Neonatal Nurse Practitioner Practice Exam

A chest x-ray shows low lung volumes in a neonate. This is most consistent with?

1. Immature lungs

2. Meconium aspiration

3. Neonatal pneumonitis

The correct answer is: Immature lungs

Low lung volumes observed on a chest x-ray in a neonate are most consistent with immature lungs. In neonates, especially those born prematurely, lung development may not be fully completed, resulting in inadequate expansion of alveoli. This leads to a decrease in lung volume, which is commonly seen in conditions such as respiratory distress syndrome (RDS) associated with surfactant deficiency. In contrast, meconium aspiration syndrome is characterized by the presence of meconium in the airways, often leading to areas of over-inflation or atelectasis rather than uniformly low lung volumes. Likewise, neonatal pneumonitis typically presents with other signs such as opacities or infiltrates on a chest x-ray and is not primarily characterized by low lung volumes. Thus, the presentation of low lung volumes directly supports the diagnosis of immature lungs, reinforcing the significance of adequate surfactant production and lung maturity in the neonatal population.