Most infants born through MSAF do not require any treatments (other than routine postnatal care) as they show no signs of respiratory distress, as only approximately 5% of infants born through MSAF develop<unk> . However, infants which do develop<unk>  need to be admitted to a neonatal unit where they will be closely observed and provided any treatments needed. Observations include monitoring heart rate, respiratory rate, oxygen saturation and blood glucose (to detect worsening respiratory acidosis or the development of hypoglycemia). In general, treatment of<unk>  is more supportive in nature. Assisted ventilation techniques To clear the airways of<unk> , tracheal suctioning can be used however, the efficacy of this method is in question and it can cause harm. In cases of<unk> , there is a need for supplemental oxygen for at least 12 hours in order to maintain oxygen saturation of haemoglobin at 92% or more. The severity of respiratory distress can vary significantly between newborns with<unk> , as some require minimal or no supplemental oxygen requirement and, in severe cases, mechanical ventilation may be needed. The desired oxygen saturation is between 90-95% and PaO2 may be as high as 90mmHg. In cases where there is thick<unk>  deep within the lungs, mechanical ventilation may be required. In extreme cases, extracorporeal membrane oxygenation (ECMO) may be utilised in infants who fail to respond to ventilation therapy. While on ECMO, the body can have time to absorb the<unk>  and for all the associated disorders to resolve. There has been an excellent response to this treatment, as the survival rate of<unk>  while on ECMO is more than 94%. Ventilation of infants with<unk>  can be challenging and, as<unk>  can affect each individual differently, ventilation administration may need to be customised. Some newborns with<unk>  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<unk> . However, approximately 30-50% of infants with PPHN do not respond to iNO therapy. Antiinflammatories As inflammation is such a huge issue in<unk> , 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. Thus, there is a reduction in the action of mediators released from these cells and therefore, a reduced inflammatory response. Glucocorticoids also possess a genomic mechanism of action in which, once bound to a glucocorticoid receptor, the activated complex moves into the nucleus and inhibits transcription of mRNA. Ultimately, effecting whether various proteins get produced or not. Inhibiting the transcription of nuclear factor (NF-κB) and protein activator (AP-1) attenuates the expression of pro-inflammatory cytokines (IL-1, IL-6, IL-8 and TNF etc.), enzymes (PLA2, COX-2, iNOs etc.) and other biologically active substances. The anti-inflammatory effect of glucocorticoids is also demonstrated by enhancing the activity of lipocortines which inhibit the activity of PLA2 and therefore, decrease the production of arachidonic acid and mediators of lipoxygenase and cyclooxygenase pathways. Anti-inflammatories need to be administered as quickly as possible as the effect of these drugs can diminish even just an hour after<unk><unk> . For example, early administration of dexamethasone significantly enhanced gas exchange, reduced ventilatory pressures, decreased the number of neutrophils in the bronchoalveolar area, reduced oedema formation and oxidative lung injury. However, glucocorticoids may increase the risk of infection and this risk increases with the dose and duration of glucocorticoid treatment. Other issues can arise, such as aggravation of diabetes mellitus, osteoporosis, skin atrophy and growth retardation in children. Inhibitors of phosphodiesterase Phosphodiesterases (PDE) degrades cAMP and cGMP and, within the respiratory system of a newborn with<unk> , various isoforms of PDE may be involved due to their pro-inflammatory and smooth muscle contractile activity. Therefore, non-selective and selective inhibitors of PDE could potentially be used in<unk>  therapy. However, the use of PDE inhibitors can cause cardiovascular side effects. Non-selective PDE inhibitors, such as methylxanthines, increase concentrations of cAMP and cGMP in the cells leading to bronchodilation and vasodilation. Additionally, methylxanthines decreases the concentrations of calcium, acetylcholine and monoamines, this controls the release of various mediators of inflammation and bronchoconstriction, including prostaglandins. Selective PDE inhibitors target one subtype of phosphodiesterase and in<unk>  the activities of PDE-3, PDE-4, PDE-5 and PDE-7 may become enhanced. For example, Milrinone (a selective PDE3 inhibitor) improved oxygenation and survival of neonates with<unk> . Inhibitors of cyclooxygenase Arachidonic acid is metabolised, via cyclooxygenase (COX) and lipoxygenase, to various substances including prostaglandins and leukotrienes, which exhibit potent pro-inflammatory and vasoactive effects. By inhibiting COX, and more specifically COX-2, (either through selective or non-selective drugs) inflammation and oedema can be reduced. However, COX inhibitors may induce peptic ulcers and cause hyperkalemia and hypernatremia. Additionally, COX inhibitors have not shown any great response in the treatment of<unk> . Antibiotics<unk>  is typically sterile however, it can contain various cultures of bacteria so appropriate antibiotics may need to be prescribed. Surfactant treatment Lung lavage with diluted surfactant is a new treatment with potentially beneficial results depending on how early it is administered in newborns with<unk> . This treatment shows promise as it has a significant effect on air leaks, pneumothorax, the need for ECMO and death. Early intervention and using it on newborns with mild<unk>  is more effective. However, there are risks as a large volume of fluid instillation to the lung of a newborn can be dangerous (particularly in cases of severe<unk>  with pulmonary hypertension) as it can exacerbate hypoxia and lead to mortality. Previous treatments Originally, it was believed that<unk>  developed as a result of the<unk>  being a physical blockage of the airways. Thus, to prevent newborns, who were born through MSAF, from developing<unk> , suctioning of the oropharyngeal and nasopharyngeal area before delivery of the shoulders followed by tracheal<unk>  was utilised for 20 years. This treatment was believed to be effective as it was reported to significantly decrease the incidence of<unk>  compared to those newborns born through MSAF who were not treated. This claim was later disproved and future studies concluded that oropharyngeal and nasopharyngeal suctioning, before delivery of the shoulders in infants born through MSAF, does not prevent<unk>  or its complications. In fact, it can cause more issues and damage (e.g. mucosal damage), thus it is not a recommended preventative treatment. Suctioning may not significantly reduce the incidence of<unk>  as<unk>  passage and<unk>  may occur in-utero. Thereby making the suctioning redundant and useless as the<unk>  may already be deep within the lungs at the time of birth. Historically, amnioinfusion has been used when MSAF was present, which involves a transcervical infusion of fluid during labour. The idea was to dilute the thick<unk>  to reduce its potential pathophysiology and reduce cases of<unk> , since<unk>  is more prevalent in cases of thick<unk> . However, there are associated risks, such as umbilical cord prolapse and prolongation of labour. The UK National Institute of Health and Clinical Excellence (NICE) Guidelines recommend against the use of amnioinfusion in women with MSAF.
Meconium aspiration syndrome
Infantile apnea
Tracheoesophageal fistula
Tracheomalacia
Laryngotracheal stenosis
Upper airway resistance syndrome
Transient tachypnea of the newborn
Laryngomalacia