4. Pulmonary Disorders (RDS, TTN, BPD)

Question 1

What are the 6 classic signs of neonatal distress?

Answer 1

1. Nasal Flaring
2. Cyanosis
3. Expiratory Grunting
4. Tachypnea
5. Retractions
6. Hyperdynamic Precordium

Question 2

1. What is nasal flaring?

2. Why does this occur, and why is it seen more in neonates?

Answer 2

1. Dilatation of nostrils on inspiration
2. Occurs due to increased demand & attempt to decrease resistance, neonates are obligate nose breathers until 3-4 months

Question 3

1. How many g/dL of deoxygenated Hb is needed to cause cyanosis?
2. Does central or peripheral cyanosis pose more of a threat to the infant? Why?

Answer 3

1. 5 g/dL Hb will generate the dark blue colour

2. Central cyanosis is more of a threat because the baby needs O2 right away, peripheral is OK in first 24 hrs of life

Question 4

1. What is expiratory grunting?

2. Why would an infant grunt?

Answer 4

1. Exhalation against a partially closed glottis

2. To ↑ FRC, lungs are a bit collapsed, so baby grunts to ↑ lung volumes (creates back pressure)

Question 5

1. What is tachypnea in a newborn classified as?
2. What about in paediatrics?
3. Usual causes of tachypnea in a newborn?

Answer 5

1. RR > 60 bpm in newborns
2. Age dependent in peds
3. Hypoxemia, acidosis, anxiety, pain

Question 6

What breathing pattern is seen with poor lung compliance?

Answer 6

Rapid, shallow breathing

Question 7

1. What are chest retractions caused by?
2. What is observed when retractions are present, and why?
3. What are the 6 types of retractions?

Answer 7

1. Lung compliance is stiffer than chest wall compliance
2. Chest wall sucked in due to high negative pressure
3. -Sternal
   - Substernal
   - Supraclavicular
   - Suprasternal
   - Intercostal
   - Subcostal

Question 8

1. What is a hyperdynamic precordium?

2. What is it usually associated with?

Answer 8

1. ↑ motion visualized through the chest in the area of the heart
2. ↑ volume load on the heart secondary to L → R shunt through the PDA

Question 9

1. What is RDS?
2. What is incidence inversely related to?
3. Leading cause of ____?

Answer 9

1. Deficiency of pulmonary surfactant and immature lungs
2. Incidence inversely related to gestational age
3. Death among premature infants

Question 10

1. Causes of RDS?

2. Who does RDS affect more often & how much?

Answer 10

1. Surfactant deficiency or abnormality, prematurity, immature lungs, pulmonary hypoperfusion d/t hypoxia, idiopathic
2. Occurs more often in males and is usually more severe

Question 11

Pathophysiology of RDS

Answer 11

1. Surfactant deficiency (↑ surface tension)
2. ↓ lung compliance ( ↓ FRC, atelectasis)
3. V/Q mismatch w/ poor gas exchange (hypoxia, hypercarbia, acidosis)
4. Interstitial and intra-alveolar edema
5. Leakage of proteinaceous exudate and formation of hyaline membranes
6. Hypoxia induced pulmonary vasoconstriction (↑ PVR)
7. R → L shunt across patent FO and DA
8. Lung hypoperfusion → ischemia → decreased lung metabolism
9. Pulmonary surfactant reduced even further

Question 12

1. Secondary Surfactant deficiency may occur in infants with the following:
2. What can SSD lead to ?

Answer 12

1. Intrapartum asphyxia, pulmonary infections, pulmonary hemorrhage, meconium aspiration pneumonia, oxygen toxicity along w/ barotrauma or volutrauma
2. RDS

Question 13

Causes of ↓ surfactant production

Answer 13

Prematurity, familial predisposition, C section w/o labour, perinatal asphyxia, maternal diabetes, chorioamnionitis, cold stress

Question 14

Causes of ↑ surfactant production

Answer 14

Chronic intra-uterine stress, prolonged pPROM, maternal HTN, IUGR/SGA, Antenatal glucocorticoids, maternal use of narcotics, tocolytics

Question 15

What can be used to prevent/minimize RDS? (7 things)

Answer 15

1. Delay/prevent premature birth
2. Antenatal steroids
3. Early intervention (prevent cold stress, hypoglycaemia, hypoxemia) “warm, sweet, pink”
4. O2 therapy
5. Surfactant replacement
6. Nasal CPAP
7. Nasal NIV

Question 16

S&S of RDS?

Answer 16

Tachypnea, tachycardia, ↑ WOB (nasal flaring, grunting, retractions), cyanosis requiring O2, crackles, ↓ activity, apnea

Question 17

How is a diagnosis of RDS made? (ex. what is seen in the newborn/what can be done for confirmation of diagnoses?)

Answer 17

Clinical history (is baby premature?), clinical assessment, onset of progressive resp failure shortly after birth, CXR

Question 18

What is seen in an RDS CXR?

Answer 18

Low lung volumes, diffuse reticular granular pattern (frosted appearance), air bronchograms to the periphery

Question 19

What is the RDS clinical course? (4 features)

Answer 19

Resp. failure beginning at birth
Max severity by 24-48 hrs
Rapid improvement over 3-5 days
May progress to chronic changes = BPD

Question 20

What is the RDS management protocol?

Answer 20

Early CPAP, surfactant if indicated, extubate after surfactant if able and place on CPAP/NIPPV, avoid lung derecruitment, avoid hyperoxia

Question 21

What are the RDS mcvent strategies?

Answer 21

Avoid volutrauma, effective lung recruitment, extubate ASAP to NIV

Question 22

What are the RDS supportive care strategies?

Answer 22

Thermoregulation, fluid management, nutrition (breast milk, vitamin A, E

Question 23

What are the complications of RDS?

Answer 23

Air leaks, chronic changes leading to BPD, tracheal stenosis, reactive airway disease, ↑ risk of infection, intraventricular hemorrhage (IVH), retinopathy of prematurity (ROP), necrotizing enterocolitis (NEC)

Question 24

1. What is Transient Tachypnea of a Newborn (TTN)? What does this do to the lungs?
2. What is TTN also known as?
3. Who does it affect most?
4. When does it present? Resolve?

Answer 24

1. Fast and shallow breathing pattern, causes delayed reabsorption of fetal lung fluid (fluid in air spaces, wet lung)
2. RDS Type II
3. Term or near term infants
4. Presents at or shortly after birth, resolves within 24-48 hrs

Question 25

Physiology of Fetal Lung Fluid at Birth (3 stages!)

Answer 25

1. Labour → high circulating conc. of epi activates the switch w/i lungs from net secretion to net reabsorption 2. Vaginal squeeze of thorax contributes to very small portion of lung fluid re-absorption 3. Interstitial lung fluid moves into the pulmonary circulation (giving baby self transfusion of fluid) or drains via lung lymphatics

Question 26

1. Why is lung fluid retained in TTN? | 2. What does this cause? (3 things)

Answer 26

1. Incomplete absorption of pulmonary fetal fluid, ↓ removal of fluid by pulmonary lymphatics 2. Alveolar fluid, interstitial edema, compressed bronchial airways (from excessive A-C interstitial fluid, causes air trapping and alv. hyperinflation)

Question 27

Causes of TTN?

Answer 27

Full term pregnancy, delivery by C/S (esp. cold section, ↓ squeeze, ↓ catecholamines) precipitous vaginal deliveries (↓ squeeze, ↓ catecholamines), maternal analgesia/anesthesia during labour and delivery, intrauterine hypoxia, prematurity or SGA/IUGR babies

Question 28

S&S of TTN?

Answer 28

Tachypnea (as high as 120 bpm), rapid shallow breathing, nasal flaring, grunting, retractions, barrel shape chest from hyperinflation, wheezes and crackles may be present

Question 29

What do you see on a CXR of a baby with TTN?

Answer 29

Perihilar vascular markings, fluid in fissures (AP & lateral view), blunted costophrenic angles (small pleural effusions), hyperinflation (flattened diaphragms, bulging intercostals), patchy infiltrates

Question 30

How is TTN diagnosed?

Answer 30

History, CXR, clinical presentation, rule out other causes

Question 31

1. How is TTN treated? 2. What does NOT affect the clinical course of TTN? 3. When pneumonia is suspected, what meds are indicated?

Answer 31

1. Stabilization, monitoring, tests, oxygen therapy, CPAP, NIPPV, rarely intubation, fluid restriction is usually ordered until S&S resolve 2. Diuretics 3. Antibiotics

Question 32

What is BPD and who is it most common in? What are these patients treated with? What is BPD associated with?

Answer 32

1. Chronic Lung Disease , most common in preterm infants w/ RDS (lower gestational age = ↑ incidence, worse severity) 2. Mechanical ventilation, NIV, O2 therapy 3. Significant mortality, short/long term morbidity, including growth and neurodevelopment delay

Question 33

What are the 3 risk factors for BPD?

Answer 33

1. Prematurity, low BW 2. White boys 3. Genetic heritability

Question 34

What is the official BPD definition?

Answer 34

Need for oxygen based on GA and severity of disease, a trial on room air should be performed if infant on minimal O2 requirements to ensure need for O2 at time of assessment

Question 35

1. If baby is born < 32 wks, when should assessment for BPD be done? 2. What about >/= 32 wks?

Answer 35

1. < 32 wks: 36 wks PMA or discharge, whichever first | 2. >/= 32 wks: > 28 days but < 56 days postnatal age or discharge, whichever first

Question 36

How is a baby born < 32 wks old treated for mild, moderate, and severe BPD?

Answer 36

Treatment w/ O2 >21% for at LEAST 28 days plus... Mild: RA at 36 wks PMA/discharge Moderate: Need < 30% O2 at 36 wks PMA/discharge Severe: Need >/= 30% O2 and/or PPV/NCPAP at 36 wks PMA/discharge

Question 37

How is a baby born >/= 32 wks old treated for mild, moderate, and severe BPD?

Answer 37

Treatment w/ O2 >21% for at LEAST 28 days plus... Mild: RA by 56 days postnatal age/discharge Moderate: Need < 30% O2 at 56 days postnatal age/discharge Severe: Need >/= 30% O2 and/or PPV/NCPAP at 56 days postnatal age/discharge

Question 38

1. What does "Old BPD" (before surfactant and steroids) show as on a CXR? 2. Is this a more or less severe form of BPD? Is this commonly seen?

Answer 38

1. Cystic changes, heterogeneous aeration | 2. More severe form of BPD, not commonly seen now (only in severe cases)

Question 39

What does "New BPD" (after surfactant and steroids) show as on a CXR?

Answer 39

1. More uniform inflation and less fibrosis 2. Some parenchymal opacities, but more homogenous aeration and less cystic areas 3. Larger simplified alveoli and dysmorphic pulmonary vasculature

Question 40

1. The pathogenesis of BPD is ________. | 2. What could it include? (examples!)

Answer 40

1. Multifactorial (RDS → BPD) 2. Prematurity, resp. distress, mechanical ventilation, NIV, O2 supplementation/toxicity, infection & inflammation, pulmonary edema as result of/and PDA, fluid overloading, nutritional deficiencies, genetics