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Difficulty: HardReduction of Risk Potential

A client with chronic kidney disease presents to the emergency department reporting profound muscle weakness and palpitations. The continuous cardiac monitor displays tall, peaked T waves and a widened QRS complex. Laboratory results show a serum potassium level of 7.2 mEq/L (7.2 mmol/L). The arterial blood gas (ABG) analysis reveals: pH 7.27, PaCO2 36 mmHg, PaO2 92 mmHg, and HCO3- 16 mEq/L. To immediately reduce the risk of a fatal ventricular dysrhythmia, which prescribed action should the nurse take first?

  1. Administer intravenous calcium gluconate.Answer
  2. B
    Initiate an intravenous infusion of regular insulin and 50% dextrose.
  3. C
    Administer an intravenous bolus of sodium bicarbonate.
  4. D
    Auscultate the apical pulse for one full minute to verify the monitor rhythm.

Answer

The correct action is to administer intravenous calcium gluconate.
The correct action is to administer intravenous calcium gluconate. Severe hyperkalemia (potassium > 7.0 mEq/L) combined with classic ECG changes (peaked T waves, widened QRS complex) indicates impending cardiac arrest. Calcium gluconate acts immediately (within 1 to 3 minutes) to antagonize the cardiotoxicity of potassium. It raises the threshold potential of the myocardial cells, stabilizing the membrane and preventing lethal ventricular dysrhythmias. While it does not lower the serum potassium level, it is the absolute first-line priority to reduce the immediate risk of a fatal physiological complication.

Step-by-Step Solution

1
Analyze the client's clinical presentation, laboratory results, and continuous ECG findings.
The client has severe hyperkalemia (7.2 mEq/L) accompanied by characteristic, life-threatening ECG changes (peaked T waves, widened QRS) and uncompensated metabolic acidosis.
Synthesizing the objective data identifies the most immediate life-threatening condition, which is cardiac toxicity from severe hyperkalemia.
2
Evaluate the physiological mechanism and onset time of the available prescribed interventions.
Calcium gluconate works within minutes to stabilize the myocardium; insulin with dextrose and sodium bicarbonate take 15 to 30 minutes to shift potassium.
Prioritization in an emergency requires selecting the intervention that addresses the most immediate physiological threat (ventricular fibrillation) in the fastest possible time.
3
Select the intervention that provides immediate risk reduction for the fatal complication.
Intravenous calcium gluconate is identified as the absolute highest priority action.
It immediately raises the cardiac threshold potential, protecting the heart from lethal dysrhythmias while other, slower potassium-lowering treatments take effect.

Key Concept

Prioritization of interventions to reduce the risk of life-threatening cardiac complications in severe hyperkalemia.
Estimated Time:1m 30s
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Topics

Reduction of Risk Potential

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