Cardiac shunts

Question 1

What is the ductus venosus? When does it close?

Answer 1

Allows blood to bypass the liver

Umbilical vein to the IVC

Clamping of the cord

Question 2

What is the foramen ovale? When does it close?

Answer 2

Allows blood passage from RA to LA to bypass the lungs

3 days

Question 3

What is the ductus arteriosus? When does it close?

Answer 3

Shunts blood away from pulmonary trunk

Pulmonary artery to the proximal descending aorta

Weeks after birth

Question 4

How does PVR and SVR compare in fetal circulation to adults?

Answer 4

PVR is high in fetus
SVR is low in fetus

Question 5

Which organ is responsible for respiration in the fetus? How is circulation arranged?

Answer 5

Placenta for respiration

Circulation is arranged in parallel

Question 6

What type of shunting occurs in the fetus?

Answer 6

R - L across foramen ovale and the ductus arteriosus

Question 7

Is there pulmonary blood flow in the fetus? Is left atrial pressure high or low?

Answer 7

Minimal pulmonary blood flow

LA pressure is low

Question 8

What happens to PaO2, PaCO2, and PVR when baby takes first breath of life?

Answer 8

PaO2 Increases

PaCO2 Decreases

PVR Decreases

Question 9

What happens to the placenta and SVR when baby takes first breath of life?

Answer 9

Placenta detaches and SVR increases

Question 10

How does the foramen ovale close when baby takes first breath of life?

Answer 10

Decreased PVR and Increased SVR cause higher pressure in the LA than the RA and the flap closes

Question 11

How does the ductus arteriosus close?

Answer 11

Decreased PVR reverses blood which exposes the Ductus arteriosus to oxygen which closes it

Additionally, decreased prostaglandins allow the DA to close

Question 12

What is the risk of the foramen ovale staying open?

Answer 12

PFO increases the risk of a paradoxical embolism to the brain (not lungs)

Question 13

What drugs can open the ductus arteriosus? Close it?

Answer 13

Close - indomethacin

Open - Prostaglandin E1

Question 14

How is PVR calculated?

Answer 14

Question 15

How is SVR calculated?

Answer 15

Question 16

How does hypercarbia/hypocarbia affect PVR?

Answer 16

Hyper - Increases

Hypo - Decreases

Question 17

How does hypoxemia affect PVR?

Answer 17

Increases

Question 18

How does acidosis/alkalosis affect PVR?

Answer 18

Acidosis - Increases
Alkalosis - Decreases

Question 19

How does pain and light anesthesia affect PVR?

Answer 19

Increases

Question 20

How does hypothermia affect PVR?

Answer 20

Increases

Question 21

How does vasoconstrictors/dilators affect PVR?

Answer 21

Constriction - Increases

Dilation - Decreases

Question 22

How does Trendelenburg and collapsed alveoli affect PVR?

Answer 22

Increases

Question 23

How does anxiety affect SVR?

Answer 23

Increases

Question 24

How does histamine and anaphylaxis affect SVR?

Answer 24

Decreases

Question 25

What is a R to L shunt called? What happens?

Answer 25

A cyanotic shunt Venous blood bypasses the lungs

Question 26

Examples of cyanotic shunt?

Answer 26

5 T's 1. Tetralogy of Fallot 2. Transposition of great arteries 3. Tricuspid abnormality 4. Truncus arteriosus 5. Total anomalous pulmonary venous connection

Question 27

What is the most common cyanotic shunt?

Answer 27

Tetralogy of Fallot

Question 28

What are the hemodynamic goals of R-L shunt?

Answer 28

Maintain SVR and Decreases PVR

Question 29

What is a L to R shunt called?

Answer 29

Acyanotic shunt where blood from the left side recirculates through the lungs

Question 30

Most common acyanotic shunt? Other examples?

Answer 30

Ventricular septal defect Atrial septal defect Patent ductus arteriosus Coarctation of aorta

Question 31

Hemodynamic goals of L to R shunt?

Answer 31

Avoid increased SVR Avoid decreased PVR

Question 32

L-R shunt, slower or faster inhalation induction?

Answer 32

Minimal effect

Question 33

R-L shunt, slower or faster inhalation induction?

Answer 33

Slower induction

Question 34

L-R shunt, slower or faster IV induction?

Answer 34

Slower induction

Question 35

R-L shunt, slower or faster IV induction?

Answer 35

Faster induction

Question 36

What is Eisenmenger syndrome?

Answer 36

When a patient with L-R shunt develops pulmonary HTN and reverses flow which now causes a R-L shunt

Question 37

What are the 4 defects with tetralogy of Fallot?

Answer 37

1. RV outflow tract obstruction 2. RV hypertrophy 3. Ventricular septal defect 4. Overriding aorta because it's receiving blood from both ventricles

Question 38

What is Tet spell?

Answer 38

Increased sympathetic activity which increases myocardial contractility thus leading R to L shunt and hypoxemia

Question 39

Who can experience Tet spells? Examples of how they occur?

Answer 39

Children with unrepaired tetralogy of Fallot -Crying -Agitation -Pain -Pooping -Trauma -Scared

Question 40

How do children try to treat Tet spells on their own?

Answer 40

Squat and bear down which increase SVR and blood flow thus restoring blood flow

Question 41

How does anesthesia treat Tet spells?

Answer 41

-100% FiO2 -Increased Volume -Phenyl to increase SVR -Reduce SNS -Knee to chest position

Question 42

What does anesthesia avoid with Tet spells?

Answer 42

Inotropes because of an increased RVOT obstruction High airway pressures

Question 43

Goals for tetralogy of Fallot?, SVR, PVR, HR, Contractility, Preload?

Answer 43

SVR - Increase PVR - Decrease HR - Maintain Contractility - Maintain Preload - Increase

Question 44

Best drug for induction of tetralogy of Fallot?

Answer 44

Ketamine 1-2mg IV 2-4mg IM

Question 45

Most common congenital anomaly in infants/children and adults?

Answer 45

Infants/Children - VSD most close by 2 years old Adult - Bicuspid aortic valve

Question 46

What is the coarctation of the aorta? What is highly associated with this?

Answer 46

Narrowing of the thoracic aorta Turner syndrome

Question 47

Coarctation of the aorta, how is BP affected?

Answer 47

SPB is elevated in UE SPB is reduced in LE

Question 48

What is Epstein anomaly?

Answer 48

Congenital defect of the tricuspid valve SVT is common R-L shunt RV failure Tricuspid regurgitation

Question 49

What is a fontan completion ?

Answer 49

The patient has a single ventricle that pumps blood into the systemic circulation and no blood to pump into the pulmonary circuit

Question 50

What do people with fontan completion rely on?

Answer 50

Negative pressure during spontaneous breathing? Preload dependent DO NOT let them become dry or use positive pressure ventilation

Question 51

What is truncus arteriosus?

Answer 51

A single artery that rives rise to the pulmonary, systemic, and coronary circulations

Question 52

Cardiac circulation in adults? Fetus? Series or Parallel?

Answer 52

Adult - Series Fetus - Parallel

Question 53

How does Nitric Oxide effect PVR?

Answer 53

Decreases

Question 54

How does hemodilution effect PVR and SVR?

Answer 54

Decreases both

Question 55

RV hypertrophy causes what type of axis deviation?

Answer 55

Right axis deviation

Question 56

Which drugs should be avoided in the patient with tetralogy of Fallot?

Answer 56

Drugs that have histamine release Inotropes

Question 57

Which drugs have histamine release?

Answer 57

Morphine Meperidine Atracurium

Question 58

Why are some patients with tetralogy of Fallot polycythemic?

Answer 58

Because the chronic hypoxemia stimulates RBC production

Question 59

What is a Tet Spell?

Answer 59

Increased SNS activity causes an increase in myocardial contractility and causes RVOT

Question 60

Management of PVR for tet spells?

Answer 60

Avoid increase

Question 61

Management of SVR for tet spells?

Answer 61

Increase

Question 62

Management of Contractility for tet spells?

Answer 62

Maintain

Question 63

Management of HR for tet spells?

Answer 63

Maintain

Question 64

What is the most common VSD type?

Answer 64

Peri membranous

Question 65

What is the most common ASD type?

Answer 65

Secundum which is in the middle of the atrial septum

Question 66

What is the most common congenital defect in children?

Answer 66

VSD

Question 67

Should antibiotics be given for a VSD?

Answer 67

No - only within 6 months of surgical repair

Question 68

When does the VSD usually close by?

Answer 68

2

Question 69

What is the biggest concern for VSD? Which disease?

Answer 69

Eisenmenger's When the L-R shunt turns into a R-L shunt because of high PVR

Question 70

PVR and SVR management for a VSD?

Answer 70

Avoid increased SVR and avoid decreased PVR

Question 71

What is an early symptom of ASD?

Answer 71

Poor exercise tolerance

Question 72

Best site to monitor arterial BP during the repair of coarctation of aorta?

Answer 72

R arm because left subclavian maybe narrowed thus causing reduced perfusion to the ULE

Question 73

Treatment for severe obstruction of coarctation of the aorta?

Answer 73

Need to keep a patent ductus arteriosus to prevent hemodynamic collapse

Question 74

In severe coarctation of the aorta, what does the lower body rely on for perfusion?

Answer 74

A patent ductus arteriosus

Question 75

What are 2 cardiac signs of coarctation of the aorta?

Answer 75

Systolic BP is greater in the upper extremities vs the lower extremities Differential cyanosis

Question 76

What is the most common single ventricle lesion?

Answer 76

Hypoplastic left heart syndrome

Question 77

What is Ebstein's anomaly?

Answer 77

Downward displacement of the tricuspid valve

Question 78

How is IV induction affected by Ebstein's anomaly?

Answer 78

Slower due to pooling of drugs

Question 79

Common rhythm with Ebstein's anomaly?

Answer 79

SVT

Question 80

Tricuspid regurg or stenosis with Ebstein's anomaly?

Answer 80

Regurg