Clinical findings in an infant with pulmonary hypertension include which of the following?

• A. Increased pulmonary blood flow
• B. Increased pulmonary vascular contractility
• C. Left to right shunting
• D. Decreased systemic blood pressure

Answer: (B)

Pulmonary hypertension in newborns is driven by elevated pulmonary vascular resistance from ongoing pulmonary vasoconstriction, so the pulmonary arteries stay in a high–tone state. That increased pulmonary vascular contractility raises resistance to blood flow through the lungs, leading to right-to-left shunting through fetal channels like the foramen ovale and ductus arteriosus and resulting in systemic hypoxemia. This pattern—high PVR due to vasoconstriction and the resultant right-to-left flow—best matches the concept of increased pulmonary vascular contractility. Increased pulmonary blood flow or left-to-right shunting would not fit the vignette of pulmonary hypertension, and decreased systemic blood pressure is not a defining feature here.