NCLEX Review Guide: Meconium Aspiration Syndrome

Understanding Meconium Aspiration Syndrome (MAS)

• Meconium Aspiration Syndrome (MAS) occurs when a newborn inhales meconium-stained amniotic fluid before, during, or after birth, leading to respiratory distress and potential complications.
• Meconium passage in utero typically indicates fetal hypoxia or stress, causing relaxation of the anal sphincter and passage of the first stool.
• Aspiration can occur antepartum (in utero) or during delivery, with thick meconium being more dangerous than thin meconium.

Signs and Symptoms

• Respiratory distress including tachypnea, retractions, nasal flaring, and cyanosis appearing within hours of birth.
• Barrel-shaped chest due to air trapping, with prolonged expiratory phase and possible pneumothorax development.
• Meconium staining of skin, nails, and umbilical cord indicates prolonged exposure to meconium-stained fluid.

Immediate Care

1. Do NOT stimulate crying if meconium is present and infant is not vigorous - avoid suctioning mouth and nose at perineum.
2. For non-vigorous infants: Perform immediate intubation and tracheal suctioning before initiating positive pressure ventilation.
3. Provide continuous oxygen monitoring and respiratory support as needed, including mechanical ventilation if severe.
4. Monitor for complications including pneumothorax, persistent pulmonary hypertension, and secondary infections.

Common Pitfalls

• Never suction vigorous infants - current guidelines emphasize this change from previous practice.
• Don't confuse MAS with RDS - MAS occurs in term infants, RDS in preterm infants.
• Remember that meconium passage alone doesn't equal MAS - aspiration must occur for syndrome to develop.