Most children admitted to paediatric intensive care units (PICU) need to have medicines given to them into their veins using a narrow tube, so they do not need repeated injections. This tube is called a central venous catheter. Occasionally these catheters can cause infections in the blood and sometimes the tubes can get blocked by small blood clots.

Some intensive care units already use antibiotic or heparin coated catheters, but there is no proof that these are better than the standard ones at preventing infections. Most of the PICU's in this country use standard lines. The only way to find out for certain is to compare children who are given antibiotic or heparin coated catheters with those who are given standard ones in a clinical trial. Because we do not know which type of catheter is best, the type of catheter each child receives in the study will be decided randomly by chance.

Each child in the trial will have the same chance of getting any of these three catheters:

• Standard central venous catheter (not coated).
• Heparin coated central venous catheter. Heparin is a medicine that can stop blood from clotting and might stop the tubes being blocked and infections in the blood.
• Antibiotic coated central venous catheter. Antibiotics can be used to kill bacteria which cause the infections.

The aim of this study is to see how the three types of catheters compare in reducing the amount of blood infections in children. We will also look at the costs involved. We hope to recruit 1200 children in the UK over 2 years. We hope that the information we get from this study will guide policy about purchasing impregnated Central Venous Catheters across the NHS and thereby improve treatment for children in the future.