What are the management strategies for meconium aspiration syndrome?

Management of Meconium Aspiration Syndrome

For infants with meconium aspiration syndrome (MAS), immediate resuscitation without routine direct laryngoscopy and tracheal suctioning is recommended, with subsequent respiratory support tailored to the severity of respiratory distress. 1, 2

Initial Assessment and Management

• For deliveries with meconium-stained amniotic fluid, a team skilled in tracheal intubation should be present due to increased risk of requiring resuscitation 1, 2

• For vigorous infants (good respiratory effort, muscle tone, and heart rate >100/min):

  • Allow the infant to remain with the mother and receive routine newborn care 1, 2
  • Gentle clearing of meconium from the mouth and nose with a bulb syringe may be done if necessary 1, 2

• For nonvigorous infants (heart rate <100/min, decreased muscle tone, and/or depressed breathing):

  • Proceed with immediate resuscitation without routine direct laryngoscopy and tracheal suctioning 1, 2
  • Consider intubation and suctioning only if there is evidence of airway obstruction 1, 2

Respiratory Support

• Use pulse oximetry to guide oxygen therapy when resuscitation is anticipated, when positive pressure ventilation is administered, when central cyanosis persists beyond 5-10 minutes, or when supplementary oxygen is administered 1, 2

• Initiate resuscitation with room air (21% oxygen) for term infants 1, 2

• For infants requiring mechanical ventilation:

  • Higher ventilator pressures, longer inspiratory times, and slower ventilator rates may be necessary to achieve adequate oxygenation 3
  • Consider positive end-expiratory pressure (PEEP) to establish functional residual capacity 2
  • High-frequency ventilation (oscillatory or jet) should be considered for infants with refractory hypoxemia and/or gas trapping 3

Advanced Therapies for Severe MAS

• Inhaled nitric oxide is effective for infants with persistent pulmonary hypertension associated with MAS 4, 3

  • The NINOS study demonstrated that inhaled nitric oxide reduced the need for ECMO in infants with hypoxic respiratory failure, including those with MAS 4
  • Methemoglobin levels should be monitored during nitric oxide therapy, with levels typically remaining below 1% at 5-20 ppm dosing 4

• Consider surfactant administration in selected cases with evidence of surfactant dysfunction 3, 5

  • Meconium causes surfactant inactivation, and exogenous surfactant may improve oxygenation 3, 5

• Lung lavage may be beneficial in selected severe cases to remove meconium from the airways 3, 5

• Extracorporeal membrane oxygenation (ECMO) should be considered for the most severe cases unresponsive to other therapies 4, 6

Supportive Care

• Maintain normothermia, as hypothermia increases mortality risk 1, 2

• Provide appropriate fluid balance and caloric intake 6

• Consider antibiotic therapy, as meconium-stained fluid increases risk of infection 6, 5

• Chest physiotherapy and airway suctioning may help clear secretions 6

Common Pitfalls and Caveats

• Routine tracheal intubation and suctioning for nonvigorous infants born through meconium-stained amniotic fluid is no longer recommended as it delays ventilation without improving outcomes 1, 2

• Avoid excessive oxygen administration, as hyperoxia can worsen pulmonary hypertension and cause oxidative injury 3

• Monitor for complications including air leaks (pneumothorax, pneumomediastinum), persistent pulmonary hypertension, and secondary infections 3, 5

• Recognize that MAS often presents with significant ventilation-perfusion mismatch requiring careful respiratory management 5