A teenage client with heart failure is prescribed digoxin (Lanoxin) and asks the nurse, “What’s the drug supposed to do?” The nurse teaches the teenager based on the understanding that this drug belongs to which classification?

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.

Cardiac surgery is any surgical procedure performed on the heart or its major blood vessels to correct structural problems, restore blood flow, or improve heart function. It is often used to treat conditions like coronary artery disease, heart valve disorders, congenital heart defects, or advanced heart failure.

Rationale for the correct answer:

C. Weak peripheral pulses: Cardiac output depends on heart rate and stroke volume. When cardiac output decreases, less blood is ejected into the systemic circulation, resulting in diminished pulse strength, especially in the extremities. Weak pulses are an early and reliable bedside indicator of poor perfusion, particularly important in post–cardiac surgery pediatric patients.

Rationale for incorrect answers:

A. Hypertension: This is not typical of decreased cardiac output. Reduced cardiac output more commonly leads to hypotension, not elevated blood pressure.

B. Increased urine output: Adequate or increased urine output indicates good renal perfusion, which suggests adequate cardiac output, not decreased output.

D. Capillary refill less than 2 seconds: A refill time under 2 seconds indicates normal peripheral perfusion. Decreased cardiac output is associated with delayed capillary refill (>2–3 seconds).

Test-taking strategy:

• Think “poor pump = poor perfusion.”
• Signs of decreased cardiac output include weak pulses, delayed capillary refill, low urine output, hypotension, and altered mental status.

Take home points

• Weak peripheral pulses = decreased cardiac output.
• Good urine output and fast capillary refill indicate adequate perfusion.
• After cardiac surgery, pulse quality is a key priority assessment.