There are a few questions I would ask first before answering.
1. Is the catheter infected prior to the exchange? Is there a tunnel track infection present and/or positive blood cultures?
2. Are you exchanging over a wire?
3. How is the radiologist placing a catheter if he does not touch the original catheter?
If there is a tunnel infection present, you will need to change the tunnel and not go over a wire. It will be like a newly placed catheter. You don't want to place a new line into an area that already has an infection.
Secondly, if the patient has positive blood cultures, you should have the patient receive dialysis then pull the catheter. Give the patient at least 48 hours on antibiotics and be catheter free. If this is impossible, place a temporary femoral line during that time and then on the 3rd day place a tunneled catheter.
This is what we do if there is no signs of infection and will be exchanging over a wire.
1. The catheter dressing is removed and the skin and catheter are cleaned with adhesive remover and all adhesive is removed.
2. The heparin is removed.
3. The patient is then taken to the procedure room.
4. The scrub tech puts on sterile gloves. The entire skin, neck, chest area and the catheter itself is chlora-prepped. The caps are then removed. The hubs are then chlora-prepped, since you will be putting a guidewire down one of your lumens. We use a minimum of 2 chlora-prep scrubs and more if needed.
5. Once this area is prepped, a sterile towel is laid on the patient's chest and the catheter lays on this. Then the patient is covered with a sterile drap and we are ready to do the exchange.
6. Both the doctor and scrub nurse don 2 sets of sterile gloves. Once the wire is in position and the old catheter is removed, the one set of gloves are removed (the dirty ones that touch the old catheter). Now you still have clean sterile gloves on. The wire is then cleaned with betadine. Now you can place the new catheter over the wire.
I hope this helps. By using this technique, our outcomes are infection free!