A. Pain and other disadvantages of AV fistula cannulation can be limited by using the so-called buttonhole technique.

B. Till present in our center catheters with cylindrical points are used for cannulation of AV fistulas with the rope ladder technique. One can hypothesize that a catheter with a bevel point might have some advantages such as a larger entrance area and less traumatic cannulation. The latter may influence pain sensation of the patients.

The above background information gives rise to the following investigational questions:

A. Buttonhole vs rope ladder technique

1. Is pain sensation different when using buttonhole cannulation as compared to rope ladder cannulation technique?

   Hypothesis:

   AV fistula cannulation by buttonhole technique causes less pain than cannulation by rope ladder technique.

2. Is the level of anxiety different when using buttonhole cannulation as compared to rope ladder cannulation technique?

   Hypothesis:

   AV fistula cannulation by buttonhole technique causes less anxiety than cannulation by rope ladder technique.

3. Is bleeding time different when using buttonhole cannulation as compared to rope ladder cannulation technique?

   Hypothesis:

   Bleeding time is shorter when using buttonhole technique versus rope ladder technique.

4. Is the number and severity of complications related to AV fistula cannulation different between buttonhole and rope ladder technique?

   Hypothesis:

   When using the buttonhole technique for AV fistula cannulation the number and severity of complications is less than when using the rope ladder technique.

   B. Rope ladder technique using catheters with cylindrical vs. bevel point

5. Is pain sensation different when using rope ladder cannulation catheters with cylindrical as compared to bevel point?

Hypothesis:

AV fistula cannulation using bevel point catheters causes less pain than cannulation using cylindrical point catheters.