During the transition of the pulmonary system, what is one key change?

• A. Decreased lung fluid clearance
• B. Decreased surfactant secretion
• C. Increased lung fluid clearance
• D. Increased surfactant secretion

Answer: (D)

One key change during the transition of the pulmonary system in newborns is the increased secretion of surfactant. Surfactant is a substance that reduces surface tension within the alveoli in the lungs, which is crucial for preventing the collapse of these tiny air sacs. This increase in surfactant is vital as the newborn takes its first breaths after birth, allowing the lungs to expand more easily and facilitating effective gas exchange.

The production of surfactant begins during fetal development, but it ramps up significantly just before and after delivery as the newborn adapts to breathing air instead of relying on placental oxygen. This increase in surfactant plays a critical role in establishing functional breathing patterns and aids in preventing respiratory distress, which can occur in infants who are born prematurely or have insufficient surfactant.

In contrast, during this transition, there is a significant reduction in lung fluid clearance as the lungs fill with air instead of fluid, as well as a decrease in lung fluid overall, which are not conducive to the proper respiratory function needed for effective breathing in the neonatal period.