An External Ventricular Drain (EVD) is a temporary device that allows drainage of excess fluid, such as Cerebral Spinal Fluid (CSF), from the brain and spine, via a thin tube that goes out of the head and into a collection bag outside the body. This device is attached to a mobile pole which allows your child to move about, if observed by nursing or medical staff.  

What is CSF?

CSF is a clear, colourless body fluid that cushions the brain and spinal cord and helps remove waste products produced by the brain. CSF is produced within the interconnecting cavities of the brain known as ventricles. It is then circulated around the brain and spinal cord before being reabsorbed.

Why does my child need an EVD?  

An EVD may be needed due to infection or raised intracranial pressure (ICP). Raised Intracranial Pressure occurs when there is an increased pressure in the skull caused by:

• a build-up of fluid
• swelling of the brain
• bleeding

 An EVD is inserted to help remove excess CSF to reduce pressure in your child’s head.

The length of time that your child will need an EVD will vary and the treating neurosurgeon will decide when it is ready to be removed, based on your child’s condition. While the EVD is in place your child will need to remain in hospital.

What to expect with EVD use?

Prior to your child’s surgery for the insertion of an EVD, the surgeon will visit you to explain the operation, and discuss any questions you may have. Timing of each surgery case may vary, depending on if it’s an isolated EVD insertion or if additional surgery is also required. Your neurosurgeon will discuss this with you prior to obtaining your consent.

The drain will be inserted during an operation under general anaesthetic. The surgeon will feed the tube under your child’s skin into the ventricles within the brain to enable drainage of the CSF. The drain may exit from your child’s head or tummy. Where possible, the surgeon will discuss the exit site with you before the operation.

Once the EVD is inserted, it will need to be levelled. This means that the EVD is positioned at the same horizontal level as your child’s ventricles within their brain. The EVD will be levelled using a laser pointer to your child’s ear (when lying on their back) or between the eyebrows (when lying on their side). Re-levelling needs to occur every time your child moves.

It is critical that your child does not sit up or move positions without informing the nursing staff first.

The EVD will be checked every hour by nursing staff who will look at how much CSF has drained, that the drain is levelled correctly, that your child’s EVD dressing is dry, and that the EVD is not blocked. Your child’s neurosurgeon may decide to change the level of the EVD depending on your child’s neurological condition and the amount of CSF that is draining out every hour.

The EVD may need to be turned off so that your child does not drain too much CSF. Over drainage can be dangerous as it may cause the ventricles to collapse.  However, your nursing team will assess this in their hourly checks.

The nurse will also regularly check your child’s neurological condition, which will mean waking your child up regularly overnight. If your child is experiencing headaches, nausea/vomiting, double/blurred vision or seems more irritable than usual, please let your nurse know immediately.

How is the EVD removed? 

The EVD is removed by a doctor from the neurosurgery team. This may be done either on the ward, or in theatre if further surgery is required. When removed on the ward, the procedure may be carried out either in the patient’s room or in the treatment room, depending on you and your child’s preference. The removal of the EVD is completed under sterile conditions with pain relief, distraction and staff assistance.

Once the EVD is removed, you should monitor your child’s wound site to ensure the dressing remains dry and intact. If you notice any signs of leaking from the dressing site, please inform your bedside nurse.

After your child’s EVD is removed, a permanent method of draining CSF is sometimes needed. This device is known as a shunt. If your child is likely to need a shunt, the neurosurgeon will discuss this with you.

Care at Home

In order to prevent infection, your nurse will provide wound education prior to discharge. 

Key points to remember

• An External Ventricular Drain (EVD) is a device that allows drainage of excess fluid from the brain and spine.
• An EVD may be needed for infection or raised Intracranial Pressure (ICP).
• Your child must not sit up or move positions while the EVD is connected, without informing nursing staff first.
• Parents are not to touch the EVD.

For more information

Please ask your nurse or the neurosurgery team if you have any questions. 

• Neurosurgery Department
• Cockatoo Ward

Developed by The Royal Children's Hospital Cockatoo Ward and Neurosurgery Department. We acknowledge the input of RCH consumers and carers.

Reviewed June, 2021. 

Kids Health Info is supported by The Royal Children’s Hospital Foundation. To donate, visit www.rchfoundation.org.au.