RHCN Lecture Notes Flashcards
What is 2,3-DPG
It is a compound that inhibits the switch from deoxy to oxyhaemoglobin (shifting curve right)
This is helpful because it means blood doesn’t steal oxygen from cells that need it. It means blood only associates with oxygen in the lungs
Why does HbF have a stronger affinity to oxygen than HbA
Because it has a weaker affinity with 2,3-DPG (left shift for baby)
Also because in pregnancy the mum makes more DPG (right shift for mum)
what vessels lead from fetus to placenta
Semi-deox blood
aorta –> internal iliac –> umbilical arteries
Describe fetal circulation
blood into umbilical vein over lift via ductus venosus into RA 2/3 through FO and LA --> LV aorta and away 1/3 to RV Into pul artery Most through ductus arteriosus into aorta Small amount into lungs
What happens to fetal circulation at birth
Pul vascular resistance drops Blood from RV goes into lungs Arteriosis starts shutting down Increased return to LA from pul veins shuts FO Ductus venosus constricts
How is fluid in the baby’s lungs removed
- physical squeezing and spluttering
- adrenaline mediates change in respiratory epithelium - switch from secretory to resorbing (via Na+ transport) into pulmonary vessels and lymph
What happens if pul vascular resistance remains high after birth
persistent fetal circulation
blood not getting to lungs (hypoxia)
cells not getting oxygen (lactic acidosis)
How do you manage persistent fetal circulation (3)
- high flow oxygen
- inhaled NO (vasodilator to try bring down pul vascular resistance)
- inotropes (to force blood into lungs)
What is differential cyanosis
When feet are cyanosed but hands are not.
Something that can happen in babies with a PDA.
Happens because the brachiocephalic trunk, left common carotid trunk and the left subclavian trunk is given off proximal to the PDA.
Remember that as a general rule:
L2R shunt = breathless
R2L shunt = blue
How do you manage PDA
indomethacin (NSAID)
Why and how do we give vitamin K to newborns
breast milk contains insufficient vitamin K - risk of haemorrhagic disease of the newborn
why do babies get neonatal jaundice (4)
- immature liver enzymes
- they have all the HbF to break down
- breast milk beta-gluronidase interferes
- they are polycythaemic in utero
when is baby jaundice not normal
<24hrs
>10 days (term)
>14 days (preterm)
Benefits to baby of breast feeding
From top to toe: neurocognitive development IQ is 8.3 better less ear infection less lung infection lower BP later in life less obesity less gastroenteritis 10x less NEC less diabetes less obesity less SID
benefits of mum to breastfeeding
less postpartum uterine bleeding cheaper allows bonding burns calories less breast, ovarian, uterine cancer less osteoporosis less arthritis less heart disease
at what point in feeding session is fat content highest
end (because fat globules accumulate in lobules not in ducts in between feeds)
disadvantages of breast feeding
slower growth of baby
poorer bone mineralisation (less vit D compared to formula)
APGAR score
check elsewhere
preterm birth =
<37w
low birth weight
v low birth weight
extreme low birth weight
low = <2.5kg
v low = <1.5
extreme low = <1
perinatal vs neonatal death
perinatal = stillbirths + within 7 days neonatal = 7-28 days
what happens at 24 weeks in gestation in terms of lungs
You get canaiculi –> saccules in lungs
You get surfactant
What is apnoea of prematurity and Mx
When baby’s brain doesn’t tell it to breathe properly
Mx = caffeine (+ resp support if needed)
Acute and later in life worry with a PDA
Acute = heart failure Later = chronic lung disease