AV Fistula, AV Graft, and Catheter Comparison
Key Takeaways
- AV fistulas use the patient's own vessels and are assessed for thrill, bruit, skin integrity, and maturity before cannulation.
- AV grafts use synthetic material, can clot or become infected, and require careful site rotation away from problem areas.
- Central venous catheters avoid needle cannulation but carry high infection, air-entry, flow, and clotting risks.
- Any absent thrill or bruit, drainage, redness, swelling, severe pain, or cold/numb hand requires escalation before access use.
Comparing Hemodialysis Access Types
A vascular access is the route used to move blood from the patient to the extracorporeal circuit and back. The three common access categories on CCHT questions are AV fistula, AV graft, and central venous catheter.
| Access | What it is | Exam focus |
|---|---|---|
| AV fistula | Surgical connection of the patient's artery and vein | Listen and feel for bruit and thrill, inspect skin, protect the access arm |
| AV graft | Synthetic tube connecting artery and vein | Rotate cannulation sites, watch for clotting, infection, and swelling |
| Catheter | Tube placed into a central vein | Strict asepsis, closed caps and clamps, infection and air-entry prevention |
An AV fistula usually has the lowest infection risk when mature and functioning, but it still can fail. A missing thrill or bruit, new severe pain, cool hand, numbness, redness, drainage, or swelling is not a routine finding. The exam-safe response is to stop before cannulation and report according to facility policy.
An AV graft may be easier to identify by its loop or straight path, but it is not a shortcut access. Avoid cannulating near anastomoses, scabs, infection, aneurysmal areas, or recently infiltrated sites. Repeated use of the same small area can damage the access and increase complications.
A catheter may be used when an AV access is not available or not ready, but it is a central line and must be handled as high risk. It is not cannulated with fistula needles. The technician's role is to follow catheter policy exactly, protect the sterile closed system, and escalate abnormal findings.
Before cannulating a patient's AV fistula, the technician cannot hear a bruit or feel a thrill. What is the safest next action?
Which access type generally creates the highest infection-control concern because it is a central line?
A graft site has new redness, warmth, tenderness, and a small amount of drainage. What should the technician do?