Meconium aspiration syndrome
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 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
- It should be performed immediately by an experienced clinician
Current guidelines recommend that ETT suctioning be performed once only. This is the only circumstance during neonatal resuscitation where drying and rubbing the infant is NOT the first action. Where there is meconium-stained liquor and a flat baby, suction under direct vision FIRST.
Following ETT suctioning, start standard resuscitation 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.
After suctioning, the infant begins to cry. Continuous pressure ventilation is continued until the respiratory effort is regular. Following an unremarkable examination, the baby is returned to his parents.
You are called back to the 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 of 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?
- Maintain adequate oxygenation and ventilation: If saturations are low, start with supplementary oxygen. If they remain low and there is ongoing respiratory distress, CPAP may be required. Discuss this with the neonatal retrieval service early.
- CXR: If available out-of-hours in your hospital, CXR should be performed on all neonates with ongoing respiratory distress. Remember to always insert a nasogastric tube before the CXR.
- Feeding support: start with intravenous fluids at 60ml/kg/day if the infant is tachypnoeic and in 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 before 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 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.
