3.1 Cannulation skill:
Staff should be appropriately trained and observed for technical mastery before cannulating any AV access. Only those with said technical mastery should be allowed to cannulate a new fistula. A protocol for minimizing vessel damage should be used for cannulation failure. Recannulation should be attempted only when the cannulation site is healed and the vessel is assessed to be normal and appropriate for cannulation. Heparin management should be reviewed on a case-by-case basis to minimize postdialysis bleeding.3.2 Self-cannulation:
Patients who are capable and whose access is suitably positioned should be encouraged to self-cannulate. The preferred cannulation technique is the buttonhole.3.3 Buttonhole:
Patients with fistula access should be considered for buttonhole (constant-site) cannulation. (See protocol in CPG 3.)3.4 Elevation of arm for swelling:
The AVG access arm should be elevated as much as possible until swelling subsides, which may take as long as 3 to 6 weeks. Increase in symptoms requires urgent evaluation.
Data from DOPPS599 show that a functional fistula should have an outflow vein that can be successfully cannulated 1 month postoperatively. The previous KDOQI Vascular Access Guidelines recommendation of 3 to 4 months after access creation was opinion based as a result of anecdotes of early cannulation failure with resulting tissue infiltrations and vessel damage. Consideration should be given to marking, with the aid of ultrasound, veins that are difficult to see and feel, with accompanying measurements of the vein margins to prevent aspiration of clots when the needle is placed too close to the vein wall.
Many centers have higher doses of heparin for catheter-dependent patients than for patients with subcutaneous access. New fistulae are more likely to bleed for a variety of reasons: infiltrations, patient and staff inexperience with hemostasis, and lack of clarity regarding when to reduce the heparin dose if a patient is using both a fistula and 1 lumen of the catheter.
There is growing evidence that buttonhole (constant-site) cannulation may be less likely to infiltrate, may be pain free for the patient, may help preserve the integrity of the outflow vein,244 and may be easier for patients to self-cannulate.