Question

An elderly client with chronic heart failure (HF) has been treated with digoxin 0.25 mg QD PO, furosemide 80 mg QD PO, potassium chloride 20 mEq QD PO. During morning rounds, the client complains of nausea, no appetite and that the lights are so bright and blurry. The nurse is preparing him for transfer back to the nursing home.

Vital signs: T 98, P 62, RR 18, BP 112/70, apical HR 60, SpO₂ 94% on room air. Digoxin level is 1.5 ng/mL. (20 points each)

• Identify 2 priority nursing assessments for this client, including 1 physical and 1 laboratory findings.
• Based upon the client’s current symptoms of anorexia and visual changes, discuss what the nurse suspects is happening.
• Describe how digoxin’s inotropic and chronotropic actions affect the heart’s function and how the nurse assesses for a therapeutic response.

Answer 1

First question:

Priority nursing assessment:

1. (Physical) Assess the patient's heart rate - digoxin is known to cause bradycardia, cardiac block.
2. (Laboratory) Monitor the patient's serum potassium level. Digoxin prevents K+ from entering from the blood into the cell. Digoxin toxicity can lead to life-threathening hyperkalemia

Second question:

The nurse is suspecting digoxin toxicity:

Explanation

• The therapeutic range of digoxin should be 0.6 - 1.2 ng/l.
• The patient's serum digoxin level is 1.5 ng/l
• The patient's symptoms of anorexia and visual disturbance
• These are early signs of digoxin toxicity.
• Features of digoxin toxicity are as follows:

  • Caridac effects	Non cardiac effects
    Ventricular arrhythmias	Nausea, vomiting, anorexia
    Atrioventricular block	Abdominal pain
    Atrial arrhythmias	Visual disturbances - halos, photophobia, red-green and yellow green vision
    Sinus bradycardia	Confusion, delirium

Third question:

• Digoxin binds to the Na+/K+ ATPase channel on the cardiac myocytes.
• This leads to an inrease in the intracellular sodium level.
• This, inturn, leads to accumulation of Ca+ ion into the cardiac muscle cells (via the Na+ - Ca+ exchange system)
• Increase in the intracellular calcium leads to release of calcium from the sarcoplasmic reticulum.
• This leads to increase in the force of contraction of the cardiac muscle ( increase in the inotropic effect)
• Digoxin increase the vagal influence on the heart. The vagus nerve supplies the parasympathetic influence on the heart.
• This reduces the heart rate ( negative chronotropic effect)

Fourth question:

The therapeutic effect of digoxin can be assessed in the following ways:

• Assess the patient's symptomatic response to drug - reduction in feeling of palpitation, reduce edema.
• Watch for side-effects
• Monitor the serum level of digoxin.
• Assess the patient's understanding of drug therapy and compliance.