A patient admitted in ICU. In the morning his blood report received from laboratory and potassium level is 6.5 mEq/L. Which of the following ECG finding can be associated with Hyperkalemia?

Appeared in: NORCET 3 - 2022 (Shift-2)

Explanation

A serum potassium level of 6.5 mEq/L is defined as moderate to severe hyperkalemia, a potentially life-threatening condition.
The earliest and most characteristic ECG change associated with hyperkalemia is the appearance of tall, narrow, peaked T waves, often described as 'tented' T waves.
This change reflects altered ventricular repolarization due to the high extracellular potassium concentration.
As hyperkalemia worsens, other changes can occur, including a prolonged PR interval, widening of the QRS complex, and eventually a 'sine wave' pattern preceding cardiac arrest.

Option A: A prominent U wave is a hallmark ECG finding of hypokalemia (low potassium), the opposite of the patient's condition.
Option B: ST segment depression is characteristic of hypokalemia and myocardial ischemia, not hyperkalemia.
Option C: T wave inversion or flattening is a sign of hypokalemia or ischemia. Hyperkalemia causes the T waves to become taller and more peaked.

Clinical Relevance

Nursing practice connection: Prioritize focused assessment, early escalation, and real-time monitoring when managing ECG interpretation in electrolyte imbalances, specifically hyperkalemia in acute care settings.
Recognizing ECG changes of hyperkalemia is a critical nursing skill, as it is a medical emergency that can lead to fatal cardiac arrhythmias if not treated promptly.
Nurses in critical care settings must be prepared to act quickly, including notifying the provider, initiating continuous cardiac monitoring, and preparing emergency medications like IV calcium gluconate, insulin, and dextrose.
Patient safety is paramount. A common cause of falsely elevated potassium (pseudohyperkalemia) is hemolysis of the blood sample. A nurse might anticipate an order to redraw the labs to confirm the value while still preparing for the worst-case scenario.

How to Approach the Question

First, analyze the clinical data provided in the question. The key piece of information is the lab value: potassium 6.5 mEq/L.
Second, classify this lab value. A normal potassium range is 3.5-5.2 mEq/L, so 6.5 mEq/L is high, indicating hyperkalemia.
Third, access your knowledge base to recall the specific ECG manifestations of hyperkalemia.
Fourth, evaluate each of the given options. Compare them to the known ECG patterns for hyperkalemia.
Eliminate the options that are associated with the opposite condition (hypokalemia) or other conditions (e.g., ischemia). Prominent U waves, ST depression, and inverted T waves are all classic signs of hypokalemia.
Finally, select the option that is the earliest and most characteristic sign of hyperkalemia, which is the tall, peaked T wave.

Concept Tested & Keywords

Concept Tested: ECG interpretation in electrolyte imbalances, specifically hyperkalemia.
Stem keywords: ICU, potassium level, 6.5 mEq/L, Hyperkalemia, ECG finding
Lead-in keywords: Which of the following
Clinical cues: Potassium level of 6.5 mEq/L is a critical value indicating severe hyperkalemia, which is a medical emergency.
Negative lead-in flag: false

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E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 541-543

E6 Medicine Harrison 22e Part 1 pp. 1915-1917, 1911-1913

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