In this section
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.
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.
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:
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.
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
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
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.
In order to prevent
infection, your nurse will provide wound education prior to discharge.
Please ask your nurse or the neurosurgery team if you have any questions.
Why do the nurses need to take daily samples of the Cerebral Spinal Fluid (CSF)?
The nursing staff will take a sample of the CSF usually once a day. This is to ensure that there is no infection in the CSF. One to two nurses will complete this pain free procedure and collect approximately 1ml of CSF. Your child will be on antibiotics while the EVD remains in place to avoid infection.
How do I care for my child with an EVD?
You will be able to care for your child and help them with many of their usual activities, with assistance from their nurse. However, you will need to speak to the nursing staff before moving your child (please feel free to press the nurse call button). For the safety of your child please, do not touch the EVD.
Will my child feel any pain related to the EVD?
Your child may feel some discomfort at the insertion site initially but that will decrease with time. However, the hourly and daily cares of the EVD will not be painful.
Developed by The Royal Children's Hospital Cockatoo Ward and Neurosurgery Department. We acknowledge the input of RCH consumers and carers.
Reviewed June, 2021.
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