Patent Ductus Arteriosus

Patent Ductus Arteriosus

Also known as PDA this condition is fairly common in preterm babies.  In babies born less than 28 weeks gestation the incidence is as high as 60% then this incidence decreases to 20% in preterm births older than 32 weeks gestation.  For term babies the incidence is a mere 0.02%.  In most situations the PDA will close within the first 3 days of life.  This condition can cause significant issues in preterm babies if not treated properly.

First it is important to understand what a PDA is and how it affects other systems in the body.  Patent means "open" and the ductus arteriosus is a vessel that is vital in fetal blood circulation.  Before birth this vessel connects two arteries in the body together, the aorta and the pulmonary artery.  The aorta is an artery that carries blood away from the heart after it has been oxygenated to the rest of the body.  The pumonary artery is similar in that it is a vessel that carries blood however the blood it carries does not contain high oxygen levels since it is carrying the blood to the lungs to be oxygenated.  During fetal development the baby gets oxygenated blood from mom therefore the lungs are bypassed while they continue to develop.  Typically the ductus arteriosus closes shortly after birth when the lungs are now used for oxygenation.  However, in some instances it remains open.  This causes oxygen rich blood from the aorta to mix with oxygen poor blood from the pulmonary artery.


Taken from: http://www.nhlbi.nih.gov/health/health-topics/topics/pda/

A PDA in a preterm baby who already has immature lungs can cause worsening shortness of breath, or require more work to breath.  Sometimes additional oxygen or ventilator support is necessary while the condition is corrected.

Correcting a PDA can be done in a variety of ways.  These include:

• Conservative treatment - Waiting for the PDA to close itself.  It has been found that upwards of 70-90% will close within 3 days of birth if left alone or with adjustments to ventilator settings.

• Medicines - The use of Indomethacin or ibuprofen have been shown to be a first line medicine to close the PDA.

• Surgery - If all other treatments fail a surgical ligation can be performed in which the vessel is tied off to prevent the flow of blood through the vessel.

The medical team will advise you that it is important to give the baby a chance to close this vessel themselves since medicines and surgery have potential complications that could further complicate the already difficult course that babies have in the NICU.  How aggressively the PDA is treated is primarily dependent on the problems that it is causing for the respiratory system.  Another important note about a PDA is that when it closes it can still re-open so the medical team will pay close attention to the heart exam and watch the baby clinically to ensure no unexplained symptoms are occurring.

My above explanation is just brushing the surface so for more detailed information feel free to refer to the below reliable sites.

http://www.nhlbi.nih.gov/health/health-topics/topics/pda/

http://emedicine.medscape.com/article/891096-overview#a0101

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2675417/