External Ventricular Drain or Shunt

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If too much fluid builds up in your child's head, this creates pressure that can be harmful, even life-threatening. External ventricular drains or external shunts are used for urgent removal of extra fluid from the brain to reduce the pressure. These drains are most often used for only a short amount of time.

What is an external ventricular drain (EVD)?

External ventricular drains are tubes that a doctor places in a part of your child's brain, called the ventricle, to remove extra fluid.

The tube passes through a small opening in the skull. The tube travels to a fluid space near a part of the brain called the ventricle.
The tube runs a short distance and exits through an opening in the skin (incision).
The tube drains extra fluid into a collection bag outside of the body.

The doctor may place a long tunneled external ventricular drain. In this type of drain, the tube runs under the skin for a longer distance (tunneled). The tube comes out of the chest or stomach area (abdomen), exiting into a collection bag.

What is an external shunt?

If your child has an external (externalized) shunt, one end of the tube lies near the brain, and the other exits outside the body. The fluid goes into a collection bag.

Why are external drains and shunts needed?

Your child might need an external drain or shunt if they have:

Hydrocephalus — Your child's body makes a fluid known as cerebrospinal fluid (CSF). CSF flows within and around the brain and spinal cord. CSF prevents injury and keeps the brain healthy. If too much fluid builds up (hydrocephalus) and does not drain out properly, the brain pressure rises. This rise in pressure can hurt the brain and be life-threatening. If it suddenly gets worse, this is known as acute hydrocephalus.
Bleeding in the brain, an infection called meningitis, or a tumor that blocks the normal flow of CSF — These problems can cause fluid build-up in the brain and increase pressure.
An infected shunt — If your child started with a ventriculoperitoneal shunt, the doctor may move one end to treat an infection. The doctor may move the far end of the shunt tubing outside of your child's body. The procedure is known as "externalizing the shunt" and is always temporary.

Hospital care of an external shunt

If your child's bag has a system, their head and shunt system must stay in the correct position because:

An external system drains into a bag that is outside of their body.
If your child has an external ventricular drain, the collection bag needs to stay at a certain height, usually measured from their ear. Do not move the drainage bag or your child's bed without first asking the nurse or doctor. Moving either one makes fluid drain slower or faster than needed.
If your child has an externalized shunt, it is not as critical to keep the head and collection bag in a specific position, but follow the instructions given to you by your child's nurse.

Your doctor will pick the best position for your child's head and the shunt system. The nurse will:

Check the position of the shunt and your child's head
Make sure the bag is draining correctly
Check your child's health

Hospital staff will usually put a sign on the door to remind you not to move your child until you check with a nurse.

When to call the nurse

Call the nurse if:

The tubing gets disconnected or has a kink
Your child has a headache, feels sick to their stomach, or vomits
Your child has any of the signs listed below that the shunt is not working or infected. Call for help right away, day or night, as this can cause serious problems.

Warning signs of an external ventricular drain or shunt malfunction (not working)

Here are the warning signs that your child's external shunt is not working correctly.

Watch for these signs of shunt malfunction:

Fluid is not draining into the bag, or more fluid is coming out than usual.
The CSF fluid that comes out usually is clear but changes color. You might see a small amount of blood for several hours after your child gets an external shunt, but the fluid should stay clear after that. Colored CSF can be a sign of infection or bleeding inside the head.
The filter on the collection chamber gets wet. A wet filter will change how well the CSF drains into the bag.
If your child does an activity, check if the shunt tubing has pulled out of the skin, even a little bit. Do not try to push it back into your child's body.
The dressing looks wet, loose, or dirty
The shunt tubing breaks or leaks

Warning signs of a shunt infection

Bacteria (germs) can cause infection. The shunt may stop working if infected. Infection can cause pressure to rise and be life-threatening.

Watch for these signs of shunt infection:

A fever of 100.4 degrees Fahrenheit or more (38.0 degrees Celsius)
Redness or swelling of the skin along the path of the VP shunt
Pain around the shunt or tubing
Your child has a headache that gets worse, or they act anxious, irritated, or whiny (this may be the only sign of a headache in young children who can't talk).
Vomiting (throwing up) with little or no nausea (sick to their stomach)
Your child is not alert. If you cannot wake them up, tell your nurse right away.
You notice changes in their personality, such as an easy-going child who suddenly is hard to handle or does not act right

Key Points

An external drainage system is a plastic tube that drains excess CSF from the brain to a bag outside the body.
When too much fluid builds up, pressure can increase, which can be harmful and even life-threatening.
An externalized ventricular drain or shunt will allow CSF to drain and will keep the pressure inside your child's head normal.
Learn the warning signs that the shunt is not working or has become infected.
Get help right away if you notice any of these warning signs in your child.

For more information

See together.stjude.org for more information on the related topic Ventriculoperitoneal (VP) shunt.

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Reviewed: September 2022