Erfahrungen mit komplett implantierbaren Kathetersystemen bei immunsupprimierten Kindern — Ein Weg der systemischen Analgetikaapplikation

Summary

Fully implantable catheter systems are particularly suitable for use in children requiring long-term administration of antibiotics, cytostatics or analgesics, as these are precisely the children who are liable to panic attacks at the idea of injections.

There are various catheter systems that are suitable for children. In children with a body weight of at least 3 kg a catheter in the internal jugular vein can be used. Children under 6 years of age must be heavily sedated for the implantation, while older children can manage with a local anaesthetic.

For full-term and preterm neonates, the Silastic catheters designed by Shaw are particularly appropriate; these can be inserted with the flow from any peripheral vein by way of a 19-gauge butterfly cannula.

When full-term and preterm neonates have collapsed veins, e.g. in the presence of circulatory collapse, there is no way of avoiding a venous section for placement of a catheter system.

Umbilical vein catheters are suitable only for emergency use in the delivery room because of the ensuing risk of infection and the risk that portal vein thromboses may occur.

Percutaneous insertion of central venous catheter systems is an especially good approach for children undergoing long-term oncological treatments. Hickman and Broviac catheters are available for this application. Another catheter system that can be implanted in toto is the Thera-Port system (Baxter). Fully implantable catheter systems are inserted under a general anaesthetic.

The procedure is as follows:

• 1. The catheter system is filled with heparinized physiological saline solution.

• 2. The catheter tip is advanced carefully by way of the superior caval vein while progress is monitored on a video display.

• 3. Once a good position is reached the catheter is fixed in place by means of a vascular suture.

• 4. A subcutaneous pouch is then prepared for implantation of the port.

• 5. A precise connection must then be made between the distal end of the catheter and the outlet tube with the safety ring.

• 6. Permanent perfusion of the system is not necessary because of the heparin block.

A system of this type can even be implanted in the case of immunosuppressed children or children with coagulation disorders, providing adequate antibiotic protection or, if appropriate, thrombocyte substitution is instituted.

To avoid complications, loops and kinks in the tubing must be avoided, adequate subcutaneous support must be ensured for the port, and the system must be appropriately looked after by trained staff. Whenever blood is taken, the system must be well flushed with 0.9% saline solution immediately afterwards to remove any blood components.

The advantages of fully implantable catheter systems lie in the fact that the children do not need to be constantly connected to an infusion system, so that they can move about freely and they are more easily cared for. In addition, the absence of any part of the catheter outside the body means that the risk of infection is substantially lower with the fully implantable systems, as is the danger of catheter faults (which usually arise in the external part), and these children are not hampered by the presence of a dressing. In chronically ill children the catheter system can also be used for pain therapy and for building up to the dose of analgesic medication needed.