TTNB

Question 1

What is TTNB?

Answer 1

A benign/temp condition caused by delayed fetal lung fluid absorption. Leads to:

• Edema
• Delayed shunt closure
• Difficulty oxygenating = Increased WOB

Question 2

Why does TTNB cause difficulty with oxygenation and ventilation?

Answer 2

Impairs compliance and gas exchange (via increased fluid in the lungs)

• Congested pulmonary capillaries could compress bronchial pathways are consolidate = increased resistance = increased WOB
• interstitial edema could also cause compression of bronchial pathways

Question 3

How does TTNB affect lung volumes if compliance is impaired?

Answer 3

Alveoli can’t fully collapse during exhalation which causes increased RV, when fluid fills the alveoli and interstitial spaces the lungs become less compliant bc they are harder to close and probably open

• Increases residual volume = decreased tidal volumes (potentially)
• Vt thus drops bc there is less available surface area for gas exchange

Question 4

Risk factors for TTNB

Answer 4

• C section
• maternal analgesia
• baby boy
• prolonged labor

Question 5

What are the main structural changes that occur with TTNB?

Answer 5

Pulmonary lymphatics don’t absorb adequate fetal lung fluid post birth leading to

• Dilution of surfactant
• consolidation of alveoli (decrease C, increased R)
• pulmonary capillaries become congested
• Interstitial edemas

Question 6

What are the main pathological affects of TTNB?

Answer 6

Impaired compliance and gas exchange due to:

• Air trapping and alveolar hyperinflation bc of excessive fluid in the lungs (increases R, Decreases C)
• Compressed bronchial airways caused by congested capillaries (increases R)

Question 7

How does TTNB manifest?

Answer 7

Typical cyanosis picture, high RR with shallow breathing (>140)

• Increased WOB (nasal flaring, chest retractions, grunting)
• Increased O2 demand

Question 8

What is the typical timeline for TTNB?

Answer 8

Appears hours after birth, usually begins to resolve in 42-72 hours

Question 9

Typical CxR characteristics for TTNB

Answer 9

Normal at the beginning will develop:

• Perihilar streaking
• Hyperinflation
• Depressed diaphragm
• Fluid in minor fissure/pleural space

Question 10

TTNB management

Answer 10

Supportive care (O2 for demand and CPAP to prevent further edema)

• Diuretics (reduce edema)
• SxN
• Hyperoxic test to rule out cyanotic heart disease