MECONIUM ASPIRATION SYNDROME

Question 1

What is Meconium

Answer 1

It is the first intestinal discharge from newborns, a viscous, dark-green substance.

Question 2

Meconium aspiration syndrome

Answer 2

Breathing in a mixture of meconium and amniotic fluid into the lungs around the time of delivery (before, during or after birth)

Question 3

Components of meconium

Answer 3

intestinal epithelial cells
Lanugo (hair)
Mucus
Bile salts
Amniotic fluid
Water
Desquamated skin

Question 4

Classifications of MAS

Answer 4

Grade 1
Grade 2
Grade 3

Question 5

Causes of Meconium passage in utero

Answer 5

Any distress;
Maternal hypertension
Preeclampsia
Placental insufficiency
Fetal Hypoxia
Acidosis
Oligohydramnios
Drug Abuse
Infection

Question 6

Pathophysiolgy of Meconium passage

Answer 6

In utero meconium passage results from neural stimulation of a maturing gastrointestinal (GI) tract, usually due to fetal hypoxic stress.

Occurs in term and postterm babies (>39wks)

Question 7

Effects of meconium on amniotic fluid

Answer 7

1) Reduce antibacterial properties of amniotic fluid
2) Irritating to fetal skin
3) Perinatal aspiration of meconium (MAS)

Question 8

Hypoxia Mechanism of MAS

Answer 8

1) AIRWAY OBSTRUCTION
2) SURFACTANT DYSFUNCTION (Deactivation & secretory inhibition)
3) CHEMICAL PNEUMONITIS
4) NEWBORN PERSISTENT PULMONARY HYPERTENSION (due to thickened pulmonary vessels)

Question 9

What is Air trapping

Question 10

What is ball-valve effect

Question 11

Clinical manifestations of MAS

Answer 11

Tachypnea
Cyanosis
Rales & rhonchi upon auscultation
End Expiratory grunting
Nasal flaring
Intercostal recession
Barrel chest due to air trapping
Yellow-green stained fingernails, umbilical cord & skin
Meconium staining in larynx & trachea seen upon intubation

Question 12

Diagnosis

Answer 12

1) History of meconium noted at/ before delivery (meconium in amniotic fluid)
2) Presence of neonatal Respiratory distress
3) CXR
4) Blood culture for infections
5) ABG

Question 13

What are the CXR findings for MAS

Answer 13

Hyperinflation
Consolidation
Diffuse asymmetrical patchy infiltrates
Pneumothorax

Question 14

Treatment & Management

Answer 14

1) vigorous baby (normal respiratory effort & muscle tone), receive the initial steps of newborn care. A bulb syringe can be used to gently clear secretions from the nose and mouth.

2) Respiratory distressed baby: place the baby on a radiant warmer, use bulb syringe to clear secretions, and proceed with the normal steps of newborn resuscitation (ie, warming, repositioning the head, drying, and stimulating).
If after these initial, the baby is still not breathing/ HR<100bpm, tracheal intubation under direct laryngoscopy & intratracheal suctioning

3) minimal handling if infant to avoid agitation that could worsen the condition

4) An umbilical artery catheter should be inserted to monitor blood pH and blood gases without agitating the infant.

5) Surfactant therapy is commonly used to replace displaced or inactivated surfactant and as a detergent to remove meconium

6) For PPHN pulmonary vasodilator such as inhaled nitric oxide, phosphodiesterase inhibitors & oxygen may be used

7) For severe hypoxia CPAP or ECMO may be used but cautiously