What is the management of meconium aspiration syndrome?

Management of Meconium Aspiration Syndrome

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

Initial Assessment and Management

• For infants born through meconium-stained amniotic fluid, a team skilled in tracheal intubation should be present at delivery due to increased risk of requiring resuscitation 1
• If the infant is vigorous (good respiratory effort and muscle tone), allow the infant to remain with the mother and receive routine newborn care 1
• Gentle clearing of meconium from the mouth and nose with a bulb syringe may be done if necessary 1
• For nonvigorous infants (poor muscle tone and inadequate respiratory effort), proceed with appropriate resuscitation measures without routine immediate direct laryngoscopy and tracheal suctioning 1
• Intubation and suctioning should be considered only if there is evidence of airway obstruction 1

Respiratory Support

• Supplemental oxygen is the mainstay of therapy for MAS, with approximately one-third of infants requiring intubation and mechanical ventilation 2
• 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
• For term infants, initiate resuscitation with room air (21% oxygen at sea level) 1
• For ventilated infants with MAS, consider:
  • Higher ventilator pressures with relatively long inspiratory time and slow ventilator rate to achieve adequate oxygenation 2
  • Positive end-expiratory pressure (PEEP) to assist in establishing functional residual capacity 1
  • High-frequency ventilation for infants with refractory hypoxemia and/or gas trapping 2

Advanced Therapies for Severe MAS

• Inhaled nitric oxide (iNO) is effective for MAS-associated pulmonary hypertension 3, 2

  • The FDA-approved dose is 20 ppm, with significant improvements in oxygenation and reduction in the need for ECMO 3
  • In the NINOS study, iNO reduced the combined incidence of death and/or need for ECMO (46% vs 64%, p=0.006) in infants with hypoxic respiratory failure, with MAS being the most common etiology (49%) 3
  • Monitor methemoglobin levels during iNO therapy, as levels can increase during treatment 3

• Consider surfactant administration in selected cases 2, 4

  • Surfactant can help counteract the surfactant inhibition caused by meconium 5, 2

• Lung lavage may be beneficial in selected cases with significant airway obstruction 2, 4

• Extracorporeal membrane oxygenation (ECMO) should be considered for the most severe cases unresponsive to other therapies 5, 2

Supportive Care

• Maintain normothermia, as hypothermia increases mortality risk 1
• Consider antibiotic therapy, as meconium in airways can predispose to infection 6
• Provide adequate fluid balance and caloric intake 5
• Monitor vital signs and provide chest physiotherapy as needed 5

Prevention

• Prevention is crucial in managing MAS 5, 7
• Prenatal care should include:
  • Constant fetal heart rate monitoring during labor 5
  • Examination of acid-base equilibrium in capillary blood from the fetal scalp when indicated 5
  • Consider amnioinfusion in selected cases, though further studies are needed to confirm benefits 5

Prognosis and Follow-up

• With judicious use of available ventilation modes and adjunctive therapies, even infants with severe MAS can usually be supported through the disease 2
• Long-term follow-up is important as infants with MAS may have increased risk of respiratory and neurodevelopmental issues 3