The nurse has provided education about the administration of prostaglandin to the parent of an infant diagnosed with Tetralogy of Fallot (ToF) who is experiencing cyanosis from a severe obstruction of the right ventricle. Which statement made by the parent indicates the teaching has been successful?

“The medication will allow blood flow to the lungs while you are preparing my baby for surgery.”

“The medication will prevent the right ventricle from collapsing before my baby is taken to surgery.”

“The medication will decrease the workload of the heart to prevent heart failure while my baby is waiting for surgery.”

“The medication will allow blood flow to the lungs while you are preparing my baby for surgery.”

“The medication will help improve the electrical conduction of my baby’s heart.”

Tetralogy of Fallot: Nursing

Definitions & Key takeaways

Tetralogy of Fallot, or TOF, is a congenital disorder characterized by four heart abnormalities. There is stenosis in the right ventricular outflow tract, right ventricular hypertrophy, ventricular septal defect, and aortic override of the septal defect. These four defects cause oxygen-poor blood to flow from the right ventricle into the aorta, rather than being pumped to the lungs, which results in cyanosis. TOF is diagnosed with patient examination and health ultrasound, and treatment involves cardiac surgical repair, usually in the first year of life.

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Introduction0:00–0:17

Tetralogy of Fallot, or ToF, is the most common congenital heart defect. Similarly to pulmonary stenosis, the cause of ToF is unknown, but genetic factors likely play a role in its development.

Four different defects0:17–1:05

ToF consists of four different defects. These defects include pulmonary stenosis, right-ventricular hypertrophy, VSD and an overriding aorta, which happens when the aorta is displaced and blood from both sides of the heart is able to flow through it.

In some clients a fifth defect, ASD, may be present. Since all of these factors can lead to right to left shunting of blood, ToF can also be classified as a cyanotic heart condition.

Now, the direction of the shunting in ToF isn’t always right to left. In this condition, it depends on the severity of the obstructive defects and the pressure difference between pulmonary vascular resistance and systemic resistance.

Pulmonary vascular resistance vs systemic resistance1:05–1:54

Pulmonary vascular resistance is the amount of force exerted against blood flow from the pulmonary artery to the left atrium; and systemic resistance is the amount of force exerted on circulating blood by the vasculature of the body.

So if the pulmonary vascular resistance is greater than systemic resistance, blood will shunt from right to left. But, if the systemic resistance is greater than pulmonary vascular resistance, blood will shunt from left to right.

In this situation, excess oxygenated blood from the left ventricle will shunt over to the right ventricle through that VSD.

These clients are at risk for developing pulmonary congestion since all this extra blood volume shunting over to the right side will make its way to lungs.Now, symptoms can vary broadly in different clients, some with just mild symptoms, while others can have a much more severe experience.

Symptoms1:54–4:07

The wide difference in symptoms is directly related to how much blood gets oxygenated. These symptoms of ToF can be present at birth, and the infant may appear cyanotic, like in right to left shunting scenarios; or acyanotic, like in left to right shunting scenarios.

These are sometimes referred to as “blue baby syndrome” and "pink baby syndrome". In other cases, cyanosis may be less acute initially, but can progress over the first 12 months of life; specifically as the pulmonary stenosis defect worsens.

Another common initial finding in infants with ToF is a characteristic loud and harsh heart murmur. Now, with a right to left shunting of blood, the body’s demand for oxygen exceeds what’s available in the blood supply, since less blood reaches the lungs.

When this occurs, infants and children can experience hypercyanotic spells, called “blue spells” or “tet spells”. These spells can be particularly worrisome to parents, guardians or caregivers of the child during this time because they can become extremely cyanotic and appear to be starving for air.

In more severe cases, the child may pass out, lose consciousness or even experience convulsions. Episodes like this can last anywhere from a few minutes to a few hours.

This is a very exhausting experience for a child, so muscle weakness and a long period of sleep can be expected afterwards.

Actions like crying, feeding or having a bowel movement are common causes of these spells, because these actions increase the body’s demand for oxygen.

Additional signs and symptoms of ToF that can be found in infants and children include dyspnea, poor feeding, and fatigue.

Chronic hypoxia can also lead to clubbing of fingers, toes and polycythemia.A unique event that can be seen in children with ToF is “squatting.” This is a compensatory mechanism in response to decreased oxygenation.

Squatting4:07–6:19

The act of squatting increases peripheral vascular resistance and diminishes the right to left shunting of blood. As a result, blood flow increases through the pulmonary artery to the lungs, allowing for more blood to become oxygenated.

Interestingly, infants who experience hypercyanotic spells can also benefit from knee-to-chest positioning, as it results in the same outcomes of squatting.

Confirming the diagnosis of ToF can be done through physical exam and diagnostic tests, like ECGs, echocardiogram, chest x-ray and cardiac catheterization.

The definitive treatment for ToF is surgical correction of the defects, and this is best accomplished during infancy.Initially, treatment can be palliative, with more invasive procedures done later on as the child grows.

Depending on the severity, specific surgical procedures will be selected. If severe symptoms or a severe obstruction from the right ventricle is present, the client should receive IV prostaglandins to keep the ductus arteriosus open until surgery can be performed.

This can be an added benefit, as it allows for blood to flow to the lungs, despite the obstructive nature of ToF. For several clients who have undergone surgical correction of ToF, the prognosis is very good.

However, most clients still experience long-term complications. One of the most common being pulmonary regurgitation, which happens when the pulmonary valves don’t fully close and blood leaks backwards into the right ventricle.

This backwards leakage can cause the ventricle to dilate and enlarge. Luckily, by maintaining routine follow-up visits with their healthcare providers, clients who have undergone correction of ToF can continue to manage their condition and live a quality life.

OK, so a quick recap. Tetralogy of Fallot, or ToF, is the most common congenital heart defect.

Summary6:19–7:45

ToF consists of four different defects; pulmonary stenosis, right-ventricular hypertrophy, VSD and an overriding aorta. In some clients a fifth defect, ASD, may be present.

The direction of blood shunting in ToF depends on the severity of the obstructive defects and the pressure difference between pulmonary vascular & systemic resistance.

Symptoms can vary broadly in different clients, some with just mild symptoms, while others can have a much more severe experience.

These symptoms of ToF can be present at birth, and the infant may appear cyanotic or acyanotic, sometimes referred to as “blue baby syndrome” and "pink baby syndrome".

Additional signs and symptoms of ToF include dyspnea, poor feeding, fatigue. Confirming the diagnosis of ToF can be done through physical exam and diagnostic tests, but the definitive treatment for ToF is surgical correction of the defects, and this is best accomplished during infancy.

Luckily, through health promotion and maintenance with their healthcare providers,