Physiology of Neonates Flashcards
What carries oxygenated blood to the baby [2]
What carries deoxygenated blood [2]
Umbilical vein
Carries O2 blood from placenta to foetus
Umbilical artery x2 - from bifurcation of aorta - placenta
What is the ductus venous and what type of blood
Foetal blood vessel connecting umbilical vein from placenta to IVC of baby
Mostly oxygenated
Liver gets most oxygenated blood as first organ where umbilical vein goes
What is the foramen ovale
Hole connecting RA-LA
Bypass immature lungs
What is the ductus arteriosus
Allows blood flow from Pulmonary artery to aorta without travelling through foetal inadequate lungs
If it doesn’t close blood flows from aorta -> Pa
What does ductus arteriosus allow
RV to strengthen
Protect lungs from circulatory overload
What does ductus arteriosus carry
Low oxygen saturated blood
What is the saturation in a foetus
60-70%
When does the cardiovascular system start to develop [2]
End of third week
Heart beats at 4th week
What happens at first breath [4]
- Move fluids out of lungs and arteries in lungs open
- Foramen ovale closes - hard to open after 14 days
- PDA stays open 1-2 days
- Others all become ligaments
What are vital signs of newborn
BP, RR, HR
What is considered tachycardia and bradycardia in a newborn?
BP 70/40ish RR - 30-60 HR- 120-160 Tachy >160 Brady <100
How do new born babies thermoregulate [3]
- Lack shivering thermogenesis
- Rely on metabolic heat
- Brown fat innervated by sympathetic nervous system
If premature lack brown fat
What are the 4 ways to lose heat [4]
Radiation - to colder
Convection - moving air
Evaporation - to water
Conduction - to surface you touch
How do you assess newborn breathing non-invasively [3]
- Clinical - RR
- Blood gas determination - take capillary blood + analyser
- Trans-cutaneous PCO2,O2
What should the PaCo2 and PaO2 be in a newborn
PaCO2 - 5-6
PaO2 - 8-12
How do you assess breathing invasively [2]
Capnography - monitors PaCO2 in intubation
Physiological jaundice
Day 2-3 and disappears in 7-10 days or three weeks in prem
Breast feed increases duration
Fluid balance in term newborn
Will newborns require fluid support usually?
Urea and creatinine levels off in first 24h, is this normal?
Newborn not passing urine in first 24h, intervention?
- Should be able to maintain fluid and electrolyte balance
- U+E may be off first 24 hours as mother may have had IV fluids
- Normal not to pass urine for 24 hours
- Weight loss up to 10% is normal
Fluid balance in premature babies - what to consider in their physiology? [3]
Less fat
Increased loss through kidney
Increased insensible water loss
Why is there increased loss through kidney in premature babies [3]
Slower GFR
Reduced Na reabsorption
Decreased ability to concentrate or dilute urine
Physiological anaemia
Reduced RBC production when born then increases
What is physiological of anaemia in prematurity [3]
Reduced erythropoiesis
Blood letting
Infections
How do you treat physiological anaemia
Give iron at 28 days if premature
What do you do if low Hb
Look at reticulocyte count to see if haemolytic
Why are bloods not accurate 1st 24 hours
Affected by mother e.g. if had IV fluid
So repeat
