Neonatal Physiology

Question 1

what is ductus arteriosus

Answer 1

connection between pumonary artery and aorta - to relieve circulatory load on lungs while RV strengthens

Question 2

what is ductus venonosus

Answer 2

branch from umbilical vein that merges with IVC - delivers oxygenated blood

Question 3

what is foramen ovale

Answer 3

hole between the atria of the heart

Question 4

what happens to more of the structures of the foetal heart by birth

Answer 4

they become ligaments/foramen ovale closes

Question 5

newborns have high/low O2 sats

Answer 5

low - 60-70%

Question 6

when does the heart start beating

Answer 6

4th week

Question 7

roughly, what is the blood pressure of a newborn baby <1hr old

Answer 7

70/44

Question 8

heart rate of a newborn

Answer 8

120-160bpm

Question 9

resp rate of a newborn

Answer 9

30-60/min

Question 10

what is defined as bradycardia in newborns

Answer 10

<100bpm

Question 11

physiological response to cold from baby

Answer 11

lipolysis of brown fat and heat production. Can’t shiver

Question 12

what is brown fat

Answer 12

fat designed to keep you warm when you break it down. Has many more mitochondria. innervated by sympathetic fibres. Everyone has it just babies have more

Question 13

tidal volume of baby

Answer 13

4-6ml/kg

Question 14

true/false - newborns have higher blood gas partial pressures

Answer 14

false - actually around normal

Question 15

pathophysiology of physiological jaundice

Answer 15

lots of RBC but an immature liver than can’t conjugate the bilirubin from breakdown fast enough –> build up of unconjugated bilirubin –> jaundice

Question 16

after how long does physiological jaundice become a concern

Answer 16

> 2 weeks

Question 17

main complication of newborn jaundice

Answer 17

kernicterus - unconjugated bilirubin crosses the BBB and deposits in brain. It’s neurotoxic

Question 18

presentation of kernicterus

Answer 18

encephalopathy, poor feeding, seizures

Question 19

late consequeuces of kernicterus

Answer 19

cerebral palsy, learning difficulties and sensorineural deafness

Question 20

how long does physiological jaundice take to develop

Answer 20

24 hours

Question 21

how long is it normal for babies not to pee for post-natally

Answer 21

24 hours

Question 22

true/false - babies have more insensible water loss

Answer 22

true - immature skin and breathing

Question 23

differences in neonatal kidneys

Answer 23

slower GFR
reduced Na reabsorption
less ability to concentrate or dilute urine

Question 24

why do babies sometimes lose up to 10% of their weight

Answer 24

because fluid is shifting from interstitial to intravascular space –> diuresis

Question 25

why do babies have a physiological anaemia

Answer 25

because the kidneys aren’t making enough erythropoietin yet

Question 26

timeline of anaemia

Answer 26

from birth till 8-12 weeks