meconium aspiration syndrome
Respiratory distress in newborns caused by aspiration of meconium-stained amniotic fluid during delivery.
Full Definition
Meconium aspiration syndrome (MAS) occurs when a newborn inhales meconium-stained amniotic fluid during delivery, leading to airway obstruction, surfactant inactivation, and chemical pneumonitis. The condition is associated with fetal distress and post-term pregnancies. MAS can cause severe respiratory failure due to ventilation-perfusion mismatch, air trapping, and persistent pulmonary hypertension of the newborn (PPHN). Management includes respiratory support, sometimes requiring high-frequency ventilation or ECMO for severe cases. Prevention involves appropriate obstetric management and avoiding routine suctioning, which may paradoxically worsen outcomes.
Usage
Usage note: MAS acceptable after first use. Often associated with PPHN, but distinct conditions.
In Context
- "The term infant developed severe meconium aspiration syndrome requiring intubation and high-frequency ventilation." — NICU admission note
- "MAS complicated by persistent pulmonary hypertension necessitated ECMO support." — Neonatology consultation