What are the different dialysis access types?
There are 3 different access methods that allow dialysis:
- Central catheter
- AV fistula
- AV graft
Regardless of which type of access is used, the lifespan of the access is jeopardized by
Ruling out these complications via monitoring is necessary on a continuing basis.
The usefulness of dialysis access is dependent on its patency, and any of the above three complications can interfere with or completely eliminate the patency that the access requires. Patients can check for a “thrill,” which is a palpable sound–the tactile perception of circulatory turbulence–within the dialysis access. Absence of a thrill indicates blockage from stenosis or thrombus.
Central venous catheter
A central catheter is not recommended for long-term use due to its risk of infection, which can be identified by evaluating leukocytosis with a complete blood count and differential and with periodic blood cultures.
In the arteriovenous access methods, thrombosis and stenosis can jeopardize the AV access point. In both AVF and AVG, testing for hypercoagulability can be done with blood tests that evaluate clotting capabilities. Repeat coagulations studies are warranted in high-risk graft patients undergoing anticoagulation therapy.
Endogenous AV fistula (AVF)
After creating an endogenous AV fistula, its maturity for use can be accessed via imaging studies such as ultrasound. Stenotic lesions, thrombosis, or aneurysm formation that threaten the lifespan of a usable AVF are also evaluated via ultrasound.
Stenosis, thrombosis, and pseudoaneurysm (defects due to repeated cannulation) are also evaluated via ultrasound.
It is the indwelling central venous line that poses the greatest risk of infection. Nevertheless, the AV methods are not immune and may require blood work to rule out signs of infection, such as elevation in WBC or positive blood cultures.