While on ECMO, the body can have time to absorb the meconium and for all the associated disorders to resolve. There has been an excellent response to this treatment, as the survival rate of MAS while on ECMO is more than 94%.Ventilation of infants with MAS can be challenging and, as MAS can affect each individual differently, ventilation administration may need to be customised. Some newborns with MAS can have homogenous lung changes and others can have inconsistent and patchy changes to their lungs. It is common for sedation and muscle relaxants to be used to optimise ventilation and minimise the risk of pneumothorax associated with dyssynchronous breathing. Inhaled nitric oxide
Inhaled nitric oxide (iNO) acts on vascular smooth muscle causing selective pulmonary vasodilation. This is ideal in the treatment of PPHN as it causes vasodilation within ventilated areas of the lung thus, decreasing the ventilation-perfusion mismatch and thereby, improves oxygenation. Treatment utilising iNO decreases the need for ECMO and mortality in newborns with hypoxic respiratory failure and PPHN as a result of MAS. However, approximately 30-50% of infants with PPHN do not respond to iNO therapy. Antiinflammatories
As inflammation is such a huge issue in MAS, treatment has consisted of anti-inflammatories. Glucocorticoids
Glucocorticoids have a strong anti-inflammatory activity and works to reduce the migration and activation of neutrophils, eosinophils, mononuclear cells, and other cells. They reduce the migration of neutrophils into the lungs ergo, decreasing their adherence to the endothelium.
Meconium aspiration syndrome (MAS) also known as neonatal aspiration of meconium is a medical condition affecting newborn infants. It describes the spectrum of disorders and pathophysiology of newborns born in meconium-stained amniotic fluid (MSAF) and have meconium within their lungs. Therefore, MAS has a wide range of severity depending on what conditions and complications develop after parturition. Furthermore, the pathophysiology of MAS is multifactorial and extremely complex which is why it is the leading cause of morbidity and mortality in term infants.The word meconium is derived from the Greek word mēkōnion meaning juice from the opium poppy as the sedative effects it had on the foetus were observed by Aristotle.Meconium is a sticky dark-green substance which contains gastrointestinal secretions, amniotic fluid, bile acids, bile, blood, mucus, cholesterol, pancreatic secretions, lanugo, vernix caseosa and cellular debris. Meconium accumulates in the foetal gastrointestinal tract throughout the third trimester of pregnancy and it is the first intestinal discharge released within the first 48 hours after birth. Notably, since meconium and the whole content of the gastrointestinal tract is located extracorporeally, its constituents are hidden and normally not recognised by the foetal immune system.For the meconium within the amniotic fluid to successfully cause MAS, it has to enter the respiratory system during the period when the fluid-filled lungs transition into an air-filled organ capable of gas exchange. Causes
The main theories of meconium passage into amniotic fluid are caused by fetal maturity or from foetal stress as a result of hypoxia or infection.