19. Congenital Defects Part 2

Question 1

1. What are the characteristics of a Cyanotic CHD? (3 things)
2. What 3 possible disorders fall under this category?

Answer 1

1. Not ductal dependent, R -> L shunt, venous-arterial mixing
2. Tetrology of Fallot (TOF)
   Truncus Arteriosus (TA)
   Total Anomalous Pulmonary Venous Return (TAPVR)

Question 2

1. How common is TOF?

2. TOF consists of 4 associated conditions. What are they?

Answer 2

1. Occurs in 10% of all infants born with CDH

2. Overriding aorta, pulmonary stenosis, VSD, Right Ventricular Hypertrophy

Question 3

1. What does the severity depend on in TOF? What does the degree of cyanosis depend on?
2. Mild pulm. stenosis (not common): Is blood flow restricted from RV to lungs? What kind of shunt is present? What is it known as?
3. Severe pulm. stenosis (COMMON): Is blood flow restricted from RV to lungs? What kind of shunt is present? Is the baby cyanotic?
4. What are the 2 characteristics of very severe stenosis?

Answer 3

1. Severity depends on degree of RV outflow obstruction with pulmonary stenosis, degree of cyanosis depends on the pulmonary stenosis
2. Blood flow is not restricted from RV to lungs, L -> R shunt across VSD, known as cyanotic “pink TET”
3. Blood flow restricted from Rv to lungs, R -> L shunt across VSD, cyanotic
4. Ductal dependent, requires PGE1

Question 4

1. S&S with TOF? (Hint: 5)

2. CXR findings? (Hint: 2 common findings)

Answer 4

1. Cyanosis, murmur, SOB and tachypnea, poor feeding & poor weight gain, episodes of cyanosis with feeding or crying
2. Normal sized, boot shaped heart, as well as decreased pulmonary vascular markings (lungs appear darker) if decreased blood flow with stenosis

Question 5

What are hypercyanotic or TET spells? What age do they often occur? What are they caused by? (Hint: 3 things)
2. What occurs anatomically when a TET spell happens? What does this cause an increase of, what does it worsen, and what can happen from this? (Hint: 2 things it worsens)

Answer 5

1. Spells of profound cyanosis, they occur at 2-4 months and can be caused by defecating, feeding, or crying
2. Spasm of pulm. artery, or sudden decrease in SVR, this causes an increase in R -> L shunting across the VSD. This causes worsening cyanosis which can further increase PVR and worsen shunt

Question 6

1. How do you treat a TET spell? (2 large options)
2. What are the 3 common treatments to soothe the infant during a spell?
3. What are the 3 less common treatments?

Answer 6

1. Increase SVR to decrease R -> L shunting across VSD, Increase pulm. blood flow and oxygenation
2. Calm infant (give morphine), knee-chest position (Increase SVR in lower extremities and decrease shunt), O2 therapy and support of ventilation (Decrease PVR)
3. Vasoconstrictors (Phenylephrine to increase SVR), NaHCO3 (to correct acidosis), propranolol (ACE inhibitor, reduce pulm. spasm)

Question 7

1. What are the treatments for TOF itself? (Not TET spells) (Hint: 3)
2. What is the name of the surgical procedure to aid with pulmonary blood flow? What is the name of the definitive repair?

Answer 7

1. Minimize handling, prostaglandin treatment to maintain potency of DA in severe pulm. stenosis
2. Blalock-Taussig shunt (palliative procedure), intracardiac repair

Question 8

What is Total Anomalous Pulmonary Venous Return (TAPVR)? How common?

Answer 8

All 4 pulmonary veins do not connect normally to the left atrium, but instead drain abnormally to the right atrium by way of abnormal connection, common in 10% of infants with CHD

Question 9

1. What is the pathway of blood in this disorder from RV?
2. What way is the shunt?
3. Is there cyanosis? What about the RV, is it okay?

Answer 9

1. RV-PA-PC-PV-RA (but last step should be LA)
2. R -> L through ASD
3. Yes, and there is an increased volume load on the RV

Question 10

1. TAPVR is classified based on the _________ of the abnormal pulm. vein.
2. Based on this, how common are each of the following, and starting from the Pul vein, what is the pathway of blood for each?
   - Supracardiac, Cardiac, Infracardiac, Mixed
3. Which of the pathways is the most concerning and why?

Answer 10

1. Location
2. Supracardiac (50%): Pul vein -> innominate vein -> SVC -> RA
   Cardiac (20%): Pul vein -> coronary sinus -> RA
   Infracardiac (20%): Pul vein -> via long and tortuous route -> IVC -> RA
   Mixed (10%): Pul vein -> multiple connections -> RA (supra cardiac, cardiac, and/or infra cardiac types)
3. Infracardiac, because high incidence of obstruction to pulm. venous outflow