An Explanation of PDA

PDA - Patent Ductus Arteriosus

While in the womb, a baby receives oxygen from his mother through the placenta. Since there is no need for the blood to travel to the lungs to pick up oxygen, the blood bypasses the lungs, following the path of a blood vessel called the ductus arteriosus (sometimes just called the ductus). In the first day after a baby's birth, the ductus closes on its own, allowing blood to flow into the lungs to pick up oxygen, then back to the heart and out to the rest of the body.

In premature infants, the ductus tends to stay open and some of the blood continues to bypass the lungs, circulating out to the body without picking up vital oxygen. This is called a patent (open) ductus arteriosus, or PDA. This is a common problem in very young preemies, occurring in about 45% of infants under 3 lbs, 14 oz, and almost 80% of infants under 2lbs, 3 oz. Truman's birth weight was only one pound, four ounces.

For the first few days, a preemie with a PDA will probably need a little more oxygen than usual (which he would probably need even without the PDA, because his lungs are immature), but the PDA doesn't affect the function of the heart and lungs significantly. However, over the next few days or weeks, this extra blood flow can put a strain on the heart and lungs. If it is allowed to continue, the heart can tire out, resulting in congestive heart failure. A PDA can also lead to pulmonary edema, in which fluid from the blood leaks into the tissues of the lungs, making it more difficult for the baby to breathe.

The severity of the problems caused by a PDA depends on how much blood is flowing through it. Small PDAs cause only minor problems and may close eventually on their own. A large PDA will probably remain open and need treatment before it causes significant problems.


How PDA is Treated

If the doctors suspect a baby has a PDA, their suspicions can be confirmed with an ultrasound of the heart, called an echocardiogram (or echo for short). This test is painless, and is usually done while the infant is resting.

Small PDAs are easily treated with an aspirin-like medication called indomethacin. This will help the ductus to close after one or more doses. The doctors might also reduce the baby's fluid intake and give him a diuretic to get rid of extra fluid. This will reduce the amount of work done by the heart and prevent heart failure.

If the indomethacin does not work, if the baby is too young to be able to be prescribed this medication, or if the medication cannot be used because of the baby's other medical problems, then the ductus may need to be closed surgically. The surgeon will tie off or clamp shut the ductus through a small incision in the baby's chest, a procedure that takes about an hour. Although surgery can be scary for parents to contemplate, be assured that the PDA surgery is routine and very safe. Once the PDA is fixed, there are no long-term effects to worry about.

(Above explanation is quoted from The Premature Baby Book of the Sears Parenting Library, by Sears, Sears, Sears, & Sears).


It has already been determined that Truman is going to need to have the surgical procedure performed on him, but we don't yet know exactly when that will be. On Sunday, August 13th he is supposed to receive a second echo to confirm the first one he had, prior to the scheduling of the surgery. We will keep you all up to date here.

--Ben