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Fifth stage
Pediatric
Lec4
.د
رياض
9/11/2016
Meconium aspiration syndrome
Definition
• It is a problem of aspiration of meconium (fetal stool) which
consist of bile and epithelial tissues and proteins of fetal tissue
that formed in the fetal intestine and normally passed in first 24
hr of birth.
• The meconium may passed intrauterine early before labour due
to stress condition of the fetus as hypoxia or infection leading to
intestinal stimulation and passage of meconium into the amniotic
fluid thereby staining it and shown as yellowish green stained
amnion during labour.
• About 5-25% of labour may have meconium stained amniotic
fluid, but only 10% get aspiration of meconium before delivery or
during it or immediately after delivery. Thin meconium and thick
meconium.
Risk factors:
1. Post-mature delivery
2. Pre-eclampsia
3. placental insufficiency
4. smoking.
The main aetiology of MAS is : fetal hypoxic stress.
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Pathophysiology
• MAS is mainly occurs in fullterm baby who exposed to
hypoxic stress inside the uterus pass meconium and
staining the amniotic fluid and the baby may develop
gasping movement leading to aspiration of amnion and
meconium either immediately before delivery or during
labour or the baby may be delivered and take breathing
with aspiration of the meconium that is in the mouth and
nose leading to signs and symptoms of M aspiration.
• Thick Meconium cause surfactant dysfunction and
chemical pneumonitis and cause small ball- check valve
bronchial obstruction leading hyperinlation and
atelectases of lung .
Clinical features:
• Baby may born depressed flat asphyxiated not breathing with
bradycardia and low Apgar score, acidotic with low ABG with
meconium stained umbilicus and nails and skin but still no
aspiration of meconium yet and the baby needs resuscitation ,
• or born with already aspiration of the meconium and vigorous
with tachypnea , grunting and hypoxia ,cyanosis, seen with low
SPO2 ,with wheezy chest and rales and fair to poor air entery. CXR
shows hyperinflated lungs and patches of atelectases depending
on the severity. Blood gas analysis will show respiratory acidosis
and hypoxia.
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Complications:
• Pneumothorax and pnemomediastinum.
• PPHN ;persistant pulmonary hypertension of newborn.
• Bronchopulmonary dysplasia
Treatment
• For flat depressed baby: immediate suction of meconium from the
mouth and throat with intubation and suction of thick meconium
below the larynx to prevent aspiration before the trial to stimulate
and or to initiate breathing.
• For vigorous baby who is breathing and who has aspirated the
meconium. Needs oxygen therapy and antibiotics and in severe
case may need connection to ventilator with surfactant therapy.
Even( NO) nitric oxide therapy used to vasodilate the pulmonary
arterioles in PPHN( persistent pulmonary hypertension of
newborn).