Patent Ductus Arteriosus (PDA) in Premature Infants
Arteries are blood vessels that carry blood from the heart to the rest of the body. “Patent” means open. “Ductus arteriosus” means arterial canal. So the patent ductus arteriosus (PDA) is an opening between two arteries. The two arteries are the pulmonary artery and the aorta. The pulmonary artery goes to the lungs. The aorta is the main artery that carries blood from the heart to smaller arteries. The PDA is a normal structure in the fetus. While in the womb, the baby doesn’t breathe. That means only a little blood needs to go to the baby’s lungs. The PDA allows blood to flow from the pulmonary artery to the aorta, bypassing the lungs.
When Is the PDA a Problem?
Normally, the ductus closes a few days after birth. This allows normal blood flow to the lungs. There, the blood picks up oxygen. The heart then pumps this blood through the aorta to the rest of the body. But if a baby is premature, the ductus may not close right away. In some cases this causes low blood flow to the lungs. Or, more often, blood flows backward through the PDA into the pulmonary artery. Too much blood then goes to the lungs. This causes pulmonary edema (fluid buildup in the lungs). This makes it hard for the baby to breathe. The heart also has to work harder.
How Is PDA Diagnosed?
The problem can be detected with an echocardiogram (ultrasound imaging test of the baby’s heart). In mild cases, there may be no symptoms. Or symptoms can include:
A heart murmur
Increase in the baby’s heart rate
Low blood pressure
Wide range of blood pressure
Worsening of breathing problems
How Is PDA Treated?
The ductus may close on its own, without treatment. If it doesn’t, treatments include:
Medication. Certain medications can constrict the artery, shrinking the duct and allowing it to close. The medication is given by IV over a period of a few days. During this time, the baby is monitored closely.
Surgery. This may be performed if the baby can’t tolerate the medication or if treatment with medication has not worked. During surgery, the surgeon clamps or ties off the opening in the blood vessel. The surgery doesn’t involve the heart muscle. This surgery has a high success rate and a low risk of complications.
What Are the Long-Term Effects?
Once the ductus is closed, there are no long-term effects.