Foetal Circulation

Question 1

What are the main functions of the placenta?

Answer 1

1. Gas exchange
2. Nutrients
3. Waste exchange
4. Homeostasis

Question 2

Which organs are important in foetal circulation? Order of circulation?

Answer 2

placenta–>heart–>lungs and body. Then back to heart–>placenta.

Question 3

What is the name of the artery/vein that supplies blood from heartplacenta?

Answer 3

Umbilical A&V

Question 4

What are the “3 shunts” specific to foetal life?

Answer 4

1. Formaen ovale
2. Ductus arteriosus
3. Ductus venosus?

Question 5

What is the role of the ductus venosus?

Answer 5

connects umbilical vein to inferior vena cava

Question 6

What is the role of the foramen oval?

Answer 6

Opening in atrial septum. flow from RA–> LA.

Question 7

What is the role of ductus arteriosus?

Answer 7

Connects pulmonary bifurcation to descending aorta.

Question 8

Whys is the foramen ovale important?

Answer 8

Right side brings oxygenated blood from placenta. Foramen ovale allows left side of the heart to receive this and send it through the aorta into the carotids etc.

Question 9

Which side of the heart has a higher BP in a foetus?

Answer 9

Right

Question 10

Why’s the ductus arteriosus important?

Answer 10

Allows most of the blood to go into the descending aorta from RV output. only 7% goes to lungs.

Question 11

BONUS question- Why are NSAID’s contraindicated in pregnancy?

Answer 11

NSAIDS like ibuprofen inhibit Prostaglandin E2, important for foetal patency

Question 12

What happens to pulmonary and systemic vascular resistance minutes after the baby is born?

Answer 12

1. PVR- decreases, lungs fully expand allowing air in.

2. SVR- Increases. Increases Cardiac Output to lungs.

Question 13

What a happens to the foramen ovale soon after? Why?

Answer 13

Pushed close. LA pressure becomes higher than RA.

Question 14

What happens to the ducts? Why?

Answer 14

Constriction. Increased Po2. Reduced blood flow

Question 15

What problems can arise with duct changes?

Answer 15

• Might not fully close.

- Might have duct dependent circulation

Question 16

What is PPHN (hint-pulmonary h)

Answer 16

Lung vascular resistance remains high.
Shunts between right and left side remain at
- Patent foramen ovale
- patent ductus arteriosus
"Blue" baby,

Question 17

Immediate management for PPHN?

Answer 17

• Ventilation
• High flow 02
• inhaled Nitric oxide