Neonatal Nurse Practitioner Practice Exam

What signifies a neonatal's low lung volumes on an x-ray?

1. Meconium aspiration

2. Immature lungs

3. Congenital defects

The correct answer is: Immature lungs

A neonatal's low lung volumes on an x-ray are indicative of immature lungs. In neonates, particularly preterm infants, lung development may not be fully realized, leading to conditions such as respiratory distress syndrome (RDS). RDS is commonly due to a deficiency of surfactant, a surfacing agent that stabilizes the alveoli and reduces surface tension, allowing the lungs to expand properly. When the lungs are immature, they are often not filled adequately with air, resulting in the appearance of low lung volumes on radiologic examinations. This can manifest as increased opacity (whiteness) in the lung fields due to fluid or collapse of alveoli (atelectasis), which further signifies inadequate gas exchange capacity. In contrast, conditions like meconium aspiration may lead to other radiographic findings such as hyperinflation or patchy infiltrates, but not specifically low lung volumes. Congenital defects can also result in various lung imaging abnormalities depending on the nature of the defect but do not typically correlate directly with the overall maturity and volume capacity of the lungs. Therefore, the identification of low lung volume is most directly associated with lung immaturity.