Fetal Adaptations Flashcards

1
Q

t/f in utero, fetal core temp is >0.5 C than the mother’s temp

A

true

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2
Q

how is heat lost in newborns

A

conduction
convection
evaporation
radiation

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3
Q

how do newborns produce heat

A

lipolysis of brown adipose tissue

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4
Q

why are pre-term babies more at risk for hypothermia

A

immature skin
greater surface area to body weight ratio
decreased brown adipose stores`

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5
Q

t/f preterm infants will have smooth skin

A

f, transparent and thin skin

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6
Q

methods to produce heat

A

drying the infant, radiant warmers, plastic wrap, kangaroo care

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7
Q

optimal environmental temperature for minimal heat loss nd oxygen consumption

A

36.5-37 C

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8
Q

t/f the breathing movements fetuses do in utero are for gas exchange

A

false, these are intermittent and not for gas exchange

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9
Q

factors leading to adequate lung function

A

airway patency
functional lung development
maturity of respiratory control

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10
Q

during labor, there is an increase in ____ that enhances lung fluid absorption and triggers ___

A

increase in catecholamines, vasopressin, prolactin, and glucocorticoids

triggers change in epithelia from chloride secretory to sodium resorptive

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11
Q

what does surfactant do

A

enhances aeration of gas free lungs by reducing surface tension, lowering pressure required to open alveoli

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12
Q

t/f air entry into the lungs displaces the fluid causing an increase in hydrostatic pressure and decrease in pulmonary blood flow

A

false, decrease in hydrostatic pressure and increase in pulmonary blood flow

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13
Q

how is spontaneous breathing after birth maintained

A

activation of chemoreceptors
decrease in placental hormones that inhibit respiration
presence of natural environmental stimulation

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14
Q

most critical reason for apnea

A

acidosis secondary to compromised fetal circulation

others: narcotics, anesthetics, mg

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15
Q

how to manage fetal apnea

A
  • primary apnea: reverse by stimulation

- secondary apnea: assisted ventilation

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16
Q

t/f frc is lowest in immature infants due to decreased alveolar number

A

true

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17
Q

timeline for surfactant production

A

20 aog: high conc but not on surface
28-32 w: in amniotic fluid
35 w: mature levels

18
Q

incidence of rds

A

60-80% <28 aog
15-30% 32-36 aog
rare at >37 aog

19
Q

three structures in fetal circulation

A

ductus venosus = uv to ivc
fo = bypass right to left atrium
da = connects pulmonary artery to aorta

20
Q

in utero circulation

A

go to trans

21
Q

rv to lv ratio and total fetal cardiac output

A

rv to lv ratio 1.3:1

total fetal cardiac output 450 ml/kg/min

22
Q

expansion of lungs and incresed arterial po2 leads to

A

decreased pulmonary vascular resistance and increased systemic vascular resistance

23
Q

ductus venosus closure

A

closed by removal of placenta in 1-3 hrs

24
Q

ductus arteriosus closure

A

closed by high arterial po2 in 10-15 hrs

25
Q

foramen ovale closure

A

closed by increased LA and LV pressure by 3rd month of life

26
Q

t/f the fall in prostaglandin causes the DA and UA to close

A

true

27
Q

t/f newborns at rest have a low oxygen consumption which is associated with high cardiac output

A

false, high oxygen consumption, high cardiac output, high hr

28
Q

t/f increased fetal hemoglobin requires increased co

A

true

29
Q

average central aortic pressure in neonates

A

75/50 mmhg

30
Q

cardiac output changes

A

350 ml/kg/min -> 150 ml/kg/min in first 2 months

75 ml/kg/min in adult levels

31
Q

conditions that cause hypoxia

A

asphyxia
meconium aspiration (postterm)
pneumonia
extreme prematurity

32
Q

fetal hemoglobin is present until

A

3 mos

33
Q

high affinity of hbf means

A

less oxygen is available for the tissues = clingy to the o2

34
Q

when is physiologic decrease of hemoglobin noticed

A

8-12 w in term, 6 w in preterm

35
Q

t/f the infant brain lacks cerebral autoregulation

A

true, makes infants predisposed to intraventricular hemorrhage

36
Q

consequence of weak bbb

A

medications easliy permeate central venous system = increased sensitivity to lipid soluble drugs

37
Q

spinal cord and dural sac ends at

A

spinal cors: l3 (adult l1)

dural sac s4 (adult s2)

38
Q

t/f there is a surge of tsh immediately after birth and increase in t3/4

A

true

39
Q

factors leading to ger

A

decreased gastric emptying and decreased lower esophageal tone

40
Q

factors leading to high urine output

A

unable to concentrate urine due to lack of kidney’s tubular function

41
Q

physiologic weight loss due to high urine output

A

10% of baby’s birth weight