Cannulation Technique may Improve Fistula Survival

AV FISTULA

An AV fistula is the access of choice in patients starting dialysis. The use of AV fistula first is associated with less risk of infection which is a significant cause of morbidity and reduced survival in dialysis patients.

The technique used to cannulate a fistula is essentially the method used by the HD nurse to insert the venous and arterial needle into the fistula so that an adequate blood flow for the process of dialysis can occur.

However as noted by Van Loon et. al. "Little is known about cannulation of the vascular access (VA), such as the number of successful cannulation procedures, frequency of complications caused by cannulation, and VA failure."

The above investigators then went on to publish the results of a study conducted in incident dialysis patients who were followed for 6 months after the first successful cannulation with 2 needles.

Data collection included patient characteristics:

• Comorbidities


• Medication.

Vascular access characteristics:

• Type of VA and location


• Vein diameter


• Length of the cannulation route


• Maturation period.

The study took place between 2005 and 2007 in 10 Dutch dialysis facilities and ultimately included 120 patients.

For AV fistulas with a short cannulation route (small area for insertion of the needle) outcomes were negatively affected compared to those that had a longer area for cannulation.

Significant predictors of vascular access failure were previous use of central vein catheters and previous use of single needle dialysis.

The conclusion of the investigators was that "The present study demonstrated that during the first 6 months of a newly placed VA, a huge number of cannulation-related complications such as miscannulation, use of CVC, and SN dialysis are encountered."

So although fistula first is the logical choice in new patients, there are two important points that need to be noted. The fistula should be created in a manner that it is easily cannulated hence reducing cannulation errors and vascular access failure, according to this study the length of the cannulated limb of the fistula is very important in this regard.

Two cannulation technique is a wild card variable that is likely to vary widely from centre to centre based on differing levels of competence and experience between HD staff. The importance of cannulation has now been shown, the next step is standardizing techniques for cannulation and investigating access survival with different techniques and approaches to determine which technique or combination of techniques is best.