Meconium aspiration syndrome

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It is 3am, you are the paediatric registrar on in a regional hospital. You are called to attend a term vaginal delivery, with meconium stained liquor. As you arrive a flat baby is transferred to the resuscitaire. 

Bottom Line

  • Meconium liquor deliveries are common, approximately 10-20% of births. Only a very small proportion of these infants will aspirate meconium and as a result develop respiratory distress and hypoxemia.
  • Endotracheal intubation and suctioning should be performed only if the baby has significant respiratory distress. Otherwise leave the baby alone.
  • Only in the setting of meconium stained liquor and a flat baby, should intubation and suction of any meconium from below the cord, be the first action during resuscitation.
  • Baby should not have suction on the perineum; it does no good and wastes time.
  • Call for help early!

What are the indications for ETT suctioning?

Indications for intubation and suctioning include:

  • Decreased muscle tone
  • Poor or absent respiratory effort
  • Should be performed immediately by an experienced clinician

Current guidelines recommend that ETT suctioning should be performed once only. This is the only circumstance during neonatal resuscitation, where drying and rubbing infant is NOT the first action. Where there is meconium-stained liquor and a flat baby, suction under direct vision FIRST. Following ETT suctioning, normal resuscitation should be undertaken immediately. The Australian newborn life support guideline is an excellent flow chart to follow. It is important to identify if your hospital uses different guidelines. 

Post suctioning the infant begins to cry, continuous pressure ventilation is continued until respiratory effort is regular. Following an unremarkable examination. The baby is returned to his parents. 

You are called back to birth suite when the infant is 20 minutes of age. He has moderate work of breathing and is tachypnoeic. Pulse oximetry is not available. 

What are the possible causes for the underlying condition?

  • Meconium aspiration
  • Transient tachypnea of the newborn
  • Hyaline membrane disease
  • Delayed transition from fetal circulation
  • Sepsis
  • Pneumonia
  • Pneumothorax

What is meconium aspiration syndrome?

  • Meconium aspiration syndrome (MAS) is defined by the early onset of hypoxaemia and respiratory distress in the context of meconium stained liquor.
  • MAS occurs in 1.5 per 1000 live births
  • Meconium interferes with respiration in several ways. It causes airway obstruction, irritation, inflammation, reduced surfactant efficacy and infection.  These children can be very hypoxic and difficult to ventilate.
  • The majority of infants with MAS will need limited intervention- oxygen and support with feeding, whilst others will require respiratory support.
  • MAS infants can deteriorate quickly. Pneumothorax is a significant complication. It is important to seek help early and notify senior staff.

Following a quick discussion with his parents, you transfer the neonate to the special care nursery. Chest auscultation reveals widespread inspiratory crackles.

What is your initial management?

  • Maintenance of adequate oxygenation and ventilation: Start with supplementary oxygen, if saturations low. CPAP may be required if oxygen saturations remain low and there is ongoing respiratory distress. Discuss with neonatal retrieval service early.
  • CXR: if available in your hospital out of hours, CXR should be performed in all neonates with ongoing respiratory distress. Remember always insert a naso-gastric tube prior to the CXR.
  • Feeding support: start with intravenous fluids at 60ml/kg/day if the infant continues to be tachypnoeic and have distress. Keep NBM until respiratory distress improves.
  • Empirical antibiotic therapy: as per your local guidelines for suspected neonatal sepsis. Blood cultures need to be obtained prior to the initiation of IV antibiotics. A full blood count and blood gas are usually also useful.

Most neonates with meconium aspiration syndrome usually do well. Less than 10% will require a neonatal intensive care. A very small proportion will develop chronic lung disease. 

 

References

Davies, M, Cartwright, D & Inglis, G 2009, Pocket notes on neonatology, 2nd edition, Elsevier.

Victorian newborn emergency transport service 2012, Neonatal handbook.

Queensland health 2011, Neonatal resuscitation.

 

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About 

Dr Jasmine Antoine BSC, MBBS, MPH, an Australian-based paediatric trainee who is interested in neonatology and general paediatrics. She's passionate about medical education and how social attributes impact health. jasmine@dontforgetthebubbles.com | @jasmine_antoine | Jasmine's DFTB posts