-sided heart failure, or biventricular heart failure.
- **Loop Diuretic** — A class of drugs that acts on the loop of Henle in the kidney nephron to produce a potent diuretic effect. Includes furosemide, bumetanide, and torsemide. Promotes potassium excretion.
- **Ventricular Arrhythmia** — Abnormal heart rhythms originating in the ventricles. This includes premature ventricular contractions (PVC), ventricular tachycardia (VT), and ventricular fibrillation (VF). Hypokalemia is an important risk factor that can trigger or worsen these conditions.

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