pediatrics
Meconium Aspiration Syndrome
Pathophysiology of Meconium Aspiration Syndrome
The mechanisms by which aspiration induces the clinical syndrome probably include Nonspecific cytokine release Airway obstruction Decreased surfactant production and surfactant inactivation Chemical pneumonitis Underlying physiologic stressors also may contribute. If complete bronchial obstruction occurs, atelectasis results; partial blockage leads to air trapping on expiration, resulting in hyperexpansion of the lungs and possibly Pulmonary Air-Leak Syndromes with pneumomediastinum or pneumothorax. The risk of air leak is further increased because of the decreased lung compliance caused by decreased surfactant production and inactivated surfactant. PPH can be associated with meconium aspiration as a comorbid condition or because of continuing hypoxia. Neonates also may aspirate vernix caseosa, amniotic fluid, or blood of maternal or fetal origin during delivery, all of which can cause respiratory distress and signs of aspiration pneumonia on chest x-ray. 