Central Venous Access Devices
Children being treated for cancer or blood disorders often require multiple intravenous medications, chemotherapy, blood transfusions and fluids during the course of their treatment. Intravenous cannulas are a short term solution and for many children are a painful and unpleasant experience. As most treatment protocols require regular intravenous access over a long period of time, the oncologist or haematologist may recommend a Central Venous Access Device (CVAD) is inserted. The great advantage to the child is a CVAD eliminates the need to frequently insert needles into their veins.
A child may require a CVAD for the following purposes
- Long term chemotherapy
- Bone Marrow Transplant
- Intravenous fluids, medications or nutrition
- To obtain samples of blood for testing
CVADs should last the duration of the child’s treatment plan (up to two years in some cases) barring complications such as infection, blockage and dislodgement.
There are two main types of CVADs – your child’s specialist will discuss with you which CVAD is best suited for their treatment needs.
Central Venous Line (CVL)
- A long hollow tube made from silicone rubber and the end of the tube sits outside the body, to which a drip line or syringe can be attached.
- The most common type used at Sydney Children’s Hospital, Randwick (SCH) is the “Hickmans” line and are often referred to as a Hickmans catheter.
- Insertion of a CVL is done while the patient is under general anaesthetic, a small cut is made in the skin near the collar bone and the tip of the tube is inserted into a large vein to a point just above the heart. The remainder of the tube is then tunnelled under the skin to reach the exit site (the place where the end of the tube comes out of the body). A chest X-Ray is performed to ensure correct positioning. There is a small cuff around the CVL that 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 3-6 weeks and holds the line safely in place. A general anaesthetic is also required to remove a CVL.
- When not in use, a CVL must be flushed weekly with a small amount of fluid with heparin (a drug to stop the blood clotting) inside the tube. The exit site must also be cleaned and dressing replaced once a week to reduce the risk of infection. The site must remain clean and dry so therefore swimming or deep baths are not allowed.
Totally Implantable Device (TID – commonly known as a port-a-cath)
- A port-a-cath is a long silicone rubber tube (silastic catheter) attached to a reservoir portal which has a silicone membrane on top.
- A port-a-cath is inserted in the same way as a CVL except the catheter does not exit the chest wall but is attached to the portal reservoir which sits under the skin. It can be seen as a small bump underneath the skin and nothing else is visible on the outside of the body.
- In order to use the port, a specialised needle is put through the skin into the port. The needle is then attached to tubing to give the medications or fluid. Once each treatment episode is completed the needle may be removed.
- When the needle is removed after each treatment, the port is flushed with a heparin solution (to stop the blood clotting in the tube) to prevent blocking.
- If the port-a-cath is not in regular use, it needs to be flushed with the heparin solution every 4 - 6 weeks. A dressing is not required as the skin acts as a protective barrier.
- Port-a-caths are less likely to break or become infected than CVLs because they are completely concealed beneath the skin. Swimming, bathing/showering is also permitted.
- A port-a-cath may remain in the body for years if necessary, unless complications such as infection or blockage occur. In this case it may need to be removed (under general anaesthetic).
Care of the Central Line
The following potential complications must be treated urgently if they occur:
- Infection – you should contact the Hospital if the exit site of a CVL or the skin around the port-a-cath becomes red, swollen or painful OR if your child has a temperature.
- Clots/blockage – it is possible for a blood clot (thrombosis) to form in the vein around the tip of the line and it needs to be treated ASAP.
- Dislodgement – It is possible for the CVL to accidentally fall out or be pulled out. Put pressure on the exit site immediately and contact the Hospital.
- A cut or break in the line – if the CVL line does get cut or split, try to clamp it between the split and the exit site (where it comes out of the body) and contact the Hospital immediately.
Please note: Nursing staff will provide extensive education in regards to caring for your child’s CVAD at home.