Central lines (skin-tunnelled venous catheters)

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 other end of the line hangs out of your body, from the chest. The line will usually be sealed with a special cap or bung that can be attached to a drip or syringe. Sometimes there is also a clamp to keep the line closed when it isn't being used.

The space in the middle of the tube is called the lumen. Sometimes the tube has two or three lumens. This allows different treatments to be given at the same time. 

A central line can be used to give you treatments such as chemotherapy|, blood transfusions|, antibiotics and intravenous (IV) fluids. It can also be used to take samples of your blood for testing. This means that you won't need to have needles put into veins in your arms every time you have treatment. Central lines can also be used to pass 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.

A central line may be 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. It is also helpful if you don't like needles.

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 then 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 (the insertion site) and the tip of the line is gently threaded into a large vein towards the heart. The other end of the line is then tunnelled under the skin to reach the exit site. The exit site is the place where the tube comes out of your body.

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

The position of the exit site will vary. 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 line 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 it has been tunnelled under the skin. A mild painkiller such as paracetamol will help ease this.

When the central line isn't being used, there is a small risk that it may become blocked. To stop this from 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 lumen 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. To help reduce the risk of infection, an antibiotic patch may be put around the exit site.

The nurses at the hospital will teach you (if you feel able to), or a relative or friend, how to flush the line and change the dressings, or a district nurse can do it for you at home.

When you are at home, it is safe for you to have a shower or bath with your central line in place. Your nurse can give you waterproof covers to stop the line from getting wet.

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 the exit site
• you develop a temperature.

If an infection develops, you will be given antibiotics. If these don't clear the infection, or if the infection is serious, the line may be removed.

Blood clots

It is possible for a blood clot (thrombosis) to form in your vein at the tip of the line and you may be given medication to help prevent this. 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 can 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 or bungs aren't in place. Groshong lines don't have clamps – they have a special valve inside the line instead that stops air from getting into the line.

Break or cut in the line

It's important that you don't 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's 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 it's sealed between the split and where the line comes out of your body (the exit site). Call your hospital straight away. The nurses may be able to repair the line, but if this can't be done, it will be removed.

When you no longer need the central line it will be taken out. A doctor or specially trained nurse will do this for you, usually in the outpatients department. This procedure should take about 30 minutes. You won't usually need to have a general anaesthetic.

You will be asked to lie on a bed, and the chest is then 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 shouldn't be 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.