Fetal development/Post natal compcliations

Question 1

What problems would you expect in a premature infant 24 weeks of gestation?

Answer 1

1. RDS or BPD; lack surfactant to keep alveoli open for gas exchange and potential for lung damage
2. Hypotension: PDA may stay open = abnormal blood flow between aorta and pulmonary artery
3. Intraventricular hemorrhage: brain is literally fragile
4. Apnea of prematurity (hypoxia caused by immature resp control center)

Question 2

What are factors that could affect fetal development?

Answer 2

1. Fetal lung fluid
2. Teratogens
3. Maternal-fetal gas exchange
4. Amniotic fluid

Question 3

Why is fetal lung fluid important to fetal development?

Answer 3

Promotes growth, maturation, and functional development of lung structures.

• Fetus breathe liquid than transition to air

Question 4

What happens if babes fail to transition to air or fetal fluid remains in the airway?

Answer 4

1. Failure to transition to air could mean and lack of fetal fluid during development which could cause pulmonary hypoplasia
2. Failure to clear liquid during transition leads to TTNB

Question 5

What develops at each stage of fetal development?

Answer 5

1. Embryonic: trachea + major bronchi
2. Pseudo glandular: Conducting airways/tracheobronchial tree
3. Canalicular: Vascular bed + framework of acinus
4. Saccular: Terminal airways/saccule framework and maturation of surfactant
5. Alveolar: Alveoli are developed

Question 6

What weeks do each of the phases of development occur?

Answer 6

1. Embryonic: 0-6
2. Pseudo glandular: 6-16
3. Canalicular: 17-26
4. Saccular: 26-36
5. Alveolar: 36-40

Question 7

What week are fetus viable?

Answer 7

24-26 bc enough proliferation of immature surfactant is created

• aka gas exchange can occur (not great)
• surfactant appears at 20 weeks

Question 8

Factors that affect fetal development

Answer 8

1. Teratogens
2. Fetal lung fluid
3. Maternal fetal gas exchange
4. Amniotic fluid

Question 9

What could happen if fetal development is halted during the embryonic phase

Answer 9

1. Choanal atresia
2. Pulmonary hypoplasia
3. Congenital diaphragmatic hernia

Question 10

What happens if cilia dysfunction/impairment occurs during development

Answer 10

Impairs mucous transport increasing risk of infection

• Cilia development begins in week 13

Question 11

Maternal-fetal gas exchange route/develpment?

Answer 11

1. Placenta (poor)
2. Chorionic villi
3. Umbilical cord

Question 12

What is the limiting factor in maternal-fetal gas exchange that leads to fetal hypoxia?

Answer 12

Any factor that decreases uterine or fetal blood flow

Question 13

3 sections of umbilical cord?

Answer 13

1. 2 umbilical arteries
2. 1 umbilical vein
3. Wharton jelly (cushion)

Question 14

Umbilical cord vs Umbilical vein blood flow/content?

Answer 14

Opposite of adults

1. 2 Umbilical arteries carry deoxygenated blood to the placenta for reoxygenation
2. 1 umbilical vein carries oxygenated blood to the fetus

Question 15

Why is persistent fetal circulation (PRF) problematic?

Answer 15

Failure to transition after birth has the risk of hypoxia and worsening oxygen deprivation.

• Alveoli and blood vessels are underdeveloped meaning they cannot oxygenate or ventilate
• Can lead to pulmonary hypertension

Question 16

Why is pulmonary hypertension a problem?

Answer 16

Increased PVR can strain the heart (RV) reducing overall oxygenation meaning hypoxia

Question 17

When does brown fat develop?

Answer 17

Week 26; and continues until 3-5 weeks after birth

Question 18

What is the physiological response for heat preservation by babes if they cannot support themselves mechanically (shivering) or chemically (brown fat)?

Answer 18

Peripheral Vasoconstriction to prevent blood from reaching the skin where heat loss occurs

Question 19

What are signs of hypothermia/cold stress?

Answer 19

• Peripheral vasoconstriction
• tachypnea
• mottled skin

Question 20

What is the L/S ratio indicative of?

Answer 20

Lung maturation

• Acquired via amniotic fluid via amniocentesis

Question 21

In a fetus, are right or left sided heart pressures higher?

• why?

Answer 21

Right bc of hypoxic pulmonary vasoconstriction secondary to low PO2 values with nonaerated lungs

Question 22

In a fetus, are right or left sided heart pressures lower?

• why?

Answer 22

Left in fetus bc of low resistance from the placenta

Question 23

Transition to neonatal circulation occurs because of what 3 factors?

Answer 23

1. Clamping of the umbilical cord
2. Initiation of the first breath
3. Closure of fetal shunts

Question 24

Pulmonary vasodilators for neos?

Answer 24

iNO and oxygen are the big ones.

• Sildenafil is also used for ppHn/high PVR