To perform CRRT therapies a special tubing set is used. In developed countries the tubing set is sterile when received, used once, then disposed of. The tubing set may or may not have a hemofilter attached. Hospitals generally prefer having a hemofilter pre-attached to the set since it requires less set up by staff. Before use, the tubing set is attached to a control unit.
The tubing has colored stripes to help identify its purpose:
- Red striped tubing is the access line, it moves blood from the patient to the hemofilter.
- Blue striped tubing is the return line, it is used to convey blood from the hemofilter back to the patient.
- Purple striped tubing is the replacement fluid line, it moves replacement fluid into the access (red striped) or return (blue striped) line.
- Green striped tubing is the dialysate line, it moves the dialysate from the source into the hemofilter.
- Yellow striped tubing is the effluent line, it removes the effluent from the dialyzer into a waste or effluent bag.
Other features of a typical tubing set include:
Pressure Sensors (shown right) which are used to measure the pressure of the fluid in the tubing. The pressure sensor shown at right is a pressure pod from a Prisma set. The pressure pod can clot more easily and it is harder to remove air bubbles from than straight through pressure types, however it is probably the most common pressure sensor in use.
Sample ports (shown left - sorry about the picture, I will try to get a better one soon) are used to take various fluid samples easily. Having a sample port built into the tubing set saves the patient from being stuck with a needle when a sample is required. The sample port shown on the left is from a Prisma set, it requires a needle to take a sample. Many places prefer needleless sample ports and they are becoming more common as there is less chance for hospital staff to stick themselves accidentally. Each set generally has multiple samples ports, at least one in the access portion and one in the return portion of the tubing.