First cannulations of a new AV fistula: when, who and how

The first cannulations shape much of an arteriovenous fistula's future: the vein is still thin and fragile, and a hematoma can delay its use for weeks or stop it from maturing. This guide brings together what guidelines and studies say about when to start, who should cannulate, which needle and blood flow to use, how to progress and what to do if the first cannulation fails.

For professionals · Updated November 13, 2026 · 8-minute read

Why the first cannulations are critical

A newly matured fistula is not yet the thick, resilient vein it will be months later: its wall is thin, the usable segment is short and the skin has no marks from earlier cannulations. It is the highest-risk period:

• In a 5-year series, 43.5% of major infiltrations happened in fistulas less than 6 months old, versus 20.5% of controls [4].
• According to data cited by KDOQI, a single infiltration before the first two-needle cannulation is associated with 56% lower odds of the fistula maturing [3].
• In a UK study, failing to achieve six successful cannulations from the start of dialysis and using higher blood pump speeds in the first week were associated with worse fistula survival [5].

Every source reaches the same practical conclusion: first cannulations are not for learning. They are planned, done by the best cannulator and progressed slowly.

Is the fistula ready?

The decision to start cannulating belongs to the nephrology and vascular access team, based on the physical exam and, if in doubt, an ultrasound scan. The maturation criteria (diameter, depth and flow) are in the guide to the rule of 6s and fistula maturation. Before the first cannulation, check:

• The fistula map: type of access, course of the vein and direction of flow [1]. If you do not know it, ask for it or map it with ultrasound (see types of AV fistula).
• Today's exam: continuous thrill, soft bruit, the vein collapses when the arm is raised, intact skin and no hematomas (see cannulation technique).
• A straight, superficial segment long enough for the whole needle, away from the anastomosis and from bifurcations.
• A plan if it fails: who the second person is, whether the patient has a catheter to dialyze today, and what will happen to the fistula.
• An informed patient: what will be done, that it may be more uncomfortable, and to speak up about pain or swelling.

When to start: what the evidence says

The Spanish GEMAV guideline recommends not cannulating a native fistula before 2 weeks after creation and tailoring the timing to each patient. A graft is cannulated from week 2 to 4, except early-cannulation grafts [1]. On the exact timing, studies disagree:

• In Wilmink's UK study, time to first cannulation was not associated with fistula survival. Failing to achieve six successful cannulations from the start and high blood pump speeds in the first week were [5].
• In a retrospective series published in 2025 (765 fistulas), first cannulation at 1–2 weeks with a metal needle was associated with worse primary patency; with a plastic cannula there was no difference [6].

More than the exact date, what matters is the quality of the first cannulations: a vein that is ready, no failed attempts and blood flow that rises gradually.

Who cannulates

KDOQI, GEMAV and the UK recommendations agree: first cannulations are done by experienced staff with a high success rate [1,2,3]. KDOQI considers structured, supervised training reasonable before anyone does their first cannulations, and notes that simulation may be useful [3] (see a training pathway with a checklist). In practice, it helps if the same people cannulate a new fistula during its first weeks, because they know its course and its sites.

How: needle, flow and progression

These are indicative schedules from two different guidelines; your unit will have its own protocol. What they share: a small needle, low flow, slow progression and stepping back at the first incident.

The first cannulation, step by step

1. Review the map and examine the whole fistula: look, feel and listen.
2. Find the site with ultrasound: straight segment, depth, diameter and flow direction. Measure depth without pressing with the probe.
3. A gentle, brief tourniquet that steadies the vein without occluding it.
4. Asepsis per your protocol and, if you use real-time ultrasound, a sterile probe cover and gel.
5. Insert the 17G needle bevel up, at the shallowest angle that reaches the center of the vein (about 20–35°, depending on depth).
6. At flashback, lower the angle and advance only as far as needed along the center of the lumen. In a new vein, advancing too far is the easiest way to go through the back wall.
7. Flush with saline before connecting: it should go in without resistance or pain [1]. With the probe on, you will see microbubbles travel down the vein.
8. Tape the needle and lines, and keep the arm visible throughout the session.
9. At the end, withdraw the needle at the same angle and hold pressure with two fingers for at least 10 minutes. Bleeding for more than 20 minutes without excess anticoagulation may point to a stenosis [1].
10. Document the site, needle, blood flow and any incident for the next session.

Ultrasound for first cannulations

This is where it helps most. Nefrología al día considers it especially useful for first cannulations [7], and KDOQI considers it reasonable for trained staff to use it at the first cannulation of a new fistula, to see the flow direction and place the needle correctly [3]. The in-plane approach lets you see the whole needle and keep the tip under control inside a vein that is still narrow. The technique is in the guide to ultrasound-guided cannulation.

If the first cannulation fails

• Do not persist. In a new fistula, every extra attempt raises the risk of a hematoma. After two failed attempts, UK recommendations ask for another experienced colleague to needle [2].
• If it infiltrates: ice, needle removal if moderate and pressure without stopping the thrill. If dialysis is needed that day, cannulate above the injury [3]; if the patient has a catheter, the team may choose to use it. Management is in the guide to fistula infiltration.
• Tell the vascular access team if a significant hematoma forms, the thrill changes or attempts keep failing: the fistula may need more time, a Doppler scan or an intervention.
• Document it so the cause can be investigated and the plan adjusted [1].

If cannulation of a new fistula fails again and again, technique may not be the problem: a stenosis or an immature fistula are common causes of difficult cannulation (see difficult fistula cannulation).

Educational content. It does not replace supervised hands-on training or your unit's protocols.

References

1. Ibeas J, Roca-Tey R, Vallespín J, Moreno T, et al. Spanish Clinical Guidelines on Vascular Access for Haemodialysis (GEMAV). Nefrología. 2017;37(Suppl 1):1-191. doi.org
2. Vascular Access Society of Britain and Ireland (VASBI) and British Renal Society Vascular Access Special Interest Group. Clinical Practice Recommendations for Needling of Arteriovenous Fistulae and Grafts for Haemodialysis. 2018. thinkkidneys.nhs.uk
3. Lok CE, Huber TS, Lee T, Shenoy S, et al. KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update. Am J Kidney Dis. 2020;75(4 Suppl 2):S1-S164. doi.org
4. Lee T, Barker J, Allon M. Needle infiltration of arteriovenous fistulae in hemodialysis: risk factors and consequences. Am J Kidney Dis. 2006;47(6):1020-1026. doi.org
5. Wilmink T, Powers S, Hollingworth L, Stevenson T. Effect of first cannulation time and dialysis machine blood flows on survival of arteriovenous fistulas. Nephrol Dial Transplant. 2018;33(5):841-846. doi.org
6. Zhang D, Kong D, Ma L, Yang Y. Using a plastic cannula prevents arteriovenous fistula failure in early cannulation. Ren Fail. 2025;47(1):2458192. doi.org
7. Moyano Franco MJ, Salgueira Lazo M, Roca-Tey R. Punción ecoguiada del acceso vascular para hemodiálisis [Ultrasound-guided cannulation of the hemodialysis vascular access; in Spanish]. Nefrología al día. 2023. nefrologiaaldia.org