Perinatal Adaptation Flashcards by Jane Keery

Which type of antibody can pass via the placenta?

Is this done via active or passive transport?

IgG

Active transport

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What contributes to the formation of amniotic fluid?

The baby swallows the amniotic fluid for what purpose?

What can be a sign of kidney failure in the baby?

Fluid produced by the baby’s lungs, and urine produced by the baby’s kidneys

To develop the GI system

Oligohydramnios

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The foetal circulation differs from the adult circulation mainly due to the presence of 3 shunts. What are these?

Foramen ovale

Ductus arteriosus

Ductus venosus

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Only 7% of cardiac output in a foetus goes to the lungs - why is this?

What is the function of the 7% that does go to the lungs?

Because all gas exchange and nutrition takes place in the placenta (the lungs are not in use)

To allow them to grow

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In a foetus, the vascular resistance in the lungs is very what? What would it be in adults?

In a foetus, the vascular resistance in the placenta is very what?

High / Low

Low

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Complete the sentence:

Oxygenated blood from the placenta travels to the foetus in the ?

This blood then travels into the ?, bypassing the liver via the ?

Umbilical vein

IVC / Ductus venosus

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In an adult, blood from the IVC would travel into which heart chamber?

Due to the presence of the foramen ovale in the foetus, where does this blood go?

Right atrium

Left atrium

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In the foetal circulation, the blood from the IVC passes straight into the left atrium. Where does it go from here?

The small majority of blood that does pass into the right atrium goes to where?

The majority goes to supply the brain and systemic circulation

The lungs

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What is the role of the ductus arteriosus?

To allow blood from the pulmonary artery to pass into the aorta to join the systemic circulation

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Deoxygenated blood from the foetal body returns to the placenta via which vessels?

The umbilical arteries

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What happens to foetal blood which enters the right ventricle?

It passes into the pulmonary trunk and then is diverted into the aorta via the ductus arteriosus

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Why does blood pass through the foramen ovale?

What does this allow?

Because the pressure in the right atrium is higher than the pressure in the left atrium

Foetal blood to bypass the pulmonary circulation

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In terms of circulation, what happens when a baby takes its first breath?

The resistance in the pulmonary circulation drops which causes blood from the RA to enter the RV, redistributing blood flow across the pulmonary arteries

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What happens to each of the following things following delivery:

Pulmonary vascular resistance?

Systemic vascular resistance?

Oxygen tension?

Blood vessels?

Circulating prostaglandins?

Decreases

Increases

Relax

Decreases

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As the placenta disappears, and the umbilical vein flow disappears, which duct will be lost?

The ductus venosus

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The foramen ovale closes for 3 reasons, what are these?

Which one of these 3 factors is also responsible for the closure of the ductus arteriosus?

Left sided pressure increases

Circulating oxygen increases

Prostaglandins decrease - also responsible for DA

If necessary, what medication can be given to help duct closure in newborns?

How soon should the foramen ovale and ductus arteriosus close functionally?

How long will it take for them to close by fibrosis?

Indomethacin (prostaglandin inhibitor)

First few hours of life

4-6 weeks

What is the fate of the foramen ovale?

What is the fate of the ductus arteriosus?

What is the fate of the ductus venosus?

Closes, or in 10% of people it persists as patent foramen ovale

Becomes ligamentum arteriosus, can also fail to close and be PDA

Becomes ligamentum venosus

The process of labour is relatively hypoxic, and so if the labour is prolonged or something goes wrong then what is likely to happen?

What makes this more likely to happen?

What will this be associated with and why?

The baby will become hypoxic

If the baby was unwell to start with

Acidosis, due to the production of lactic acid from anaerobic respiration

If the baby is acidotic at birth and has low oxygen, then this means that what won’t happen?

What are some factors which can cause this to happen?

The pulmonary resistance won’t drop and the vasculature will not develop in the right way

Sepsis, lung disease, cold stress

What happens when the pulmonary resistance fails to drop after delivery and the foetal circulation continues to exist?

Which foetal ducts are still working?

Unoxygenated blood gets sent where?

Oxygenated blood gets passed where?

Persistent pulmonary hypertension

Foramen ovale and ductus arteriosus

To the systemic circulation

To the pulmonary circulation

How can persistent pulmonary hypertension be diagnosed?

Pre and post ductal saturations

Right hand = high saturations

Left foot = low saturations

How is persistent pulmonary hypertension managed?

Ventilation (with inhaled nitric oxide)

Oxygen

Sedation

Inotropes

ECLS/ECMO

What is ECLS/ECMO?

What do you need to do before giving this?

What is the significance of persistent pulmonary hypertension caused by abnormal lung development?

A type of heart lung bypass which is used if the baby is too sick for other management

Lots of anticoagulation

No typical management options will work as this is irreversible

The lung bud comes out of where? At what stage of lung development do the different types of epithelium start to develop? As pregnancy continues, air sacs start to develop and only form alveoli when? Nearing term, babies start to produce what to help prepare for life outside the womb? What is the role of this? Who are deficient in this?

The GI tract The pseudoglandular stage 36 weeks Surfactant - they reduce surface tension to prevent the lungs from collapsing when the baby breathes out Premature babies- they need supplemented

What happens to cause transient tachypnoea of the newborn? How is this managed? What is the outcome of this?

There is retained foetal lung fluid due to impaired clearance methods Go to NICU for supplementary oxygen Generally good, but have to separate from mum which is not ideal

In the 3rd trimester, babies accumulate brown fat where? What is the purpose of this?

Between the scapulae and around internal organs Helps to maintain body temperature and to keep baby warm once it has been born

At the onset of labour, there is increased secretion of what by the foetus? What happens to the synthesis of lung fluid? Where does lung fluid get absorbed into? What is the advantage of vaginal delivery with regards to the lungs?

Catecholamines and cortisol It stops, and the baby gets ready to start reabsorbing it Into the lung interstitium, then lymph and then systemic circulation Squeezes fluid out of the lungs

In the first few seconds following delivery, the baby is blue and then starts to breathe. What should the pO2 be? What will the sats be initially? What will the sats be at around 10 minutes?

Between 3 and 5 60-70% 90%

The cord should only be clamped and cut immediately when? How long should this ideally be delayed by? What is the purpose in delaying this?

If the baby needs immediate resuscitation 30 secs - 1 min It causes CO2 to go up, and the bbay will feel cold which will help it start to breathe

Why are babies so prone to getting cold when they are born? Babies cannot shiver, but what can they do? What are the downsides to the above method?

They have a large surface area and are also wet Non-shivering thermogenesis: heat production as a result of breakdown of stored brown adipose tissue in response to catecholamines It can only occur from 12 hours, and if the baby is premature, they may not have enough brown or subcutaneous fat

What happens to levels of insulin and glycogen after birth? There is mobilisation of what for gluconeogenesis? Babies can use what as brain fuel? How long will it take for a baby's insulin level to go back to normal after delivery?

Insulin drops and glycogen increases Hepatic glycogen stores Ketones After the first few days

What are some reasons for neonatal hypoglycaemia?

Increased energy demands e.g. unwell, hypothermia Low glycogen stores e.g. small, premature Inappropriate insulin/glucagon ratio e.g. maternal diabetes Some drugs e.g. labetalol

What are the changes in the composition of breastmilk that take place? It is normal for babies to lose what amount of weight and when following delivery?

Colostrum, foremilk, hindmilk Lose up to 10% of their birth weight in the first few days and then they start to gain weight again

After birth, foetal haemoglobin becomes disadvantageous why? Haematopoiesis moves to where? Adult Hb is synthesised more slowly than foetal Hb is broken down which causes what? When does this peak?

Because there is an increase in 2,3-DPG which shifts the curve to the right Bone marrow Physiological anaemia - 8-10 weeks

When does physiological jaundice occur? Why does this occur? When may jaundice be pathological? How can it be treated if necessary?

Usually around 2-4 days Foetal Hb is broken down which causes a rise in circulating unconjugated bilirubin If very early or prolonged Exchange transfusion or phototherapy