Neonatology Flashcards
When does the heart begin to develop?
End of 3rd week
Beats at end of 4th week
In foetal circulation where does oxygenated blood come from
From placenta via umbilical vein to ductus venosus- which shunts oxygenated blood to IVC bypassing the liver
Fucntion of foramen ovale?
Shunts blood from right atrium to left atrium
Function of patent dutus arteriosus
Shunts blood from pulmonary artery to aorta
Protects lungs against circulatory overload
Allows the right ventricle to strengthen
Carries low O2 saturated blood
Saturations SaO2 in foetal body
60-70%
Function of Ductus venosus
Connects the umbilical vein to the IVS
Normal blood pressure in a newborn
1hour age 70/44
1 day 70(+/-9)/42(+/-12)
3 days 77 (+/-12)/ 49 (+/-10)
Normal rr and hr in newbornes
RR- 30-60/min
HR- 120-160b/min
Tachycardia >160b/min
Bradycardia <100b/min
How do newborns thermoregulate
Lack shivering thermogenesis
Use Brown fat onnervated by sympathetic neurons
Cold stress leads to lipolysis and heat production
How do newborns lose heat
Radiation,
Convection,
Evaporation,
Conduction
Noninvasive ways to measure newborn breathing
Blood gas
PaCo2 (5-6kPa)
PaO2 (8-12kPa)
Trans-cutaneous pCO2/ O2 measurement
Invasive wats to measure newborn breathing
Capnography
Titdal volume 4-6ml/kg
Minute ventilation (tidal volume ml/kg x RR
Flow-volume loop
When does physiological jaundice appear in newborns
DOL 2-3
Disappears within DOL 7-10 or 21 in premature
10% breast fed jaundice at 30 DOL
What can high concentrations of bilirubin do to the brain?
Irreversible changes- kernicterus
How much weight is normal for a new born to lose and why?
10%
Due to:
- shift of interstitial fluid to intravascular
- Diuresis
Why is there increased loss of fluids in premature infants
Less fat in body Causing increased loss through kidney -slows GFR -Reduces Na reabsorption -Decreased ability to concentrate or dilute urine
Increased insensible water loss
-Via immature skin and breathing
Why does physiological anaemia of newborn occur
Rbc production is 10% of in uterus DOL 7
So babies are born with Hb 15-20g/l
And at week 10 Hb 11.4g/l
There is an increase production of erythropoetin
And at week 20 Hb is 12.0 g/l
Causes of anaemia in premature newborns
Reduced erythropoesis
Infection
Blood letting
