Which factor is the major contributor to the risk of pulmonary hemorrhage in preterm infants?

• A. Patent ductus arteriosus
• B. Pneumothorax
• C. Pulmonary interstitial emphysema
• D. Pulmonary edema

Answer: (A)

A persistent patent ductus arteriosus drives the risk of pulmonary hemorrhage through hemodynamic overload of the immature lung. When the ductus remains open, blood shunts from the systemic circulation into the pulmonary artery, increasing pulmonary blood flow and raising capillary hydrostatic pressure. That extra pressure makes the fragile capillaries in the preterm lung prone to leakage and rupture, so blood can flood into the alveolar spaces, producing a pulmonary hemorrhage. The immature lungs are not equipped to handle this abrupt rise in flow and pressure, and edema from the high pulmonary pressures further destabilizes the vasculature. While pneumothorax, pulmonary interstitial emphysema, and pulmonary edema can accompany severe respiratory compromise, the PDA’s sustained hemodynamic effect is the primary driver that sets the stage for hemorrhage risk in this population.