Thoraco-amniotic Shunt (TAS) for fetal hydrothorax
This is a procedure that can be offered when there is a fetal pleural effusion: a build up of fluid in the space between the membranes surrounding the fetal lungs (pleural cavity). A build up of fluid in the cavity around the lungs can result in elevated pressure in the fetal chest, which can lead to underdevelopment of the fetal lungs and can lead to heart failure which makes the unborn baby very unwell (hydrops).
One way to treat pleural effusion is to remove the fluid using a special needle. The aim is to improve the circulatory situation of the baby and relieving the pressure in the chest. If the fluid builds up again, a special tube (thoraco-amniotic shunt, or pleuro-amniotic shunt) can be inserted; to try to continually drain the fluid in the chest. The procedure is performed under direct ultrasound vision. After an injection of antibiotics (to minimise the infection risk) and local anaesthetic, the fetal medicine specialist will introduce a needle is inserted through the woman’s tummy into the womb, and through the baby’s chest into the chest cavity. A flexible tube is moved down the needle and positioned between the pleural cavity and the amniotic fluid around the baby. The shunt is removed or replaced as soon as the baby is born.
Because this is an invasive procedure, there are associated risks and your fetal medicine doctor will talk through your different management options for pleural effusion such as waiting and seeing (in cases in which the fluid spontaneously resolves), repetitive thoracocentesis (drainage), and shunting (leaving a tube on continuous drainage). There are risks of failure to drain the chest, need for repeat shunt, displacement of the shunt into the chest, trauma to the unborn baby, premature delivery, sepsis and fetal death despite the shunt.