Patent mean "open". The ductus arteriosus is a blood vessel connecting the main vessel leading to the lungs (pulmonary artery) to the main vessel of the body (aorta).
Before birth, the mother and placenta take care of the oxygen needs of the fetus (baby before birth). The fetus does not need to use his/her lungs. Therefore, very little blood needs to go to the lungs to help them grow. The ductus arteriosus allows most of the blood to bypass the lungs and go the rest of the body. After birth, the baby must use his/her lungs to take in oxygen and get rid of carbon dioxide. Now, the blood from the pulmonary artery needs to go to the lungs to pick up oxygen instead of going through the ductus arteriosus. Normally after birth the ductus gradually narrows and then closes in the first few hours to days. In premature infants, especially those who have had respiratory distress syndrome, this blood vessel may stay open.
Blood goes in the opposite direction through this vessel than it would in the fetus. It goes from the aorta to the lungs. In addition, there is normal blood flow from the heart to the lungs. This is too much blood into the baby's lung. Fluid in the lung increases and it makes it harder for the baby to breathe. The PDA increases the work of the heart and the baby can develop heart failure if the amount of blood flowing through the PDA is large. How will doctors know if my baby has a PDA?
Your doctors may suspect your baby has a PDA if :
s/he needs more oxygen or help breathing when s/he should be needing less
his/ her breathing is more difficult or there is much more apnea
the doctor or nurse hears a murmur (an abnormal noise over the heart)
the baby's heart rate increases and/or the pulse changes
If a PDA is suspected, your baby will probably have an ECHOCARDIOGRAM. In this test sound waves are used to give a picture of the baby's heart and determine the amount of blood flow through the PDA. It is painless and is similar in principle to the ultrasound that many women have when they are pregnant.
If the ductus is very small and there is only a tiny amount of blood flowing through it, your baby's doctors may wait to see if it closes on its own.
The most common drug used to treat a PDA is indomethacin. It causes the ductus to narrow. As the ductus narrows, less blood flow can go through it. Indomethacin may also cause your baby to make less urine. Sometimes more than one course of indomethacin is needed to close a ductus. Some physicians use ibuprofen instead of indomethacin.
Your doctor might also decide to decrease the amount of fluid that your baby is receiving while the PDA is open.
Occasionally another drug called a diuretic is given to decrease the fluid in the lungs and increase the amount of urine that your baby makes.
If the ductus will not close with medication, or if your baby's doctors do not think your baby should have these drugs, the PDA may be tied off (ligated) surgically through an incision in the baby's chest.
It is very rare for a baby to also have a heart malformation. A PDA in a premature baby is not considered a malformation. The echocardiogram will determine if your baby's heart is otherwise normal.
Sometimes drugs only close the ductus for hours or a few days. A second course may be needed, or surgery may be required. However, once the baby is over his/her problems of prematurity and the PDA has gone away, it will not come back later in life.