A tunnelled central venous catheter (also called external catheter or central line) is a long, flexible tube. One end of the catheter is placed in or near the right atrium of the heart and the other end is outside the skin of the chest. The tube tunnels under the skin of the chest, enters a large vein near the collarbone and threads inside the vein into or near the right atrium of the heart.
The person feels no pain as chemotherapy drugs, blood transfusions or intravenous (IV) fluids are put into the end of the catheter hanging outside the body. Blood can be drawn from the end of the catheter in or near the heart.
Tunnelled central venous catheters are sometimes referred to by their brand name. The 3 main types of tunnelled central venous catheters are:
When a tunnelled central venous catheter is used
A tunnelled central venous catheter is used when the:
- person needs intravenous (IV) access so they can receive fluids, transfusions or drugs for a long period of time (generally longer than 3 months)
- person needs many blood draws for lab tests
- More blood draws can be done with a tunnelled central venous catheter than with a peripherally inserted central catheter (PICC).
- peripheral veins are not large enough for a PICC
- small veins in the body can no longer be used for giving fluids or drugs
Benefits of a tunnelled central venous catheter
There are many benefits to having a tunnelled central venous catheter rather than a regular IV. The most important benefit is that it reduces the number of needle sticks. However, it is important not to tell children that having a tunnelled central venous catheter means they will never have to be “poked” again, since they may still need needle sticks for some blood tests.
A tunnelled central venous catheter:
- can remain in the vein for a long time
- is very secure in the vein
- reduces discomfort because the IV therapy can be given more easily
- prevents the “burning” sensation sometimes felt when getting drugs by other IV methods
How a tunnelled central venous catheter is placed
The tunnelled central venous catheter is placed in the operating room while the person is under general anesthesia.
- The doctor makes 2 small cuts (incisions) in the skin. One cut is made over the vein where the catheter will enter the body. The other cut is made where the catheter will come out of the skin.
- The tip of the catheter is inserted in the large vein near the heart and threaded into or near the right atrium.
- The rest of the catheter is tunnelled just under the skin and comes out on the chest or abdomen. There will be 15–25 cm (6–10”) of catheter outside the body.
- The doctor places a few stitches in the skin around the catheter to hold it in place.
- The incision over the vein is closed with a few stitches or pieces of tape.
- A dressing is placed over both incisions.
- A chest x-ray is done to confirm the catheter tip is in the correct position.
After a tunnelled central venous catheter is placed
There is a small cuff on the catheter just behind where it comes out of the skin. This may be felt as a small bump under the skin. Body tissue will heal into this cuff in about 3 weeks and hold the catheter in place.
The area may be tender for 1–2 days after the catheter is placed, but the soreness should disappear in a few days.
How a tunnelled central venous catheter works
When the person needs IV therapy, the IV tubing is connected to the end of the catheter outside the body. The fluid or medicine flows through the IV tubing into the catheter, then into the bloodstream. After treatment is over, the IV tubing is removed and a new cap is placed on the end of the catheter.
Possible complications of a tunnelled central venous catheter include:
- infection in the skin at the exit site or in the blood
- Even with the best care, infections are common with a tunnelled central venous catheter.
- People who have low blood cell counts for long periods of time are at risk of developing infections.
- The external line needs to be flushed often, which increases the chance of bacteria entering the catheter.
- Most infections are caused by the person’s own bacteria.
- To help avoid an infection:
- Keep the exit site clean and dry.
- Wash hands every time the catheter is flushed or the dressing is changed.
- Call the doctor if there is any redness, tenderness or fluid leaking from the exit site.
- Some infections can be treated with antibiotics without removing the catheter. Sometimes it must be removed.
- blood clots in the catheter or the vein
- Even with excellent daily care, some tunnelled central venous catheters develop blockages or clots.
- If the catheter becomes blocked with a blood clot, the catheter may be flushed with a drug to try to dissolve the clot.
- Sometimes the catheter may be removed.
- A blood clot in the vein at the tip of the catheter can block blood flow through the vein and cause pain and swelling in the neck, face, chest or arm.
- An x-ray procedure, called a linogram or a Doppler ultrasound, may help the doctor confirm the presence of a clot.
- the catheter breaks outside the body
- Breaks in the line do happen, but they are very rare.
- They can usually be repaired without removing the catheter.
- the catheter cuff comes out from under the skin
- The catheter is almost always removed.
- the tip of the catheter moves out of the correct position in the vein
- The catheter must be removed.
While a catheter is in use
While the person receives an IV solution through the catheter:
- The end of the catheter is attached to plastic tubing that runs through a small machine (IV pump), which will pump the solution into the vein.
- The person does not need to stay in bed. A child may be held or be up out of bed.
- The part of the catheter outside the body will be coiled on top of the dressing and covered with tape to prevent any pulling or strain on the catheter.
- Be careful that the IV tubing does not get pulled.
- Let the nurse know immediately if any part of the catheter comes out from under the tape so that it can be secured.
Caring for a tunnelled central venous catheter
A tunnelled central venous catheter requires special care to prevent infection and blood clots. The site where the catheter exits the body must be cleaned often (every other day) and a fresh, sterile dressing needs to be applied and taped in place. The site should be checked often for redness, swelling and drainage.
An adult or older child will be taught how to care for the catheter at home, including how to:
- change the dressing at the catheter exit site (usually done 3 times a week)
- flush the catheter with heparin (a medicine that prevents blood from clotting in the catheter)
- change the caps (usually done once a week)
- prevent and recognize catheter problems
The person may continue most normal activities while the catheter is in place. Showering or bathing is done with plastic or waterproof tape over the dressing. Swimming is strongly discouraged.
Removing a tunnelled central venous catheter
A catheter is removed when IV therapy is no longer needed or if there is a problem with the catheter. A local anesthetic is used to numb the skin, or the person may be sedated or given general anesthesia. If the catheter is removed due to a complication and IV therapy is still needed, the doctor can usually place another catheter at a different site. Sometimes the healthcare team will wait a few days before placing a new catheter so that an infection can be treated.
When to call the doctor
Call the doctor if:
- there is any redness, tenderness, swelling or drainage at or near the catheter exit site
- the person has a fever, aches or flu-like symptoms
- the catheter has moved
- there is swelling, tingling or pain at or near the catheter exit site
- you cannot flush the catheter with heparin
- the catheter breaks