meconium aspiration syndrome
Pronunciation: meh-KOH-nee-um
Also written as: MAS — meconium aspiration syndrome
A respiratory condition caused by inhalation of meconium-stained amniotic fluid before or during delivery.
Full Definition
Meconium aspiration syndrome (MAS) occurs when a fetus or newborn inhales meconium-stained amniotic fluid, leading to airway obstruction, surfactant dysfunction, and chemical pneumonitis. Meconium passage in utero typically indicates fetal stress or post-term pregnancy. The thick, sticky consistency of meconium can cause complete or partial airway obstruction, leading to air trapping, pneumothorax, and persistent pulmonary hypertension. Clinical presentation includes respiratory distress, tachypnea, and barrel-shaped chest from air trapping. Treatment is supportive and may include mechanical ventilation, surfactant replacement, and in severe cases, ECMO support.
Usage
Usage note: Always specify that this occurs in term or post-term infants, not preterm.
In Context
- "The term infant developed meconium aspiration syndrome following thick meconium passage at delivery." — Neonatal admission note
- "Chest X-ray findings were consistent with MAS, showing bilateral patchy infiltrates and hyperinflation." — Radiology report