Patent ductus arteriosus (PDA)
The ductus arteriosus is a blood vessel that connects the pulmonary artery (main vessel supplying the blood to the lungs) to the aorta (main vessel supplying the blood to the body). This connection is present in all babies in the womb, but should close shortly after birth. In some babies, especially in those born prematurely, this vessel may remain open. This is called a patent or persistent ductus arteriosus.
What causes a baby to have a ductus arteriosus?
In the womb, the mother’s placenta provides oxygen for the baby and the ductus arteriosus allows blood to bypass the lungs. After birth, the baby must use their lungs to take in oxygen and get rid of carbon dioxide. To achieve this, the blood flows to the lungs and the ductus arteriosus closes. The ductus arteriosus normally closes shortly after birth. However in some babies, especially premature babies, it can remain open or even reopen.
How will it be detected?
A heart murmur will be heard by the doctor examining the baby.
The team looking after the baby may have suspected a PDA as the baby had difficulty coming off the ventilator or CPAP machine. The baby will then have had an echocardiogram to confirm the diagnosis.
What happens if this blood vessel stays open?
A patent ductus arteriosus increases the blood flow to the lungs. This can make it harder for the baby to breathe and come off the ventilator.
The heart also has to work harder to pump blood around the body, which can lead to heart failure (which is completely reversible). Many babies with a PDA will have been kept on reduced fluid intake and given diuretic medicines to try to treat fluid overload caused by heart failure.
To try to close the connection, the baby may have been given medication (often a non-steroidal antiinflammatory drug such as ibuprofen). Sometimes medication is unsuccessful or not appropriate and a surgical closure might be needed.
How is a patent ductus arteriosus surgically repaired?
Patent ductus arteriosus is surgically closed in an operation under general anaesthetic.
What happens before the operation?
The baby will be moved to the Neonatal Intensive Care Unit (NICU) at GOSH by a neonatal transport team. Accommodation can be provided for parents during their baby’s stay on the NICU. The baby will continue to receive the care they need in NICU.
To assess a child, various tests will be performed:
- Chest x-ray
- Blood tests
We will ask that all parents leave the unit when the operation is in progress.
What does the operation involve?
The operation is usually carried out in NICU while the baby is under general anaesthetic by a cardiothoracic surgeon and anaesthetist. If this is not appropriate and the baby needs to leave the unit to go to the operating theatre we will discuss the reasons with the parents.
During the operation the surgeon will make a small cut underneath the baby’s left armpit, in between the ribs. A metal clip or suture is placed around the PDA closing it and the wound closed.
The operation usually takes around one hour
Are there any risks?
All operations carry a small risk which will be fully explained by the cardiothoracic surgeon taking consent. In general, the main risks include bleeding, infection, chylothorax (build up in the chest cavity of chyle, a milky fluid that is made when the body digests fat) and pneumothorax (air in chest cavity).
There is also a small chance that the lung could be damaged when it it moved aside to attach the clip to the PDA. Other rare risks include damage to the nerves in the larynx (voicebox) which may last for a while. As with any surgical procedure, there is a very rare risk of death.
What happens afterwards?
The parents will be able to visit their baby as soon as the surgery has finished. The baby will continue to need help with breathing so will remain connected to a ventilator. We will give the baby medicines to ensure they are comfortable and free from pain.
Occasionally there may be a tube (chest drain) inserted. If the baby requires a chest drain we will explain this to the parents.
To assess the baby’s progress after the operation, we will repeat some tests as carried out previously:
- Chest x-ray
- Blood tests
The baby will not usually need a follow up appointment by the cardiologists or cardiac surgeons at GOSH.
Progress back on local NICU
While some babies take a little time to recover from the PDA closure, most recover quickly. Some babies may need more help from the breathing machine for a few days as their left lung is moved out of the way during the operation so will need time to recover. Generally after the duct closure, the baby’s breathing, tolerance of feeds and growth will increase.