开放性动脉导管:A shortvesselthrough whichbloodheaded from the heart via the肺动脉to thelungsis shunted before birth. This blood is shunted away from the lungs and returned to theaorta. When the分流器is open, it is said to bepatent. Apatent ductus arteriosus(PDA) usually closes at or shortly after birth, and blood is permitted from that moment on to course freely to the lungs. If theductusstays open, flow reverses, and blood from the aorta is shunted into thepulmonaryarteryand recirculated through the lungs. The PDA may close later on its own, or it may need to be ligated (tied off) surgically.
