A nurse caring an assigned client in ICU. Nurse noticing on the cardiac monitor that prominent U wave, ST segment depression, this finding is usually seen in?

1. A

   Hyperkalemia

2. B

   Hypokalemia

3. C

   Hypocalcemia

4. D

   Hypercalcemia

Appeared in: NIMHANS Nursing Officer - 2019

Explanation

• Hypokalemia, a low serum potassium level, characteristically alters the repolarization phase of the cardiac cycle.
• This alteration manifests on the ECG as ST-segment depression, flattening or inversion of the T wave, and the appearance of a prominent U wave.
• The question's description of a prominent U wave and ST segment depression directly matches the classic ECG signs of hypokalemia.

Why Other Options Were Wrong

• Option A: Hyperkalemia (high potassium) presents with different ECG changes, primarily affecting depolarization and rapid repolarization.
• Option C: Hypocalcemia (low calcium) primarily affects the duration of the action potential's plateau phase, not repolarization in a way that creates U waves.
• Option D: Hypercalcemia (high calcium) shortens the action potential's plateau phase.

Related Visual

Clinical Relevance

• Nursing practice connection: Prioritize focused assessment, early escalation, and real-time monitoring when managing ECG Interpretation in Electrolyte Imbalances in acute care settings.
• Recognizing ECG changes related to electrolyte imbalances is a critical nursing skill in the ICU, as these changes can be the first sign of a life-threatening condition.
• Prompt identification and reporting allow for timely intervention, such as potassium replacement, which can prevent cardiac arrest.
• What if? If the patient's ECG showed tall, peaked T-waves instead, the nurse should suspect Hyperkalemia and immediately notify the provider, anticipating orders for interventions like insulin/dextrose, calcium gluconate, or dialysis to lower potassium levels.

How to Approach the Question

• First, identify the key clinical findings presented in the question stem: 'prominent U wave' and 'ST segment depression'.
• Second, recognize that these are specific ECG abnormalities.
• Third, access your knowledge base on how different electrolyte imbalances affect the ECG.
• Fourth, systematically compare the given findings to the known patterns for each option: Hyperkalemia, Hypokalemia, Hypocalcemia, and Hypercalcemia.
• Finally, select the option (Hypokalemia) whose characteristic ECG changes perfectly match the findings described in the question.

Concept Tested & Keywords

• Concept Tested: ECG Interpretation in Electrolyte Imbalances
• Stem keywords: cardiac monitor, prominent U wave, ST segment depression
• Lead-in keywords: usually seen in
• Clinical cues: Patient is in the ICU, indicating a higher risk for electrolyte disturbances.

Question ID

Q9c8dgyY20ng4-1dzutlEg

Copy ID

Reference Book

E6 Nursing Fundamentals Potter Perry 12e Part 5 p. 53-55

E6 Medicine Harrison 22e Part 1 p. 1916-1918