Foetal Circulation and congenital CVD Flashcards
What is the placenta’s function?
Fetal homeostasis Gas exchange Acid base balance Nutrient transport to fetus Waste product transport from fetus Hormone production Transport of IgG PGE2
What is Prostaglandin E2 important for?
- mainitng the foetal circulation
- can be given to maintain patency after birth if required in certain congenital heart diseases
What are the lungs filled with in the feotus?
- fluid filled and unexpanded
Are the lungs involved in foetal circulation?
- small amounts of blood enters the lungs so they get the nutrients to grow
- the placenta is what oxygenates the blood
Where does the placenta sit in foetal circulation
- at the end of the umbillica cord
- umbalical arteriers branch off the descending aorta to the placenta
In the umbilical cord the arteries carry_______ blood
oxygenated or deoxygenated?
- deoxygenated
In the umbilical cord the veins carry_______ blood
oxygenated or deoxygenated?
- oxygenated
Name the 3 shunts of foetal circulation?
- ductus venosus
- foramen ovale
- ductus arteriosus
What is the ductus venousus
- Connects the umbilical vein to the inferior vena cava
- doesnt get processed in the liver
- vascular structure
What is the Foramen ovale
- Opening in atrial septum connecting RA to LA
- allows oxygenated blood to enter the left ventrical and then to the foetal body and brain
What is the ductus arteriosus?
- Connects pulmonary bifurcation to the descending aorta
Right ventricle contains _____ blood?
- oxygenate/deoxgenated/ partially oxygenated
- partially oxygenated blood
Ductus arteriosus is the pathway with the _____ resistance?
- least
Where is bood from the inferior vena cava in foetal circulation encouraged to go?
- encourage to go through the foramen ovalve
- into the left atrium
What produces prostaglandin E2 in the fetus?
- the placenta
What circulator changes will occur as soon as a baby is born, in terms of pulmonary and systemic vascular resistance?
- PVR will decrease as the lungs physically expand
- SVR increases and the cord clamped and cut
Once a baby is born and taken its 1st breath, what happens to the foramen ovale
- pressure in the left side of the heart becomes higher than the right (opposite of when they were in womb)
- blood no longer flows through foramen ovale cause of pressure
- the flap of foramen ovale closes
What causes the foramen ovale to close in terms of nutrients?
- Increased pO2 – oxygen sensitive muscular layer
- Decreased circulating PGE2 due to increased lung metabolism and placenta being removed
What are complications of the ductus arteriosus after birth?
- the duct may fail to close
- may lead to respiratory and circulatory complications
How would you treat a failed closure of ductus arteiosus?
- Nonsteroidal anti-inflammatory drugs (NSAIDs)
- may close natural over time
- surgery
What is the primary problem that causes Persistent Pulmonary Hypertension of the Newborn?
- lung vascular resistance fails to fall
Treatment of Presistent Pulmonary Hypertension of the Newborn?
- ventilation
- oxygenation
- increasing systemic blood pressure
- inhaled nitric oxide
- ECLS (extra-corporeal life support)
- sedation
How would you increase systemic vascular resistance in a newborn? for PPHN
- inotropes
When are congenital heart disease diagnosed?
- antenatal screening
- soon after birth
- day 1-2 check
- and from there on
Management of antenatally diagnosed CHD?
- Depends on disease
- may decide to deliver in cardiac surgical centre
- prostaglandin infusion if duct dependent lesion
Differential diagnosis of cyanosis in a newborn?
- cardiac disease
- respiratory disease
- persistent pulmonary hypertension of the newborn (PPHN)
What happens if the ductus arteriosus closes in a congenital heart defect?
- often between 2-7 days
- severe cyanosis
- tachypnoea
- rapid deterioration / death
- poor/absent pulse
- acidotic
Treatments of congenital heart disease?
- surgery
- valves
- transplant
- emotional and social help
