What is the most common cause of hypoxemia in neonatal respiratory distress syndrome (NRDS)?

In neonatal respiratory distress syndrome (NRDS), the most common cause of hypoxemia is atelectasis. This condition is characterized by the collapse of the alveoli in the lungs, which significantly reduces the surface area available for gas exchange. In NRDS, there is a deficiency of surfactant, a substance that helps keep the alveoli open by reducing surface tension. When surfactant levels are low, the alveoli can collapse after each breath, leading to atelectasis.

As a result of atelectasis, the infant is unable to adequately ventilate the affected areas of the lungs, leading to impaired oxygenation and subsequent hypoxemia. The critical role of surfactant in maintaining alveolar stability is crucial in understanding NRDS, as surfactant deficiency is a primary pathological mechanism leading to atelectasis in premature infants.

In contrast, while pneumothorax, meconium aspiration, and infection can also cause respiratory issues in neonates, they are not the most prevalent causes of hypoxemia specifically in the context of NRDS. Pneumothorax involves air in the pleural space but is less common in the absence of underlying lung disease. Meconium aspiration syndrome leads to airway obstruction and inflammation but