adaptation at birth

Question 1

what is the function of the placenta

Answer 1

maintain fetal homeostasis 
gas exchange nutrient transport to fetus 
waste product transport from fetus 
acid base balance 
hormone production 
transport of IgG

Question 2

name the 3 shunts present in the fetal circulation

Answer 2

ductus venosus
foramen ovale
ductus arteriosus

Question 3

what percentage of the fetal circulation goes via the lungs

Answer 3

7%

Question 4

where is ductus venosus

Answer 4

go from the left umbilical vein to the IVC

Question 5

where is the foramen ovale

Answer 5

in the septum between the left and right atria

Question 6

where is ductus arteriosus

Answer 6

connects the pulmonary trunk to the proximal descending aorta

Question 7

what physiological processes occur in the 3rd trimester in preparation of birth

Answer 7

surfactant production
accumulations of glycogen in liver, muscle and the heart
accumulation of brown fat between scapulae and around internal organs
accumulation of SC fat
swallowing amniotic fluid

Question 8

describe the circulatory transition that occurs after birth

Answer 8

pulmonary vascular resistance drops 
systemic vascular resistance rises 
oxygen tension rises 
circulating prostaglandins drop
ductus arteriosus constricts 
foramen ovale closes

Question 9

what causes the duct constriction after birth

Answer 9

increased pO2
decreased flow
decreased prostaglandins

Question 10

what happens to the shunts present in the fetal circulation

Answer 10

foramen ovale closes or persists as PFO
ductus arteriosus constricts to become ligament arteriosus or persists as PDA
ductus venosus constricts to become ligament teres

Question 11

what causes persistent pulmonary hypertension of the newborn

Answer 11

persistence of the fetal circulation

Question 12

management of PPHN

Answer 12

ventilation 
oxygen 
nitric oxide 
sedation 
inotropes 
ECLS (extra-corporeal life support)

Question 13

what sign is indicative of PPHN

Answer 13

O2 sats in right hand are higher than left foot

Question 14

what are the 4 methods of heat loss in a newborn

Answer 14

convection
conduction
evaporation
radiation

Question 15

what is the main source of heat production in newborns

Answer 15

non shivering thermogenesis
heat produced by breakdown of stored brown adipose tissue in response to catecholamines
not efficient in the first 12 hours of life
(additional peripheral vasoconstriction)

Question 16

why are preterm/SGA babies more prone to hypothermia

Answer 16

low stores of brown fat
little SC fat
larger surface area:volume

Question 17

how to prevent hypothermia

Answer 17

keep baby dry
hat 
skin to skin
blanket/clothes 
heated mattress 
incubator

Question 18

what changes in glucose homeostasis occur after birth

Answer 18

interruption of glucose supply from placenta
very little oral intake of milk
drop in insulin, increase in glycogen
mobilisation of hepatic glycogen stores for gluconeogeneis

Question 19

what metabolites are babies able to use as brain fuel

Answer 19

ketones

Question 20

what can cause hypoglycaemia in a newborn

Answer 20

increased energy demands (unwell/hypothermia)
low glycogen stores (small/premature)
inappropriate insulin:glucagon ratio (maternal DM, hyperinsulinism)

Question 21

which hormones are responsible for milk production and ejection

Answer 21

production = prolactin
ejection = oxytocin

Question 22

what causes physiological anaemia in newborns

Answer 22

adult Hb is synthesised more slowly than fetal Hb is broken down

Question 23

what causes physiological jaundice

Answer 23

liver enzyme pathways are present but immature
breakdown of fetal Hb
conjugating pathways are immature
rise in circulating unconjugated bilirubin

Question 24

when might jaundice be pathological in newborns

Answer 24

early (<24 hours) or prolonged jaundice may be pathological

Question 25

what are risk factors for adaptation problems

Answer 25

hypoxia/asphyxia during delivery 
particularly small or large babies 
premature babies 
some maternal illness and medications 
ill babies (sepsis, congenital anomalies)