A central line is a long, hollow tube made from silicone rubber. They are also called skin-tunnelled central venous catheters. Examples of some of the makes that are used are Hickman® or Groshong®. The central line is inserted (tunnelled) under the skin of your chest into a vein. The tip of the tube sits in a large vein just above your heart.

The space in the middle of the tube is called the lumen. Sometimes the tube has two or three lumens. At the end of the tube outside the body each lumen has a special cap to which a drip line or syringe can be attached. Sometimes there is also a clamp to keep the tube closed when it is not being used.

A central line can be used to give you treatments such as chemotherapy, antibiotics and intravenous fluids. It can also be used to take samples of your blood for testing. Central lines can also be used to give liquid food into the vein if your digestive system is not able to cope with food for any reason.

You can go home with the central line in place and it can be left in for weeks or months. This makes it possible for you to have your treatment without having to have needles frequently put into your veins. This may be very helpful if doctors and nurses find it difficult to get needles into your veins, or if the walls of your veins have been hardened by previous chemotherapy treatment.

Your central line will be put in at the hospital by a doctor or specially-trained nurse. Although a central line is usually put in under a local anaesthetic, a general anaesthetic is sometimes used.

Your neck will be checked for a suitable vein using a small ultrasound machine. The area where the line is to be inserted is cleaned with an antiseptic solution.

A local anaesthetic is used the numb the area. You shouldn't feel any pain when the tube is being put in, but you may feel a bit sore for a few days afterwards.

A small cut is made in the skin near your collarbone and the tip of the tube is threaded into a large vein. This is known as the insertion site. The tube is then pushed under the skin to reach the exit site. The exit site is the place where the tube comes out of your body (see diagram).

You will have a chest x-ray to make sure that the tube is put in the right place.

The position of the exit site will vary from person to person. You can ask the person who is going to put in the central line to show you where on your chest the exit site is likely to be.

When the tube has been put in you will have dressings covering the insertion and exit sites. For a few days you may have some pain or discomfort where the tube has been tunnelled under the skin. A mild painkiller such as paracetamol will help to ease this.

There is a small 'cuff' around the central line which can be felt under the skin just above the exit site. The tissue under the skin grows around this cuff over a period of about three weeks and holds the line safely in place. Until this has happened you will have a stitch holding the line in place.

When the central line is not being used there is a small risk that it may become blocked. To stop this happening a small amount of fluid is 'flushed' into the line using a syringe. This is usually done once a week. The caps or bungs at the end of each luman should also be changed every week. The exit site will also need to be cleaned once a week to reduce the risk of infection. If you have a dressing on the site it will need to be changed once a week.

The nurses at the hospital may teach you how to do this for yourself if you feel able to, or a district nurse can do it for you at home.

Infection

It is possible for an infection to develop either inside the central line or around the exit site. You should contact your hospital doctor or nurse if:

• the exit site becomes red or swollen or painful
• you notice discoloured fluid coming from it
• you develop a temperature.

You will be given antibiotics, but if these do not clear the infection from the line it may have to be removed.

Blood clots

It is possible for a blood clot (thrombosis) to form in your vein at the tip of the line. If a clot does form, you will be given some medication to dissolve the clot and your line may have to be removed.

Signs of a blood clot around the central line include swelling, redness and/or tenderness in the arm, chest area or up into the neck (on the same side as the central line). You should also contact your hospital doctor or nurse immediately if you develop any shortness of breath or tightness in your chest.

Air in the central line

No air must be allowed to get into your central line. The clamps should always be closed when the line is not in use. The line must not be left unclamped when the caps (bungs which are at each end of it and stop air from passing through it) are not in place. Groshong lines do not have clamps, they have a special valve inside the line instead.

Break or cut in the line

It is important that you do not get a break or cut in the line. Do not use scissors near the line and only use the clamp on the thicker, strengthened part of the line.

It is uncommon to get a cut or split in the line, but in the unlikely event of this happening try to clamp or tie your line immediately above the break (so its sealed between the split and where the line comes out of your body - the exit site). Call your hospital as soon as possible. The nurses may be able to repair the line, but if this can't be done, the line will be removed.

When you no longer need the central line it will be taken out. A doctor or nurse will do this for you, usually in the outpatients department. This procedure should take about 30 minutes. You will not need to have a general anaesthetic when the central line (catheter) is removed.

You will be asked to lie on a bed. The chest is cleaned with antiseptic. The area around the cuff is numbed with local anaesthetic. A small cut is made to gently release the cuff and the line is then removed slowly. This can feel uncomfortable, but it should not  painful.

A dressing will be put over the exit site and you will be asked to remain lying down (for about 10 minutes) until it is certain that there is no bleeding.

This section has been compiled using information from a number of reliable sources including:

• Guidelines on the Insertion and Management of Central Venous Access Devices in Adults. Bishop et al. International Journal of Laboratory Haematology, 2007.
• Cancer and Its Management (4th edition). Souhami and Tobias. Oxford Blackwell Scientific Publications, 2003.
• Cancer - Principles & Practice of Oncology (8th Edition) DeVita,V et al. Lippincott, Williams & Wilkins, 2008.
• The Chemotherapy Source Book (4th edition) Perry, MC . Lippincott, Williams & Wilkins, 2008.
• Central Venous Catheters - ultrasound locating devices NICE - National Institute for Health and Clinical Excellence, 2002.

For further references, please see the general bibliography.

Hickman and Groshong are registered trademarks of C R Bard, Inc or an affiliate.