TY - CHAP M1 - Book, Section TI - Patent Ductus Arteriosus: From Bench to Bedside A1 - Backes, Carl H. A1 - Kovalchin, Claire A1 - Rivera, Brian K. A1 - Smith, Charles V. A2 - Kline, Mark W. Y1 - 2018 N1 - T2 - Rudolph's Pediatrics, 23e AB - The ductus arteriosus (DA) is a vital component of the fetal circulation, when the placenta is the source of oxygen to the fetus. The DA provides a conduit for blood to bypass the high resistance pulmonary vascular bed and shunt toward the descending aorta and low-resistance placental circulation. At birth, the lungs are inflated and resistance in the pulmonary vascular bed decreases as the lungs become the source of oxygenation, rendering the DA no longer necessary. Over the first few days of life, the DA undergoes active constriction and occlusion; failure of this process results in a patent ductus arteriosus (PDA). In the majority (> 95%) of term infants and those born > 28 weeks of gestation, closure of the ductus occurs within hours. In contrast, PDAs occur in 70% of infants born prior to 28 weeks of gestation, with an incidence that is inversely proportional to gestational age (GA) at birth. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/29 UR - accesspediatrics.mhmedical.com/content.aspx?aid=1182921105 ER -