Embryology

Question 1

Function of the ductus venosus?

Answer 1

Bring oxygenated and nutrient rich blood from the placenta to the right atria.

Question 2

Foramen Ovale

Answer 2

A gap in the atria walls allowing oxygenated blood to pass into the left atria and then the systemic system

Question 3

Ductus arteriosus

Answer 3

Connects the bifurcated pulmonary artery to the descending aorta

Question 4

Why does very little blood reach the lungs?

Answer 4

The pulmonary pressure is much higher as the lungs are dense with no air in them so most blood passes into left atria and via the ductus arteriosus.

Question 5

Why is the foramen ovalis open?

Answer 5

The pressure in the right atria is much higher than in the left so the pressure gradient ensures it stays open.

Question 6

What vital stage after birth is key for the babies survival?

Answer 6

To take a large breath in and to cry as this creates a backlog of pressure into the lungs that forces them open. This reduces the pulmonary and right heart pressure.

Question 7

Why upon birth does the foramen ovalis close?

Answer 7

As the pressure in the right atrium has fallen whilst the systemic pressure has increased to the pressure gradient is reversed closing the foramen.

Question 8

Why does the ductus venosus close?

Answer 8

As the umbilical chord is clamped and cut so there is no flow though it so it closes.

Question 9

What keeps the ductus arteriosus open?

Answer 9

Prostaglandin E2 acts as a potent vasodilator on the ductus.

Question 10

Why does the ductus arteriosus close upon birth?

Answer 10

As the placenta where prostaglandin E2 is produced is detached so no supply of prostaglandin E2.

Question 11

At what stage is the anatomical closure of the foramen ovalis completed?

Answer 11

7-10 days

Question 12

What does the ductus arteriosus become?

Answer 12

The fibrous ligamentum arteriosum

Question 13

Which group have a higher risk of patent ductus arteriosus?

Answer 13

Preterm babies

Question 14

What does PPHN stand for?

Answer 14

Persistant pulmonary hypertension of newborns

Question 15

What is the issue with PPHN?

Answer 15

Systemic blood contains lots of deoxygenated blood as foramen ovalis and ductus arteriosus remain functional

Question 16

What signs show that there is PPHN

Answer 16

Baby remains blue and continual murmur as patent ductus arteriosus

Question 17

What check can be done to help diagnose?

Answer 17

pO2 check on right arm and a foot, as the right arm should have a much higher pO2 as it branches off before the ductus arteriosus enters.

Question 18

Treatment for PPHN

Answer 18

Oxygen, ventilation, sedation, thermoregulation, correct acidosis, inhale NO (reduces pulmonary vascular resistance)

Question 19

Babies should be kept cool yes or no?

Answer 19

Being cold as a baby is extremely dangerous as cold has a bigger effect on the pulmonary vasculature increasing risk of PPHN

Question 20

What is the difference between cardiac and respiratory cyanosis?

Answer 20

Both babies appear blue, but in cardiac the baby doesn’t seem particularly uncomfortable no grunting etc

Question 21

At what check is the structure of the heart valves usually detected?

Answer 21

The antenatal check using ultrasound

Very dependent on the mother and experience of operator

Question 22

Day 1-2 Check

Answer 22

Murmurs cyanosis abnormal pulses

Question 23

Day 3-7 checkup

Answer 23

Usually duct dependant issues picked up

Sudden circulatory collapse, shock, cyanosis, death

Question 24

4-6 week check up

Answer 24

Signs of cardiac failure, reduced feeding failure to thrive, lung crepitations, hepatomegaly

Question 25

6-8 weeks

Answer 25

GP check up

Murmurs, failure to thrive breathlessness

Question 26

Why do duct dependant issues arise around 3-7 days

Answer 26

As this is when the ductus arteriosus is closed off

Question 27

Duct dependant conditions

Answer 27

Interrupted aortic arch
Aortic atresia
Hypoplastic left ventricle

Question 28

Treatment for duct dependant conditions?

Answer 28

IV prostaglandin E2 until surgery is available

Question 29

Transposition of the great vessels

Answer 29

Uncompatible with life unless Foramen ovalis is open

Question 30

Signs of transposition of the great vessels

Answer 30

Cyanosis, sever acidosis, tachypnoea, hepatomegaly, lung crepitations