NCLEX Practice Exam for Pediatric Nursing: Cardiovascular Disorders

EXPLANATION

✔Correct answer:

Addressing streptococcal throat infections promptly with antibiotics. Rheumatic fever is a serious inflammatory disease that can develop as a complication of untreated or inadequately treated streptococcal throat infections (streptococcal pharyngitis or strep throat) caused by group A Streptococcus bacteria. Prompt and effective treatment of strep throat with appropriate antibiotics, such as penicillin, is crucial in preventing the initial onset of rheumatic fever. This helps eradicate the streptococcal bacteria, preventing the immune response that can lead to rheumatic fever.

Treating a streptococcal infection with antibiotics is like putting out a small fire before it spreads and causes more damage. By addressing the infection promptly, you prevent it from escalating into a more severe condition like rheumatic fever.

Rheumatic fever occurs when the immune system responds to a streptococcal infection with an exaggerated inflammatory response that can affect the heart, joints, skin, and brain. This autoimmune reaction can result in permanent damage to the heart valves (rheumatic heart disease). By treating strep throat with antibiotics, the bacterial infection is eliminated, thereby preventing the abnormal immune response that leads to rheumatic fever.

✘Incorrect answer options:

Administering corticosteroids to decrease inflammation. While corticosteroids may be used to manage inflammation in rheumatic fever, they are not a preventive measure for the initial development of the condition.

Taking antibiotics prophylactically before any dental procedures. This measure is used to prevent bacterial endocarditis in individuals with certain heart conditions, not to prevent the initial onset of rheumatic fever.

Prescribing penicillin specifically for rheumatic fever treatment. Penicillin can be used in the treatment and secondary prevention of rheumatic fever, but it is not specific to the initial prevention of the condition. The primary prevention strategy focuses on treating strep throat promptly.

EXPLANATION

✔Correct answer:

Jatene Procedure. The Jatene procedure, also known as the arterial switch operation, is the surgery Nurse Thompson is referring to. This procedure is performed to correct Transposition of the Great Arteries (TGA), a congenital heart defect where the positions of the main arteries (the aorta and the pulmonary artery) are switched. In TGA, the aorta arises from the right ventricle, and the pulmonary artery arises from the left ventricle, resulting in the circulation of deoxygenated blood through the body and oxygenated blood through the lungs, which is not sustainable for life.

The Jatene procedure involves switching the aorta and pulmonary artery to their correct anatomical positions. This procedure redirects the blood flow so that the left ventricle pumps oxygenated blood to the body and the right ventricle pumps deoxygenated blood to the lungs, correcting the circulation.

Imagine two pipes that have been connected incorrectly, causing clean water to circulate in a closed loop and dirty water to circulate in another. The Jatene procedure is like a plumber switching the pipes to ensure clean water is sent to the house and dirty water to the treatment plant.

In TGA, the misplacement of the great arteries leads to the ineffective delivery of oxygenated blood to the systemic circulation. The Jatene procedure corrects this by anatomically repositioning the great arteries to their respective ventricles, ensuring that oxygenated blood from the left ventricle is delivered to the body, and deoxygenated blood from the right ventricle is sent to the lungs for oxygenation.

✘Incorrect answer options:

Pulmonary Artery Banding. This procedure is used to reduce pulmonary blood flow and pressure in cases of left-to-right shunt defects, such as ventricular septal defect (VSD), but it does not correct TGA.

Rashkind Procedure. Also known as balloon atrial septostomy, this procedure is used as a palliative measure to improve oxygenation by creating or enlarging an atrial septal defect (ASD) to allow mixing of oxygenated and deoxygenated blood. However, it is not the definitive corrective surgery for TGA.

Rastelli Procedure. This procedure is used to correct certain types of complex congenital heart defects, such as double outlet right ventricle with pulmonary stenosis. It involves creating a conduit to redirect blood flow but is not the primary corrective surgery for TGA.

EXPLANATION

✔Correct answer:

Utilizing nipples that require minimal effort for the infant to suck. For an infant with heart failure, feeding can be particularly challenging due to the increased energy expenditure and potential for fatigue. Using nipples that require minimal effort for the infant to suck helps to reduce the energy required for feeding, making it easier for the infant to obtain adequate nutrition without becoming overly tired. This strategy helps to ensure the infant can feed effectively and gain necessary nutrients for growth and health.

Think of trying to drink through a very narrow straw versus a wider one. The narrower straw takes more effort and energy, while the wider one makes it easier to drink with less effort. Similarly, using a nipple that requires minimal effort makes feeding less strenuous for the infant.

Infants with heart failure often experience difficulty feeding due to the increased workload on their heart and the associated fatigue. By minimizing the effort required to suck, the infant can feed more efficiently and comfortably, leading to better intake of nutrition. This helps to support growth and prevent malnutrition, which is critical in managing heart failure.

✘Incorrect answer options:

Giving substantial feedings at intervals of every 4 hours. Large, infrequent feedings can be overwhelming and tiring for an infant with heart failure. Smaller, more frequent feedings are generally recommended to ensure adequate nutrition without causing excessive fatigue.

Giving formula enriched with high levels of sodium and calories. While higher calorie formulas can be beneficial, increasing sodium levels is not recommended as it can lead to fluid retention and worsen heart failure. Nutritional modifications should focus on providing adequate calories without excess sodium.

Letting the infant feed for a duration of at least one hour. Prolonged feeding sessions can lead to fatigue and may not be effective for infants with heart failure. Shorter, more frequent feedings are typically more manageable and less tiring for the infant.

EXPLANATION

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Ventricular septal defect, overriding aorta, pulmonic stenosis (PS), and right ventricular hypertrophy. Tetralogy of Fallot is a congenital heart defect that involves four key anatomical abnormalities. Nurse Walters should explain these four defects to the Smith Family:

1. Ventricular Septal Defect (VSD): A hole between the right and left ventricles that allows oxygen-poor blood to mix with oxygen-rich blood.
2. Overriding Aorta: The aorta is positioned directly above the ventricular septal defect, receiving blood from both the right and left ventricles.
3. Pulmonic Stenosis (PS): Narrowing of the pulmonary valve or artery, which reduces blood flow to the lungs.
4. Right Ventricular Hypertrophy: Thickening of the muscular walls of the right ventricle due to the increased workload caused by the other defects.

These defects work together to decrease the amount of oxygen-rich blood that is delivered to the body, leading to symptoms like cyanosis (a bluish tint to the skin).

Imagine a plumbing system where there are several issues: a hole in one of the main pipes, a valve that doesn’t fully open, a pipe that is connected incorrectly, and a pump that has to work extra hard because of all these problems. Each of these issues represents one of the defects in tetralogy of Fallot.

The combination of these defects results in reduced blood flow to the lungs and mixing of oxygenated and deoxygenated blood. This causes lower oxygen levels in the blood that circulates throughout the body, leading to the characteristic symptoms of cyanosis and episodes of "tet spells" (sudden drops in oxygenation).

✘Incorrect answer options:

Aorta exits from the right ventricle, pulmonary artery exits from the left ventricle, and two noncommunicating circulations. This describes transposition of the great arteries, not tetralogy of Fallot.

Coarctation of aorta, aortic valve stenosis, mitral valve stenosis, and patent ductus arteriosus. These are different congenital heart defects and do not collectively describe tetralogy of Fallot.

Tricuspid valve atresia, atrial septal defect, ventricular septal defect, and hypoplastic right ventricle. These defects describe tricuspid atresia, not tetralogy of Fallot.

EXPLANATION

✔Correct answer:

The sinoatrial (SA) node functions as the heart's natural pacemaker. The sinoatrial (SA) node is located in the right atrium and is responsible for initiating the electrical impulses that set the rate and rhythm of the heart, thus functioning as the heart's natural pacemaker. It generates action potentials that spread through the atria, causing them to contract and push blood into the ventricles.

Think of the SA node as the conductor of an orchestra, setting the tempo and ensuring all the musicians (heart chambers) play in sync to produce a harmonious performance (heartbeats).

The SA node spontaneously generates electrical impulses at regular intervals, which are then transmitted through the atria to the atrioventricular (AV) node, and subsequently through the rest of the conduction system. This sequence ensures coordinated contraction of the heart muscles, allowing efficient pumping of blood.

✘Incorrect answer options:

The AV node swiftly transmits action potentials. This statement is incorrect. The AV node actually slows down the transmission of action potentials to ensure that the atria have enough time to contract and empty their blood into the ventricles before the ventricles contract.

The atrioventricular bundle conducts action potentials at a slow pace. This statement is incorrect. The atrioventricular bundle (Bundle of His) conducts action potentials rapidly to the right and left bundle branches, which then transmit the impulses to the Purkinje fibers, leading to a coordinated contraction of the ventricles.

The SA node is positioned on the upper wall of the left atrium. This statement is incorrect. The SA node is located in the right atrium, near the opening of the superior vena cava.

EXPLANATION

✔Correct answer:

The likelihood of aneurysm formation. One of the most serious complications of Kawasaki disease is the formation of coronary artery aneurysms. Kawasaki disease causes inflammation of the blood vessels throughout the body, including the coronary arteries, which supply blood to the heart. This inflammation can lead to weakening and bulging of the artery walls, resulting in aneurysms. These aneurysms can increase the risk of blood clots, heart attacks, and other cardiovascular complications, even after the acute phase of the disease has resolved.

Imagine a garden hose that has sections where the material becomes thin and balloons out due to high pressure. These weak spots are similar to aneurysms in blood vessels, where the vessel wall has been weakened and bulges out, posing a risk for rupture or blockages.

Kawasaki disease predominantly affects children and involves inflammation of the medium-sized arteries, particularly the coronary arteries. The condition can cause lasting damage to the coronary arteries if not treated promptly and effectively. Regular follow-up with echocardiograms and other imaging studies is crucial to monitor the coronary arteries and detect any aneurysm formation early.

✘Incorrect answer options:

The potential development of meningitis. Meningitis is an infection of the protective membranes covering the brain and spinal cord. While Kawasaki disease involves inflammation, it is not typically associated with meningitis.

The onset of mitral valve disease. Mitral valve disease involves the heart's mitral valve and is not a common complication of Kawasaki disease. The primary concern with Kawasaki disease is the coronary arteries.

The risk of sepsis. Sepsis is a severe infection that spreads throughout the body. Kawasaki disease itself is not an infectious process and does not typically lead to sepsis. The primary concern is inflammation of the blood vessels and the risk of aneurysm formation.

EXPLANATION

✔Correct answer:

Significantly slow heart rate or extreme bradycardia. One of the key indicators of digoxin toxicity is bradycardia, or an abnormally slow heart rate. Digoxin works by increasing the force of cardiac contractions and slowing the heart rate to improve cardiac output in heart failure patients. However, excessive levels of digoxin can cause significant bradycardia, leading to symptoms such as dizziness, fatigue, and fainting. Monitoring heart rate is crucial in patients receiving digoxin therapy to detect signs of toxicity early.

Imagine using a brake on a bicycle to control speed. Using it too much can slow down the bike excessively or even stop it. Similarly, too much digoxin can slow the heart too much, causing bradycardia.

Digoxin has a narrow therapeutic index, meaning the range between a therapeutic dose and a toxic dose is very small. Toxicity can lead to various cardiac arrhythmias, with bradycardia being one of the most common. Continuous monitoring of heart rate and regular blood tests to check digoxin levels can help prevent toxicity.

✘Incorrect answer options:

Difficulty breathing or respiratory distress. While heart failure can cause respiratory distress, it is not a primary indicator of digoxin toxicity. Respiratory symptoms would prompt evaluation of heart failure status rather than digoxin levels.

Difficulty with bowel movements or constipation. Constipation is not a typical symptom of digoxin toxicity. While gastrointestinal symptoms such as nausea, vomiting, and diarrhea can occur, constipation is not a key indicator.

Pain in the head or headache. Headaches are not a common sign of digoxin toxicity. Symptoms more indicative of toxicity include visual disturbances (such as seeing halos around lights), confusion, nausea, and bradycardia.

EXPLANATION

✔Correct answer:

Tetralogy of Fallot. Tetralogy of Fallot is a congenital heart defect that typically results in cyanosis due to the mixing of deoxygenated blood with oxygenated blood in the systemic circulation. This condition consists of four anatomical abnormalities:

1. Ventricular Septal Defect (VSD): A hole between the right and left ventricles allows deoxygenated blood from the right ventricle to mix with oxygenated blood in the left ventricle.
2. Pulmonary Stenosis: Narrowing of the pulmonary valve or artery reduces blood flow to the lungs, increasing pressure in the right ventricle and exacerbating the mixing of blood.
3. Overriding Aorta: The aorta is positioned directly above the ventricular septal defect, receiving blood from both the right and left ventricles.
4. Right Ventricular Hypertrophy: Thickening of the right ventricular muscle due to increased workload from the pulmonary stenosis.

These defects work together to reduce the amount of oxygenated blood delivered to the body, leading to cyanosis, a bluish tint to the skin, lips, and nails due to low oxygen levels.

Imagine a plumbing system with a mix of clean and dirty water flowing through a single pipe due to leaks and misalignments. Similarly, in Tetralogy of Fallot, deoxygenated and oxygenated blood mix due to structural defects in the heart, leading to reduced oxygen levels in the bloodstream.

In Tetralogy of Fallot, the mixing of deoxygenated and oxygenated blood results in hypoxemia and cyanosis. Surgical correction is typically required to repair the defects and improve oxygenation.

✘Incorrect answer options:

Narrowing of the aorta. This condition, known as coarctation of the aorta, involves a narrowing that obstructs blood flow but does not typically cause cyanosis due to deoxygenated blood mixing with oxygenated blood.

Narrowing of the aortic valve. Aortic stenosis is the narrowing of the aortic valve, which impedes blood flow from the left ventricle to the aorta. It does not usually result in cyanosis due to the mixing of blood.

Persistent opening between the aorta and the pulmonary artery. This condition is known as patent ductus arteriosus (PDA). While PDA can cause abnormal circulation and lead to heart failure if severe, it typically does not cause cyanosis due to the mixing of deoxygenated blood with oxygenated blood.

EXPLANATION

✔Correct answer:

Organizing care activities to ensure the infant has periods of undisturbed rest. For a child with heart disease, reducing cardiac demands is crucial to minimize the workload on the heart. Prioritizing periods of undisturbed rest helps achieve this goal by preventing excessive energy expenditure and allowing the heart to function more efficiently. Ensuring the infant has adequate rest periods reduces the physiological stress on the heart, thereby helping to manage symptoms and promote better overall health.

Think of the heart as a hardworking engine. Just as an engine needs downtime to cool off and prevent overheating, the infant's heart needs rest periods to reduce stress and function optimally.

Rest periods are essential because they decrease metabolic demands on the body, thus reducing the workload on the heart. This helps prevent fatigue and cardiac decompensation in children with heart disease. By organizing care activities around these rest periods, Nurse Thompson can help maintain the infant's cardiac stability and promote recovery.

✘Incorrect answer options:

Crafting and executing a predictable and steady care routine. While a predictable routine can provide a sense of security and reduce anxiety, it is not as directly effective in reducing cardiac workload as ensuring undisturbed rest periods.

Extending the duration of feedings for the infant. Prolonging feedings can actually increase energy expenditure and fatigue the infant, potentially increasing cardiac workload rather than reducing it.

Giving in to the infant's preferences to prevent any form of conflict. While minimizing stress is important, it should not come at the expense of necessary care interventions. This option does not address the need to manage and reduce cardiac workload effectively.

EXPLANATION

✔Correct answer:

SA node — AV node — Atrioventricular bundle — Right and Left bundle branches — Purkinje fibers. The correct sequence of the heart's conduction system is as follows:

1. SA node (Sinoatrial node): The action potential originates here. The SA node is located in the right atrium and serves as the heart's natural pacemaker.
2. AV node (Atrioventricular node): The impulse then travels to the AV node, which is located at the junction of the atria and ventricles. The AV node slows the electrical signal before it moves to the ventricles.
3. Atrioventricular bundle (Bundle of His): From the AV node, the impulse travels to the atrioventricular bundle, which is a pathway that conducts the signal to the ventricles.
4. Right and Left bundle branches: The signal then travels down the right and left bundle branches, which run along the interventricular septum.
5. Purkinje fibers: Finally, the impulse reaches the Purkinje fibers, which distribute the electrical signal throughout the ventricles, causing them to contract.

Think of the heart's conduction system like a relay race. The SA node is the first runner, passing the baton to the AV node. The AV node hands it off to the atrioventricular bundle (Bundle of His), which splits into two runners (right and left bundle branches). Finally, the baton is handed to the Purkinje fibers, which deliver the signal to the finish line, causing the ventricles to contract.

The heart's conduction system ensures that the heart beats in a coordinated manner, allowing efficient pumping of blood. The action potential's pathway through these structures coordinates the contraction of the atria and ventricles, maintaining proper cardiac rhythm and function.

✘Incorrect answer options:

Purkinje fibers — SA node — Right and Left bundle branches — Atrioventricular bundle — AV node. This sequence incorrectly places the Purkinje fibers at the beginning, and it does not follow the correct anatomical order of the conduction system.

Atrioventricular bundle — SA node — Purkinje fibers — Right and Left bundle branches — AV node. This sequence incorrectly places the atrioventricular bundle at the start and does not follow the proper flow of electrical impulses through the heart.

Purkinje fibers — SA node — Atrioventricular bundle — Right and Left bundle branches — AV node. This sequence incorrectly places the Purkinje fibers at the start and does not follow the correct anatomical order of the conduction system.

EXPLANATION

✔Correct answer:

Maintaining a normal weight for his age. Maintaining a normal weight for his age indicates that Justin is likely adhering to his therapeutic regimen for heart failure. Effective management of heart failure often includes dietary modifications to control fluid retention and prevent malnutrition. Regular monitoring of weight is crucial as it helps in assessing fluid balance and nutritional status. If Justin's weight is within the normal range for his age, it suggests that he is following dietary recommendations, adhering to fluid restrictions, and taking his medications as prescribed, all of which are vital components of heart failure management.

Think of managing heart failure like maintaining a balanced checkbook. Keeping track of expenses (diet, medication) ensures that the balance (weight) stays within the desired range, indicating good management of resources.

In heart failure, the heart's ability to pump blood is compromised, leading to fluid buildup and potential weight gain due to fluid retention. Maintaining a stable weight within the normal range for his age suggests effective control of fluid retention and good nutritional status, which are critical in managing heart failure.

✘Incorrect answer options:

A pulse rate consistently below 50 beats per minute. A pulse rate below 50 beats per minute is abnormally low for a child and could indicate bradycardia, which is not a sign of effective heart failure management. It may suggest overmedication with certain heart medications or other complications.

Taking an antibiotic daily. Taking an antibiotic daily is not typically part of the therapeutic regimen for heart failure. Antibiotics are used to treat bacterial infections, not to manage heart failure.

An increase in his red blood cell (RBC) count. An increased RBC count is not a standard indicator of adherence to a heart failure regimen. It could be related to other conditions such as polycythemia or hypoxia but does not reflect the management of heart failure.

EXPLANATION

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Weak or absent femoral pulses. Coarctation of the aorta (CoA) is characterized by a narrowing of the aorta, which obstructs blood flow from the heart to the lower part of the body. This obstruction leads to increased pressure in the upper body and decreased pressure in the lower body. As a result, one of the key clinical features of CoA is weak or absent femoral pulses, which can be detected during a physical examination. This finding is due to reduced blood flow past the point of coarctation, affecting the blood supply to the lower extremities.

Imagine a garden hose that has a tight pinch in the middle. Water pressure before the pinch is high, but after the pinch, the flow is significantly reduced. Similarly, in CoA, the blood flow and pressure before the narrowed section are high, but after the narrowing, the flow and pressure drop significantly, leading to weak or absent pulses in the legs.

The coarctation of the aorta creates an obstruction that the heart must work harder to overcome, leading to hypertension in the upper body (arms and head) and hypotension in the lower body (legs). The reduced blood flow to the lower extremities results in weaker or absent femoral pulses, a hallmark finding in this condition. Blood pressure measurements will often show a significant difference between the upper and lower extremities.

✘Incorrect answer options:

Preference for a squatting posture. This is typically associated with tetralogy of Fallot, where children may squat to increase systemic vascular resistance and improve oxygenation.

Episodes of cyanosis ("tet" spells). "Tet" spells are also associated with tetralogy of Fallot, not coarctation of the aorta. These spells are characterized by sudden episodes of cyanosis due to decreased oxygenation.

Intense cyanosis immediately after birth. This is characteristic of severe congenital heart defects such as transposition of the great arteries or severe pulmonary stenosis, where immediate intervention is often required. Coarctation of the aorta typically presents with differential cyanosis, affecting the lower extremities more than the upper.

EXPLANATION

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Apex. The apex of the heart refers to the bluntly rounded lower tip of the heart. It is located at the bottom of the heart and points downward, forward, and to the left. The apex is an important landmark in cardiac anatomy and is the point where the heart's strongest contractions are felt, typically where the apical pulse can be auscultated or palpated.

Think of the heart as an upside-down pear. The narrow, pointed end of the pear is analogous to the apex of the heart, which is the lower tip.

The apex of the heart is formed by the left ventricle. It is the site where the strongest impulse can be felt during a heartbeat and is an important reference point for clinicians when assessing heart function and position. The apex is typically located in the fifth intercostal space at the midclavicular line.

✘Incorrect answer options:

Aorta. The aorta is the largest artery in the body, responsible for carrying oxygenated blood from the left ventricle to the rest of the body. It is not related to the tip of the heart.

Base. The base of the heart is the upper, broad part of the heart where the major blood vessels attach. It is opposite the apex and does not refer to the lower tip of the heart.

Pericardium. The pericardium is the double-walled sac that surrounds and protects the heart. It is not a specific part of the heart's anatomy but rather the protective covering around it.

EXPLANATION

✔Correct answer:

A blockage impedes blood flow from the right ventricle. Pulmonic stenosis (PS) is a heart condition characterized by a narrowing (stenosis) at the pulmonary valve or just below it, which obstructs the flow of blood from the right ventricle to the pulmonary artery. This obstruction increases the pressure in the right ventricle as it works harder to pump blood through the narrowed valve, leading to right ventricular hypertrophy over time. It's crucial for parents to understand that this blockage can impact the efficiency of blood flow to the lungs for oxygenation.

Imagine a garden hose with a kink in it. The water (blood) still flows, but the hose (right ventricle) has to work much harder to push the water through the kink (narrowed pulmonary valve). This extra effort can cause the hose to wear out faster, just as the right ventricle can become thickened and less efficient over time.

The pulmonary valve is located between the right ventricle and the pulmonary artery. In pulmonic stenosis, the narrowing of this valve restricts blood flow, causing the right ventricle to pump harder to push blood into the pulmonary artery. Over time, this increased workload can lead to hypertrophy (thickening) of the right ventricular muscle. Proper management and monitoring are essential to prevent complications and ensure adequate blood flow to the lungs for oxygenation.

✘Incorrect answer options:

Blood returning to the heart bypasses the left atrium. This describes an atrial septal defect or another abnormal connection between the atria, not pulmonic stenosis.

One blood vessel originates from both the left and right ventricles. This describes a condition known as truncus arteriosus, where a single blood vessel comes out of the heart and supplies blood to both the systemic and pulmonary circulations. It is not related to pulmonic stenosis.

A blockage hampers blood flow from the left ventricle. This describes aortic stenosis, where there is a narrowing of the aortic valve, impeding blood flow from the left ventricle to the aorta. It is not the same as pulmonic stenosis, which affects the right ventricle.

EXPLANATION

✔Correct answer:

It redirects the combined cardiac output from the pulmonary artery directly into the systemic circulation. The ductus arteriosus is a crucial vessel in fetal circulation that connects the pulmonary artery to the aorta. During intrauterine life, the lungs are not yet functional, and the fetus receives oxygenated blood from the placenta. The ductus arteriosus allows most of the blood from the right ventricle to bypass the non-functioning lungs and flow directly into the systemic circulation, ensuring that oxygen-rich blood is delivered to the body.

Think of the fetal circulation system like a temporary bypass road that diverts traffic away from a closed section of the main road (the lungs) and allows cars (blood) to reach their destination (the body) more efficiently.

In fetal circulation, the right ventricle pumps blood into the pulmonary artery. Instead of traveling to the lungs, most of this blood is diverted through the ductus arteriosus into the aorta. This mechanism ensures that oxygenated blood from the placenta is efficiently distributed to the fetal body. After birth, the ductus arteriosus typically closes as the lungs become functional and the normal adult circulation pattern is established.

✘Incorrect answer options:

It channels the combined cardiac output from the aorta to the pulmonary artery and then to the right ventricle. This description does not accurately reflect the function of the ductus arteriosus. Blood flows from the pulmonary artery to the aorta, not the other way around.

It diverts the combined cardiac output from the aorta to the pulmonary artery, which then leads to the pulmonary veins. This option incorrectly describes the flow of blood. The ductus arteriosus does not involve the pulmonary veins; it directs blood from the pulmonary artery to the aorta.

It transfers the combined cardiac output from the pulmonary artery to the aorta and then to the lungs. This option incorrectly suggests that blood flows to the lungs after passing through the aorta, which is not the case. The ductus arteriosus diverts blood away from the lungs.