# A nurse is assessing a 58-year-old patient with sepsis and hypotension, who is suspected of having acute kidney injury (AKI). Which assessment finding would be the MOST significant indicator of severe AKI requiring immediate intervention?

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## 문제

A nurse is assessing a 58-year-old patient with sepsis and hypotension, who is suspected of having acute kidney injury (AKI). Which assessment finding would be the MOST significant indicator of severe AKI requiring immediate intervention?

## 보기

1. Serum creatinine increased from 1.0 mg/dL to 3.0 mg/dL over 48 hours
2. Urine output decreased to 200 mL over the past 24 hours
3. Blood urea nitrogen (BUN) level elevated to 60 mg/dL
4. Serum potassium level of 7.2 mEq/L with peaked T waves on ECG **✔ 정답**

**정답: 4**

## 해설

Hyperkalemia with ECG changes (peaked T waves) is a life-threatening emergency in AKI requiring immediate intervention to prevent fatal arrhythmias. Other findings (creatinine rise, oliguria, elevated BUN) are severe but less urgent.

## 심화 해설

Clinical Reasoning and Prioritization

In a patient with sepsis and suspected acute kidney injury (AKI), the nurse must rapidly identify the finding that indicates a life-threatening complication requiring immediate intervention. While all options reflect worsening renal function, the priority is determined by the risk of imminent cardiac arrest.

Analysis of the Options

Option 1 describes a rise in serum creatinine from 1.0 mg/dL to 3.0 mg/dL over 48 hours. This meets the KDIGO criteria for stage 2 AKI and indicates significant parenchymal damage [1]. However, creatinine elevation itself is a marker of decreased glomerular filtration and is not directly cardiotoxic. It signals the need for close monitoring and management of the underlying cause but does not, in isolation, demand an instantaneous, emergent response like the correct option.

Option 2 identifies a urine output of 200 mL over 24 hours, which is severe oliguria (less than 0.5 mL/kg/hr). This is a classic criterion for stage 3 AKI and is a strong predictor of the eventual need for renal replacement therapy (RRT) [1]. Oliguria reflects a critical drop in the kidney's excretory function, leading to fluid overload and accumulation of waste products. While this is a serious finding that necessitates urgent nephrology consultation and preparation for potential RRT, the immediate threat to life is not as instantaneous as a severe electrolyte disturbance affecting cardiac conduction.

Option 3 presents an elevated blood urea nitrogen (BUN) level of 60 mg/dL. This azotemia confirms that the kidneys are failing to excrete nitrogenous wastes. Uremia can cause platelet dysfunction, encephalopathy, and pericarditis, but these are subacute complications. A BUN of 60 mg/dL is a significant finding that supports the diagnosis of AKI and contributes to the clinical picture of uremia, yet it does not represent an immediate, life-threatening emergency requiring the most rapid intervention.

Option 4 identifies a serum potassium level of 7.2 mEq/L with peaked T waves on the electrocardiogram (ECG). This is the most significant finding. Severe hyperkalemia is a direct consequence of the kidney's inability to excrete potassium in AKI. A potassium level above 6.5 mEq/L, especially with ECG changes, signifies a critical state where the cardiac myocyte resting membrane potential is dangerously altered, predisposing the heart to ventricular fibrillation or asystole . The ECG manifestation of peaked T waves is a classic and ominous sign of cardiotoxicity. This finding demands immediate intervention, such as administration of intravenous calcium gluconate to stabilize the cardiac membrane, followed by therapies to shift potassium intracellularly (e.g., insulin and glucose, beta-agonists) and remove it from the body (e.g., diuretics, dialysis).

Pathophysiological Link and the BRASH Syndrome Concept

The urgency of treating severe hyperkalemia in the context of AKI is further underscored by the concept of BRASH syndrome (Bradycardia, Renal failure, Atrioventricular nodal blockade, Shock, and Hyperkalemia). This syndrome illustrates a vicious cycle where renal failure leads to hyperkalemia, which synergistically with AV nodal blocking agents (or intrinsic conduction disease) causes profound bradycardia and shock, which in turn worsens renal perfusion and hyperkalemia [3, 4]. The presence of peaked T waves on the ECG is the critical warning sign that this cycle is spiraling toward a catastrophic cardiac event. The nurse must recognize that a potassium of 7.2 mEq/L with ECG changes is not just a laboratory abnormality; it is the most immediate threat to the patient's life, requiring emergent action before the rhythm deteriorates further.References (research sources)

- [1]Acute Kidney Injury in the Emergency Department: Key Predictors for Early Renal Replacement Therapy.Research articleAkdoğanlar Aİ, Satar S, Acehan S, Gülen M, Onan E, Kuleci S, Sevdimbaş S, Kuş C. (2026) · DOI: 10.5152/eurasianjmed.2026.251272

## 임상 시나리오

Managing Life-Threatening Hyperkalemia in AKIPrioritizing Cardiac Risk Over Renal Markers
In AKI, a serum potassium level of 7.2 mEq/L with peaked T waves on ECG is a pre-arrest emergency. This indicates severe cardiotoxicity from impaired renal excretion, requiring immediate intervention before dialysis or other AKI management steps.

The immediate priority is to stabilize the cardiac membrane. Administer IV calcium gluconate or calcium chloride first to antagonize the myocardial effects of potassium. This does not lower serum potassium but protects the heart.

Subsequent steps involve shifting potassium intracellularly with IV regular insulin and dextrose, and often a beta-2 agonist like albuterol. Definitive removal is achieved via renal replacement therapy or potassium binders.

CautionNever prioritize rising creatinine or oliguria over ECG changes from hyperkalemia. A potassium >6.5 mEq/L with ECG changes is a code-blue risk; treatment must begin within minutes.

## 핵심 개념

- **Hyperkalemia** — A serum potassium level exceeding 5.0 mEq/L; levels above 6.5 mEq/L are a medical emergency due to the risk of life-threatening cardiac arrhythmias.
- **Peaked T waves** — An early electrocardiographic manifestation of hyperkalemia, characterized by tall, narrow, and pointed T waves, often best seen in the precordial leads.
- **KDIGO Criteria** — Kidney Disease: Improving Global Outcomes clinical practice guidelines used to define and stage acute kidney injury based on serum creatinine and urine output changes.
- **Oliguria** — Urine output of less than 400 mL per day in adults, a common feature of acute kidney injury.
- **Cardiac membrane stabilization** — An emergency treatment for severe hyperkalemia using intravenous calcium gluconate or calcium chloride to antagonize the cardiac effects of potassium and prevent lethal arrhythmias.

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