A 3-year-old child is experiencing distress after having cardiac surgery. Which sign indicates cardiac tamponade?

Heart failure is a serious condition where the heart cannot pump blood effectively enough to meet the body’s needs. It does not mean the heart has stopped, but rather that it is weakened or stiff, leading to symptoms such as shortness of breath, fatigue, and swelling in the legs or abdomen.

Rationale for the correct answer:

B. Digoxin is classified as a cardiac glycoside. It works by increasing the force of myocardial contraction (positive inotrope) and slowing the heart rate by enhancing vagal tone. These effects improve cardiac output and circulation in clients with heart failure.

Rationale for incorrect answers:

A. Angiotensin-converting enzyme (ACE) inhibitor such as enalapril and captopril reduce afterload and preload by blocking the renin–angiotensin–aldosterone system. Digoxin does not act on this system.

C. Diuretic such as furosemide reduce fluid overload by increasing urine output. Digoxin does not promote diuresis.

D. Vasodilator decrease vascular resistance to improve forward blood flow. Digoxin’s primary action is increasing contractility, not dilating blood vessels.

Test-taking strategy:

• If the medication is digoxin/Lanoxin, think cardiac glycoside.
• Associate digoxin with increased contractility + slowed heart rate, not fluid removal or blood pressure control.

Take home points

• Digoxin is a cardiac glycoside.
• It improves cardiac output by strengthening contractions.
• It slows heart rate and improves filling time.
• Digoxin requires close monitoring due to a narrow therapeutic range.

Digoxin is a prescription medication from the cardiac glycoside class that strengthens heart contractions and slows the heart rate. It is mainly used to treat heart failure and certain abnormal heart rhythms (arrhythmias), such as atrial fibrillation.

Rationale for the correct answer:

C. Gastrointestinal symptoms are among the earliest and most common signs of digoxin toxicity, even in pediatric clients. A digoxin level greater than 2 ng/mL is considered toxic. In infants, toxicity may present subtly, but poor feeding, nausea, and vomiting are classic early warning signs that require immediate attention and drug withholding until levels are verified.

Rationale for incorrect answers:

A. Weight gain is more consistent with fluid retention from worsening heart failure, not digoxin toxicity.

B. Digoxin toxicity more commonly causes bradycardia and dysrhythmias, not tachycardia.

D. Seizures can occur in severe or advanced toxicity, but they are not an early or typical finding and would indicate a life-threatening progression rather than initial suspicion.

Test-taking strategy:

• With digoxin questions, think “GI first” for early toxicity.
• Choose early, common signs over late, catastrophic ones unless the question specifically asks for severe toxicity.

Take home points

• Digoxin has a narrow therapeutic index.
• GI symptoms (nausea, vomiting, poor feeding) are early indicators of toxicity.
• Bradycardia and dysrhythmias are also concerning signs.
• Always assess apical pulse and clinical symptoms before administering digoxin.