Fetal Adaptations

Question 1

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

Answer 1

true

Question 2

how is heat lost in newborns

Answer 2

conduction
convection
evaporation
radiation

Question 3

how do newborns produce heat

Answer 3

lipolysis of brown adipose tissue

Question 4

why are pre-term babies more at risk for hypothermia

Answer 4

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

Question 5

t/f preterm infants will have smooth skin

Answer 5

f, transparent and thin skin

Question 6

methods to produce heat

Answer 6

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

Question 7

optimal environmental temperature for minimal heat loss nd oxygen consumption

Answer 7

36.5-37 C

Question 8

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

Answer 8

false, these are intermittent and not for gas exchange

Question 9

factors leading to adequate lung function

Answer 9

airway patency
functional lung development
maturity of respiratory control

Question 10

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

Answer 10

increase in catecholamines, vasopressin, prolactin, and glucocorticoids

triggers change in epithelia from chloride secretory to sodium resorptive

Question 11

what does surfactant do

Answer 11

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

Question 12

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

Answer 12

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

Question 13

how is spontaneous breathing after birth maintained

Answer 13

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

Question 14

most critical reason for apnea

Answer 14

acidosis secondary to compromised fetal circulation

others: narcotics, anesthetics, mg

Question 15

how to manage fetal apnea

Answer 15

• primary apnea: reverse by stimulation

- secondary apnea: assisted ventilation

Question 16

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

Answer 16

true

Question 17

timeline for surfactant production

Answer 17

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

Question 18

incidence of rds

Answer 18

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

Question 19

three structures in fetal circulation

Answer 19

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

Question 20

in utero circulation

Answer 20

go to trans

Question 21

rv to lv ratio and total fetal cardiac output

Answer 21

rv to lv ratio 1.3:1

total fetal cardiac output 450 ml/kg/min

Question 22

expansion of lungs and incresed arterial po2 leads to

Answer 22

decreased pulmonary vascular resistance and increased systemic vascular resistance

Question 23

ductus venosus closure

Answer 23

closed by removal of placenta in 1-3 hrs

Question 24

ductus arteriosus closure

Answer 24

closed by high arterial po2 in 10-15 hrs

Question 25

foramen ovale closure

Answer 25

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

Question 26

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

Answer 26

true

Question 27

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

Answer 27

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

Question 28

t/f increased fetal hemoglobin requires increased co

Answer 28

true

Question 29

average central aortic pressure in neonates

Answer 29

75/50 mmhg

Question 30

cardiac output changes

Answer 30

350 ml/kg/min -> 150 ml/kg/min in first 2 months | 75 ml/kg/min in adult levels

Question 31

conditions that cause hypoxia

Answer 31

asphyxia meconium aspiration (postterm) pneumonia extreme prematurity

Question 32

fetal hemoglobin is present until

Answer 32

3 mos

Question 33

high affinity of hbf means

Answer 33

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

Question 34

when is physiologic decrease of hemoglobin noticed

Answer 34

8-12 w in term, 6 w in preterm

Question 35

t/f the infant brain lacks cerebral autoregulation

Answer 35

true, makes infants predisposed to intraventricular hemorrhage

Question 36

consequence of weak bbb

Answer 36

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

Question 37

spinal cord and dural sac ends at

Answer 37

spinal cors: l3 (adult l1) | dural sac s4 (adult s2)

Question 38

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

Answer 38

true

Question 39

factors leading to ger

Answer 39

decreased gastric emptying and decreased lower esophageal tone

Question 40

factors leading to high urine output

Answer 40

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

Question 41

physiologic weight loss due to high urine output

Answer 41

10% of baby's birth weight