An infant is experiencing dyspnea related to patent ductus arteriosus (PDA). What does the nurse understand regarding why dyspnea occurs?

A. Blood is shunted past the pulmonary circulation, causing pulmonary hypoxia: In PDA, blood goes to the lungs excessively, not past it, so this is incorrect. B. Blood is circulated through the ductus from the pulmonary artery to the aorta, bypassing the left side of the heart: This is fetal circulation physiology; in PDA postnatally, the shunt is usually from the aorta to the pulmonary artery. C. Blood is shunted past cardiac arteries, causing myocardial hypoxia: PDA doesn’t bypass the cardiac arteries, so this is incorrect. D. Blood is circulated through the lungs again, causing pulmonary circulatory congestion: In PDA, oxygenated blood from the aorta is shunted to the pulmonary artery, increasing blood flow to the lungs, leading to pulmonary congestion and dyspnea.