What is the management of meconium aspiration syndrome (MAS) in the Neonatal Intensive Care Unit (NICU)?

Management of Meconium Aspiration Syndrome (MAS) in the NICU

For infants with meconium aspiration syndrome (MAS), immediate resuscitation without routine tracheal intubation and suctioning is recommended, followed by supportive respiratory care including oxygen therapy, ventilation strategies, and consideration of adjunctive therapies such as surfactant and inhaled nitric oxide for severe cases. 1

Initial Management

• Resuscitation Approach: For nonvigorous infants born through meconium-stained amniotic fluid (MSAF), immediate resuscitation without routine direct laryngoscopy and tracheal suctioning is recommended 1
• Tracheal intubation and suctioning should be considered only if there is evidence of airway obstruction by meconium 2
• A team skilled in neonatal intubation should be present at delivery of infants with MSAF due to increased risk of requiring resuscitation 2
• If the infant is vigorous at birth, allow routine newborn care without intervention 2

Respiratory Support

Oxygen Therapy

• Use pulse oximetry to guide oxygen therapy when resuscitation is anticipated or when positive pressure ventilation is administered 2
• Initiate resuscitation with room air (21% oxygen) for term infants 2
• Titrate oxygen based on pulse oximetry readings to maintain appropriate saturation targets 1

Ventilation Strategies

• For ventilated infants with MAS, consider the following approaches:
  • Use positive end-expiratory pressure (PEEP) to establish and maintain functional residual capacity 2, 3
  • Higher ventilator pressures may be necessary due to poor lung compliance 3
  • Consider longer inspiratory times and slower ventilator rates to allow for adequate gas exchange and prevent air trapping 3
  • For infants with refractory hypoxemia or significant gas trapping, high-frequency ventilation may be beneficial 3

Advanced Therapies for Severe MAS

Surfactant Therapy

• Consider surfactant administration in selected cases with significant respiratory distress and oxygen requirements 3, 4
• Surfactant can help counteract the inhibition of endogenous surfactant caused by meconium 5

Inhaled Nitric Oxide (iNO)

• For infants with MAS complicated by persistent pulmonary hypertension of the newborn (PPHN):
  • Inhaled nitric oxide at 20 ppm is effective in reducing the need for extracorporeal membrane oxygenation (ECMO) 6
  • In the NINOS study, significantly fewer infants with hypoxic respiratory failure (49% due to MAS) in the nitric oxide group required ECMO compared with controls (39% vs. 55%, p = 0.014) 6
  • The combined incidence of death and/or initiation of ECMO showed a significant advantage for the nitric oxide treated group (46% vs. 64%, p = 0.006) 6

ECMO Consideration

• For severe cases unresponsive to maximal conventional therapy and inhaled nitric oxide, ECMO should be considered if available 3, 5

Supportive Care

• Maintain normothermia, as hypothermia increases mortality risk 1, 2
• Provide appropriate fluid management and cardiovascular support as needed 5
• Monitor for and treat complications such as pneumothorax, pulmonary hemorrhage, and persistent pulmonary hypertension 4

Monitoring and Follow-up

• Continuous monitoring of vital signs, oxygen saturation, and blood gases is essential 3
• Serial chest radiographs to assess disease progression and complications 4
• Monitor for potential long-term respiratory and neurodevelopmental sequelae, especially in severe cases 5

Common Pitfalls to Avoid

• Delaying initiation of ventilation in nonvigorous infants while attempting intubation and suctioning 1
• Routine tracheal suctioning in all infants with MSAF is no longer recommended and may cause harm by delaying effective ventilation 1
• Overventilation can lead to air leaks due to the already compromised lung compliance in MAS 3
• Failure to recognize and treat associated pulmonary hypertension can lead to worsening hypoxemia 6, 5