1. Meconium aspiration syndrome

2. 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.

3. Risk factors Post-mature delivery Pre-eclampsia
3. placental insufficiency
4. smoking.
The main aetiology of MAS is : fetal hypoxic stress.

4. 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 .

5. 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.

6. complications Pneumothorax and pnemomediastinum.
PPHN ;persistant pulmonary hypertension of newborn.
Bronchopulmonary dysplasia

7. 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).