WEEK 1&2

Question 1

What is the definition of Meconium Aspiration Syndrome?

Answer 1

A syndrome associated with postmature infants, in which the infant inhales meconium particles, causing mild to severe respiratory distress.

Question 2

What is the definition of PERSISTENT PULMONARY HYPERTENSION OF THE NEWBORN (PPHN)

Answer 2

During the transition, pulmonary vascular resistance falls dramatically as the lungs assume the function of gas exchange. In some newborn infants, the normal decrease in pulmonary vascular tone does not occur

Question 3

What are the risk factors in MAS?

Answer 3

acute pulmonary vasoconstriction from acute perinatal events:
alveolar hypoxia,
hypoventilation from asphyxia,
hypothermia,
hypoglycemia

Question 4

What is the risk factors in PPHN?

Answer 4

-post-term delivery
-placental insufficiency
-meconium staining
-postnatal hypoxia
-hypoglycemia
-hypothermia
-polycythemia
-maternal prostaglandin
-bacterial pneumonia/sepsis
-diaphragmatic hernia

Question 5

What are the Etiologies for MAS?

Answer 5

-asphyxial episode
-meconium released
-gasping occurs

Question 6

What are the Etiologies for PPHN?

Answer 6

-acute pulmonary vasoconstriction from acute perinatal events:
alveolar hypoxia,
hypoventilation from asphyxia,
hypothermia,
hypoglycemia,
pneumonia
-idiopathic, normal CXR
-hypoplasia of the pulmonary vascular bed associated with congenital diaphragmatic hernia
-Oligohydramnios
-Congenital cystic adenomatoid malformation
-PGI2 vasodilator at birth

Question 7

What is the Pathophysiology for MAS?

Answer 7

-mechanical obstruction of the airways
-chemical pneumonitis
-inhibition of surfactant function
-inflammation
-excess fluid/edema
-air trapping
-ball-valve mechanism, air can get trapped past mucous plug but CANNOT escape
-effect of asphyxial damage to lung
-surfactant dysfunction
-Hyaline membranes
-superimposed pneumonia

Question 8

What is the Pathophysiology for PPHN?

Answer 8

-CYANOSIS
-INCREASED RIGHT VENTRICULAR AFTERLOAD
-marked PHTN that causes R to L shunting of blood through a patent foramen ovale and patent ductus arteriosus and hypoxemia.

Question 9

What are the causes for MAS?

Answer 9

Material from fetal bowel, undigested amniotic fluid, squamous epithelial cells and vernix is inhaled

Question 10

What are the causes for PPHN?

Answer 10

Combination of systemic hypotension, normal pulmonary arterial pressure and PDA can result in R-L sunting

Question 11

What is the frequency for MAS?

Answer 11

12.5% all deliveries
-200,000 neonates/year
-⅓ requiring intubation and MV

Question 12

What is the frequency for PPHN?

Answer 12

-1 in 1000 live births

Question 13

What is the mortality/morbidity in MAS?

Answer 13

4.9-37% mortality
-not associated with significant fetal asphyxia and has good prognosis

Question 14

What is the mortality/morbidity in PPHN?

Answer 14

-20-25% mortality with 15-20% neurologic impairment with new treatments
-survival is greater than 75%

Question 15

What are the clinical findings for MAS?

Answer 15

-severity related to the thickness of meconium (pea soup)
-tachypnea
-grunting
-retractions
-cyanosis (if left to right shunt)
-pneumothorax (11%)
-neuropathies (level of asphyxia)
-ABG: low PaCO2, normal pH

Question 16

What are the clinical findings for PPHN?

Answer 16

-cyanosis associated with tachypnea and respiratory distress
-cardiac examination may reveal a loud S2 or harsh systolic murmur
-ABG will have higher PaO2 values
-assess oxygen saturation on PREDUCTAL and POSTDUCTAL site to assess for right to left shunt at the level of the ductus arteriosus
-WBC to reveal underlying sepsis or pneumonia
-decreased platelet count

Question 17

What are the treatments for MAS?

Answer 17

-MV: slow RR, long I-time with moderate PEEP
-CPT
-Oxygen (PaO2 higher)
-antibiotics
- “combined approach” oropharyngeal suctioning after head delivery, laryngoscopy with straw suction
-extreme cases ECMO

Question 18

What are the treatments for PPHN?

Answer 18

-MV: low pressures (must avoid over-expansion)
-Wung et al reported “gentle ventilation”
-HFO
-aim for 50mmHg PaO2
-sedation often necessary to achieve adequate MV
-INO (vasodilation)
-surfactant
-ECMO is the last resort for cardiopulmonary bypass

Question 19

CXR findings for PPHN?

Answer 19

Enlarged heart and decrease in pulmonary vascularity