Which one of the following drugs stabilize the cardiac membrane in a patient with hyperkalemia?

ESIC Nursing Officer-7July 2024

Pharmacology

Medium

Appeared in: ESIC Nursing Officer-7July 2024

Explanation

Calcium gluconate directly counteracts the toxic effects of high potassium on the heart muscle's electrical system.
It works by raising the threshold potential of cardiac cells, which reduces excitability and lowers the immediate risk of fatal arrhythmias like ventricular fibrillation.
This is a critical, temporizing measure that protects the heart, buying time for other treatments (like insulin and diuretics) to lower the overall potassium level in the body.

Option A: Sodium bicarbonate does not stabilize the cardiac membrane. Its role is to shift potassium from the bloodstream into the cells, which helps lower the serum potassium level.
Option B: Insulin (given with dextrose) is a primary treatment for lowering serum potassium by shifting it into cells, but it does not directly stabilize the cardiac membrane.
Option D: Digoxin is not a treatment for hyperkalemia. High potassium levels can decrease its therapeutic effect, and co-administration of calcium can potentiate digoxin toxicity, increasing the risk of arrhythmias.

Visual 1: ECG Comparison. An ECG strip showing the classic hyperkalemia changes (tall, peaked T waves; widened QRS complex) next to a strip showing normalization of these changes after IV calcium administration. This visually demonstrates the immediate protective effect on the heart.
Visual 2: Flowchart. A simple flowchart illustrating the emergency management algorithm for severe hyperkalemia: 1. Stabilize the cardiac membrane (IV Calcium), 2. Shift K+ into cells (Insulin/Dextrose, Bicarbonate), 3. Remove K+ from the body (Diuretics, Dialysis).

Clinical Relevance

Nursing practice connection: Use the key finding related to Pharmacological management of hyperkalemia, specifically cardiac membrane stabilization to guide bedside assessment, documentation, and the next nursing action.
Recognizing hyperkalemia on an ECG and anticipating the immediate need for IV calcium is a critical nursing skill to prevent cardiac arrest. This is a true medical emergency.
Nurses must administer IV calcium gluconate slowly and monitor the patient's blood pressure and heart rate, as rapid infusion can cause hypotension and bradycardia.
What if the patient is on digoxin? The nurse must be extremely cautious. While calcium is still needed for life-threatening ECG changes, it must be given more slowly (e.g., infused over 20-30 minutes) to minimize the risk of precipitating digoxin toxicity.

How to Approach the Question

First, identify the key phrase in the question: 'stabilize the cardiac membrane'. This points to a specific mechanism of action, not just any treatment for hyperkalemia.
Next, recall the three main strategies for managing hyperkalemia: 1) Cardiac protection (stabilization), 2) Shifting potassium intracellularly, and 3) Removing potassium from the body.
Evaluate each option against these strategies. Ask yourself, 'What is the primary job of this drug in hyperkalemia?'
Calcium gluconate's unique role is cardiac protection. It doesn't lower the K+ level.
Insulin and sodium bicarbonate both work by shifting potassium. They lower the K+ level but don't directly stabilize the membrane.
Digoxin is not a treatment. This process of categorization will lead you to the correct answer.

Concept Tested & Keywords

Concept Tested: Pharmacological management of hyperkalemia, specifically cardiac membrane stabilization.
Stem keywords: hyperkalemia, stabilize, cardiac membrane, drug
Lead-in keywords: Which one
Negative lead-in flag: false

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