# A client with acute kidney injury and a sharp decrease in urine output has a serum potassium of 6.0 mEq/L. Which order should the nurse administer intravenously right away to prevent cardiac arrest?

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## 문제

A client with acute kidney injury and a sharp decrease in urine output has a serum potassium of 6.0 mEq/L. Which order should the nurse administer intravenously right away to prevent cardiac arrest?

## 보기

1. A potassium-sparing diuretic
2. A vitamin D supplement
3. Total parenteral nutrition (TPN)
4. Dextrose solution mixed with insulin **✔ 정답**
5. A histamine receptor blocker

**정답: 4**

## 해설

Insulin given with dextrose rapidly shifts potassium from the bloodstream into the cells, providing emergency correction of acute hyperkalemia, whereas spironolactone (Aldactone) raises potassium further and is contraindicated.

## 심화 해설

Principles of Emergency Management of Hyperkalemia

For a client with acute kidney injury whose serum potassium is 6.0 mEq/L, the priority intervention is dextrose solution mixed with insulin. This does not remove potassium from the body; rather, it is an emergency measure that rapidly shifts potassium into the cells to prevent life-threatening dysrhythmias and cardiac arrest.

In acute kidney injury, the glomerular filtration rate (GFR) falls abruptly and the kidneys' ability to excrete potassium is markedly reduced. When serum potassium exceeds 6.0 mEq/L, the resting membrane potential of cardiac muscle cells rises, electrical excitability of the heart becomes abnormal, and the risk of lethal dysrhythmias such as ventricular tachycardia, ventricular fibrillation, and asystole increases sharply [1].

Insulin activates the Na⁺-K⁺-ATPase pump located in the cell membrane. When this pump is activated, sodium (Na⁺) moves out of the cell and potassium (K⁺) moves into the cell. With intravenous insulin, cells throughout the body—including skeletal muscle—rapidly take up potassium from the bloodstream, temporarily lowering the serum potassium level within minutes. Dextrose is given along with the insulin to prevent the hypoglycemia that insulin can cause.

The supporting literature describes a client with severe hyperkalemia and a serum potassium as high as 8.7 mmol/L who reported only persistent nausea, with no EKG changes [1]. This illustrates an important clinical lesson: the clinical presentation of hyperkalemia does not always parallel the biochemical severity, and the absence of EKG changes is never reassuring. The laboratory value itself must therefore drive the decision to intervene emergently.

Why the Other Options Are Incorrect

A potassium-sparing diuretic (option 1), such as spironolactone, blocks sodium-potassium exchange in the distal tubule, decreasing potassium excretion and causing retention, so it is contraindicated in hyperkalemia. A vitamin D supplement (option 2) is used to manage secondary hyperparathyroidism in chronic kidney disease and has no direct effect on potassium levels. Total parenteral nutrition (TPN) (option 3) is given for nutritional support and may actually contain potassium depending on the formulation. A histamine receptor blocker (option 5) is used to suppress gastric acid secretion and is unrelated to the emergency management of hyperkalemia.References (research sources)

- [1]Diagnostic Overlap Between Uremia and Severe Hyperkalemia in Chronic Kidney Disease: Emphasizing Laboratory-Guided Urgency Despite Absent EKG Changes.Research articleTahir MH, Tahir F, Tahir MM, Imran A, Asghar S. (2026) · DOI: 10.7759/cureus.107246

## 임상 시나리오

Emergency Management of Life-Threatening HyperkalemiaRationale and nursing care for IV insulin plus dextrose
Insulin activates the Na⁺-K⁺-ATPase pump and drives potassium into the cells, making it the cornerstone of emergency treatment. This is a temporary shifting strategy, not a means of removing potassium from the body.

When serum potassium reaches 6.0 mEq/L or higher, the resting membrane potential of cardiac muscle cells rises and the risk of lethal dysrhythmias such as ventricular fibrillation and asystole climbs sharply, so immediate intervention is required.

10 units of insulin are mixed with 50 mL of 50% dextrose and given intravenously; onset of action is 15–30 minutes and the effect lasts 2–4 hours.

CautionBlood glucose must be checked within 1 hour after administration to monitor for hypoglycemia. Remember that the serum potassium value itself is the decisive basis for emergency treatment, even when no EKG changes are present.

## 핵심 개념

- **Hyperkalemia** — A serum potassium level above 5.5 mEq/L, which can precipitate serious cardiac dysrhythmias.
- **Na⁺-K⁺-ATPase pump** — An active transport protein in the cell membrane that uses ATP to move sodium out of the cell and potassium into the cell.
- **Insulin** — A hormone secreted by the beta cells of the pancreas that activates the Na⁺-K⁺-ATPase pump and shifts potassium into the cells.
- **Acute kidney injury** — An abrupt decline in glomerular filtration rate over hours to days, impairing waste excretion and electrolyte regulation.

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