Medical Surgical Potassium K+ #18

Question

The nurse notes that a client has a serum potassium level of 3.2 mEq/L. Which finding should the nurse expect on the client’s electrocardiogram (ECG)?

Answers

  1. U waves
    • Rationale:

      This answer is correct because hypokalemia is a potentially life-threatening electrolyte imbalance that can cause inverted T waves, ST segment depression, and prominent U waves.

  2. Absent P waves
    • Rationale:

      This answer is not correct because an increase in the P wave amplitude may occur for the client who experiences hypokalemia; therefore, an absence of the P wave is not anticipated for this client. Hypokalemia increases the client’s risk for arrhythmias which is potentially life-threatening; therefore, continuous cardiopulmonary monitoring is essential.

  3. Elevated T waves
    • Rationale:

      This answer is not correct because flattening or inversion of T waves is expected for the client who experiences hypokalemia; therefore, elevated T waves is not anticipated for this client. Hypokalemia increases the client’s risk for arrhythmias which is potentially life-threatening; therefore, continuous cardiopulmonary monitoring is essential.

  4. Elevated ST segment
    • Rationale:

      This answer is not correct because mild depression of the ST segment is expected for the client who experiences hypokalemia; therefore, an elevated ST segment is not anticipated for this client.

Overview

Potassium is a mineral and electrolyte that plays an important role in both nerve conduction and muscle contraction. Hypokalemia increases the client’s risk for arrhythmias which is potentially life-threatening; therefore, continuous cardiopulmonary monitoring is essential.

Explanation

Learning Outcomes

The normal range for serum potassium within the body is 3.5 to 5 mEq/L. When the client’s serum potassium level is less than 3.5 mEq/L, hypokalemia is diagnosed. Hypokalemia increases the client’s risk for arrhythmias which is potentially life-threatening; therefore, continuous cardiopulmonary monitoring is essential. ECG changes that can occur with mild hypokalemia include flattening and inversion of T waves. Clients with severe hypokalemia often experience Q-T interval prolongation, visible U wave, and mild ST depression. Severe hypokalemia can also result in arrhythmias such as Torsades de pointes and ventricular tachycardia.

Test Taking Tip

Consider the impact of hypokalemia on the conduction system of the heart to answer this question correctly.

Video Rationale