Adaption at birth** Flashcards
what does the fetal lung do in utero
produce lung fluid which contributes to amniotic fluid
how mania veins and arteries does the placenta heave coming baby
1 umbilical vein
2 arteries
how many shunts are there in the fetus and what are they
3
ductus arteriosis
ductus venousus
foramen ovale
what does DV do
allows oxygenated blood from the placenta to bypass the liver
leads blood into IVC
what does DA do
allows most of the blood from the right ventricle to bypass the fetus’s fluid-filled non-functioning lungs
most of the blood goes into the systemic circulation
what does the foramen ovale do
and what is it
flat opening in the left ventricle
shunts highly oxygenated blood from right atrium to left atrium
what happens to DA after birth
ligamentum arteriorsis
what happens to DV after birth
ligamentum teres
what happens to the foramen ovale after birth
usually closes
what happens in preparation of birth in terms of lungs
surfactant production
in preterm babies mums are given IV dexa to promote surfactant production to reduce the chances of neonatal respiratory distress syndrome
what happens in preparation of birth in terms of glucose
accumulation of glycogen to prepare for he disconnection from the placenta
this is in the heart, muscle, liver
also allows them to deal with the stress of labour
what happens in preparation of birth in terms of fat
accumulation of brown fat between scapulae and around internal organs to keep them warm
accumulation of subcut fat as well
what hormones are increased in labour and delivery
catecholamines and cortisol
colour of the baby when it first comes out - and what happens after it
comes out blue takes a deep breath cries goes pinker cord gets cut
lung aeration when the baby first comes out - steps
cold when baby comes out
baby becomes more hypoxic because placenta disconnected
CO2 levels rise allowing them to breathe by crying
breathing pushes the pulmonary fluid out of the lungs into the lymphatic tissue
what happens during circulatory transition what resistance drops and why which leads to what what resistant rises which leads to the closing of what
pulmonary resistance drops because baby starts to breathe
blood starts to circulate through the lungs and needs all of the circulation to go through and not just 7%
systemic vascular resistance rises because the cord is cut leading to oxygen tension rising
left sided pressure increases leading to the closure of FO
what things lead to the cut constricting (FO closing)
pressure imbalance
increased oxygen
decrease prostaglandins due to disconnected placenta
when might the duct tissue not constrict
what can this lead to
what is the treatment
in preterm babies as the tissue is not mature enough to close properly
patent ductus arteriosis
NSAIDs as this decreases the level of prostaglandins
what is persistent pulmonary tension of the newborn
if the pulmonary vascular resistance fails to drop
blood will still cross from right to left via the foramen ovale
baby will stay blue
what are the causes of persistent pulmonary tension of the newborn
sick, septic, asphyxiated, unwell, idiopathic
dx of persistent pulmonary hypertension
sats probe on pre ductal such as the right arm and on post ductal feet
usually 20% difference
treatment of persistent pulmonary hypertension of the newborn
ventilation with a tube
oxygen
sedation
warm
inotropes if theres any myocardial dysfunction
nitric acid - if the above does work - vasodilator for the lungs
ECLS - last line - take the blood out of the baby and oxygenate it then put it back in
how long does transient tachypnoea last
who does it occur in and why
benign, self limiting, resolves in around 24 hours
C section babies - they take longer to reabsorb all the lung fluid
why do babies lose a lot of heat when they are born and through which ways do they lose heat
large surface area
wet when born
conduction, convection, evaporation, radiation
how to keep the baby warm
hat, blanket, skin-to-skin with the mum, heated mattress, incubator
which babies get hypothermia and what can this lead to
premature
babies that are small
predisposes to other problems
what does little oral intake of milk in the first few hours of life lead to in the baby
a drop in insulin and an increase in glycogen and use of hepatic glycogen stores
how are babies adapted to dealing with hypoglycaemia
use ketones as brain fuel
which babies get hypos
babies who are unwell due to increased energy demands
maternal DM/hyperinsulinaemia
small/premature babies have low glycogen stores
drugs in the mother such as labetalol
what does breast feeding reduce the risk of in the mum
why is breast feeding good for the baby
reduced risk of ovarian and breast cancer
transfer of immunoglobulins to the baby[colesterum]
what % weight loss does a baby have to lose to be at risk
and at risk of what
10%
risk of dehydration and become hypernatraemic
what is the difference between fetal haemoglobin and adult haemoglobin
fetal Hb has a higher affinity for oxygen
what happens to fetal hb when the baby is born
it is broken down and replaced by adult haemoglobin
how long is it normal to be anaemic in babies and why
8-10 weeks
as adult hb production catches up
why can unconjugated jaundice occur in babies
due to breakdown of RBCs
very high levels of bilirubin can lead to what
bilirubin encephalopathy
when is jaundice bad
<24 hours
prolonged - longer than 14 days in term and longer than 21 days in preterm
