PDA Patent Ductus Arteriosus questions with correct answers

What is the Physiologic purpose of the PDA? - Answer Purpose in the fetus is to divert blood away from lungs in utero -Lungs are not needed in utero to oxygenate the blood, oxygenation is provided by the placenta How does the PDA work? - Answer -After birth and clamping of the umbilical cord and the first breath, the pulmonary vasculature relaxes, allowing blood to flow in, and systemic blood pressure rises, preventing continued flow of blood from the aorta crossing the PDA into pulmonary artery vessels -Within hours to a few days the PDA should close Risk factors for Premature infants with PDA - Answer -Lack of maternal antenatal steroids -Premature infant less then 1500g birth weight, but usually less than 1000g -Need for ventilation/surfactant due to RDS -Liberal use of IV fluids -Low platelets -Sepsis -Hypoxia (oxygen is vasoconstrictor)