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Cerebrospinal fluid (CSF) drainage system

Patient information A-Z

External ventricular drain (EVD)

Lumbar drain

Who is this leaflet for?

For those patients in the hospital with a newly inserted external ventricular drain (EVD) and / or lumbar drain.

What is it's aim?

To ensure that the patient and their relatives / carers are informed of the reasons for the EVD / lumbar drain insertion and the possible risks and side effects.

What is hydrocephalus?

Hydrocephalus is an abnormal (too much) collection of fluid in the head. The fluid is called cerebrospinal fluid, commonly referred to as CSF. The CSF is located and produced within fluid compartments of the brain called ventricles. The function of CSF is to cushion the delicate brain and spinal cord tissue from injuries and maintain a proper balance of nutrients around the central nervous system.

What are the causes and types of hydrocephalus?

In general, hydrocephalus can be caused by one or more of the following:

  • An obstruction or blockage in the CSF fluid flow
  • Overproduction of CSF (too much CSF being produced)
  • Under-absorption of CSF into the blood stream (too little CSF being absorbed)

How do we manage hydrocephalus?

During an acute case of hydrocephalus, the neurosurgeon will insert a temporary drainage system that works by using gravity. This can either be an EVD or lumbar drain depending on what causes the hydrocephalus.

Putting in an EVD is a temporary method of draining too much fluid from the brain. The EVD system uses a catheter (a thin plastic tube), which is placed in the fluid compartment in the brain via a hole done in the head through surgery. This is then connected to a drainage system outside the head.

A lumbar drain is a small flexible tube that is also a temporary drainage system, placed in the lumbar (lower) spine. The tube drains excess CSF that fills the fluid compartment of the brain and around the spinal cord. The flexible tube from the lower back is also connected to the drainage system.

Risks associated with CSF drainage

There is a high risk of infection. You and or your relatives should not touch any part of the drainage system at any time. You must not go out of the ward while you have the drain inserted. The specialist nurse will also need to check your vital signs (temperature, pulse rate, blood pressure and respiratory rate every two to four hours, depending on your medical condition. They will also perform a neurological observation (checking your ability to open your eyes, orientation and arm movement).

You have to maintain your posture at all times. If you need to change your posture, move, or transfer from bed to chair you must inform your nurse. The nurse will temporarily clamp your drain before you change position or when you move. This is to minimise the risk of over drainage (too much) or under drainage (too little) as the drain works by gravity.

Your nurse will check the status of the drain regularly, however, if you have any concerns in between the nurse’s visits please call them as soon as possible.

Contacts / further information

  • For immediate support please contact the nurse looking after you in the ward.
  • Hydrocephalus Clinical Specialist Nurse: Bleep 152 423

Privacy and dignity

Same sex bays and bathrooms are offered in all wards except critical care and theatre recovery areas where the use of high-tech equipment and/or specialist one to one care is required.

We are smoke-free

Smoking is not allowed anywhere on the hospital campus. For advice and support in quitting, contact your GP or the free NHS stop smoking helpline on 0800 169 0 169.

Other formats

Help accessing this information in other formats is available. To find out more about the services we provide, please visit our patient information help page (see link below) or telephone 01223 256998.

Contact us

Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge

Telephone +44 (0)1223 245151