Adaptation at Birth Flashcards

1
Q

what are the functions of the placenta?

A

foetal homeostasis

gas exchange

nutrient transport to and waste product transport from foetus

acid base balance

hormone production

transport of IgG

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2
Q

what are the 3 shunts of foetal circulation?

A

ductus venosus

foramen ovale

ductus arteriosus

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3
Q

what is the fate of the 3 shunts of foetal circulation - ductus venosus, foramen ovale and ductus arteriosus?

A

ductus venosus = becomes ligamentum teres

foramen ovale = closes (may persist as PFO in 10% - “hole in the heart”

ductus arteriosus = becomes ligamentous arteriosus

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4
Q

what changes occur during the 3rd trimester to prepare for birth at term?

A

surfactant production = lung function

accumulation of glycogen = liver, heart, muscle

accumulation of brown fat = between scapulae and around internal organs

accumulation of subcutaneous fat

swallowing amniotic fluid

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5
Q

what changes occur during labour and delivery to prepare for birth?

A

inceased catecholamines / cortisol = onset of labour

synthesis of lung fluid stops

vaginal delivery = squeezes lungs

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6
Q

what changes occur during the first seconds after birth of term delivery?

A

blue -> breathes -> cries -> pink

cord cut

circulatory transition

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7
Q

what specifically occurs during the circulatory transition which occurs in first few seconds of life?

A

pulmonary vascular resistance drops as systemic vascular resistance rises

oxygen tension rises

circulation prostaglandins drop

duct constricts - increase pO2, decreased flow and prostaglandins

foramen ovale closes

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8
Q

what is an example of the failure of cardiorespiratory adaptation in newborn and how is this treated?

A

persistent pulmonary hypertension of newborn (PPHN)

tx = ventilation, oxygen, nitric oxide, sedation, inotropes, ECLS

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9
Q

what changes occur in thermoregulation during the first few hours after birth?

A

main source of heat production is via 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

peripheral vasocontriction

newborn babies need help maintaining temperature

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10
Q

what changes occur in glucose homeostasis during first few hours of birth?

A

there is an interruption of the glucose supply from placenta and very little intake of milk resulting in an insulin drop and increase in glycogen

there is a mobilisation of hepatic glycogen stores for gluconeogenesis and an ability to use ketones as brain fuel

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11
Q

what changes occur in nutrition during the first few hours of life?

A

breast feeding

baby starts to suckle and the feedback loop causes an increase in supply and a change in breast milk composition (colostrum, foremilk and hindmilk)

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12
Q

what haematological changes occur after birth?

A

foetal haemoglobin becomes disadvantageous: an increase in 2,3 BPG moves curve to the right

haematopoiesis moves to the bone marrow but adult Hb is synthesised more slowly than foetal Hb is broken down (causes physiological anaemia, lowest point ie nadir is at 8-10 weeks)

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13
Q

what is the cause of physiological jaundice?

A

liver enzyme pathways (conjugating pathways) are present but immature

this combined with the breakdown of foetal haemoglobin causes a rise in circulating conjugated bilirubin

*generally, not harmful

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14
Q

all babies need help to maintain temperature but why are small for dates babies more prone to hypothermia?

A

low stores of brown fat

little subcutaneous fat

larger surface area:volume

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15
Q

how is hypotheramia treated in babies?

A

dry

hat

skin to skin

blanket / clothes

heated mattress

incubator

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16
Q

what can cause hypoglycaemia in babies?

A

increased energy demands (unwell, hypotheramia)

low glycogen stores (small, premature)

inappropriate insulin / glucagon ratio (maternal diabetes, hyperinsulinism)

some drugs

17
Q

how are babies with hypoglycaemia treated?

A

identify those at risk

feed effectively

keep warm

monitor

18
Q

babies are generally well prepared to adapt to extrauterine life but what babies are particularly at risk for adaptation problems?

A

hypoxia / asphyxia during delivery

particulary small or large babies

premature

some maternal illnesses and medications

ill babies (eg sepsis, congenital anomalies)