# N7 — AVF/AVG Assessment and Cannulation

N7 — AVF/AVG Assessment and Cannulation FRONT Front · at the chair

**When:** before every cannulation, and at needle removal.

### Do this

1.  **Wash and look.** The patient washes the access arm before cannulation. Look for redness, swelling, drainage, skin breakdown, thin or shiny skin over an aneurysm, a cool or discolored hand, and neck or chest collaterals \[[5](https://urinenephrology.org/mastery/maintenance-hd/nursing/N7-AVF-AVG-Assessment-and-Cannulation.html#n7-ref-5)\].
2.  **Listen.** Normal: low-pitched, continuous bruit. Abnormal: high-pitched, systolic-only, or absent.
3.  **Feel.** Normal: soft, compressible vessel with a thrill. Abnormal: hard pulsatile segment, weak thrill, “mushy” graft, or no thrill.
4.  **Test.** Raise the arm — a fistula should collapse. Occlude above the anastomosis — the pulse should augment.
5.  **Confirm flow direction** before placing needles; use ultrasound for a new or difficult access if trained.
6.  **Rope ladder:** rotate both sites along the full length of the access. No area puncture \[[5](https://urinenephrology.org/mastery/maintenance-hd/nursing/N7-AVF-AVG-Assessment-and-Cannulation.html#n7-ref-5)\].
7.  **Needles:** gauge matched to the prescribed blood flow per your unit protocol. Venous needle always antegrade; avoid a retrograde, bevel-down arterial needle \[[6](https://urinenephrology.org/mastery/maintenance-hd/nursing/N7-AVF-AVG-Assessment-and-Cannulation.html#n7-ref-6)\].
8.  **First cannulations of a new fistula** go to the most skilled cannulator.
9.  **After dialysis:** firm pressure on the puncture site — enough to stop bleeding, not enough to lose the thrill.

### Call the nephrologist when

- **Same day:** no thrill **and** no bruit; a rapidly expanding hematoma; a cold, pale, painful, or weak hand; bleeding you cannot control; thin, shiny, ulcerated, or scabbed skin over an aneurysm.
- **Prompt assessment:** pus, spreading redness, or fever — notify the clinician now; fever with rigors, hypotension, confusion, or other systemic illness needs immediate assessment. Obtain ordered cultures before antibiotics when this will not delay urgent treatment.
- **At rounds:** new difficulty cannulating, clots aspirated, prescribed blood flow not reached, needle sites bleeding longer than usual for 3 sessions in a row, an unexplained Kt/V drop of more than 0.2, or arm, face, or breast swelling \[[5](https://urinenephrology.org/mastery/maintenance-hd/nursing/N7-AVF-AVG-Assessment-and-Cannulation.html#n7-ref-5)\].

Urgency note: [Surviving Sepsis Campaign guidance](https://pmc.ncbi.nlm.nih.gov/articles/PMC8486643/) supports prompt treatment; collecting cultures must not substantially delay antibiotics in suspected sepsis.

### Don’t

- Don’t cannulate a fistula within 14 days of creation \[[3](https://urinenephrology.org/mastery/maintenance-hd/nursing/N7-AVF-AVG-Assessment-and-Cannulation.html#n7-ref-3)\], or before the access team has cleared it.
- Don’t buttonhole a graft — ever. Don’t start a buttonhole without an order and an indication \[[2](https://urinenephrology.org/mastery/maintenance-hd/nursing/N7-AVF-AVG-Assessment-and-Cannulation.html#n7-ref-2)\].
- Don’t needle the top of an aneurysm.
- Don’t allow BP cuffs, IVs, or blood draws on the access arm (per your unit protocol); flag any PICC request to the nephrologist.
- Don’t press on the vessel downstream of a bleeding point.

N7 — AVF/AVG Assessment and Cannulation BACK Back · why, and the evidence

### Why

1.  Physical exam by trained staff agreed with angiography in about 89% of outflow and 80% of inflow stenoses \[[1](https://urinenephrology.org/mastery/maintenance-hd/nursing/N7-AVF-AVG-Assessment-and-Cannulation.html#n7-ref-1)\].
2.  Buttonhole cannulation carried 2.6 times the access-related bloodstream infection risk of rope ladder in national CDC data \[[2](https://urinenephrology.org/mastery/maintenance-hd/nursing/N7-AVF-AVG-Assessment-and-Cannulation.html#n7-ref-2)\]; *S. aureus* bacteremia was 13% versus 0% at 1 year in a randomized trial \[[7](https://urinenephrology.org/mastery/maintenance-hd/nursing/N7-AVF-AVG-Assessment-and-Cannulation.html#n7-ref-7)\].
3.  Cannulating a fistula within 14 days of creation was associated with 2.1-fold higher risk of fistula failure \[[3](https://urinenephrology.org/mastery/maintenance-hd/nursing/N7-AVF-AVG-Assessment-and-Cannulation.html#n7-ref-3)\].
4.  A major infiltration added a median of 97 days on a catheter, and 26% of infiltrated fistulas clotted \[[4](https://urinenephrology.org/mastery/maintenance-hd/nursing/N7-AVF-AVG-Assessment-and-Cannulation.html#n7-ref-4)\].
5.  KDOQI 2019: examine the access before every cannulation; surveillance numbers are supplementary — act on clinical findings \[[5](https://urinenephrology.org/mastery/maintenance-hd/nursing/N7-AVF-AVG-Assessment-and-Cannulation.html#n7-ref-5)\].

### Go deeper

- Mastery page: [Examining and Cannulating the AVF and AVG](https://urinenephrology.org/mastery/maintenance-hd/avf-avg-exam-cannulation.html)
- [All dialysis nursing reference cards](https://urinenephrology.org/mastery/maintenance-hd/nursing/index.html)

### References

1.  Asif A, et al. Accuracy of physical examination in the detection of arteriovenous fistula stenosis. *Clin J Am Soc Nephrol.* 2007;2:1191-1194. [PubMed 17928468](https://pubmed.ncbi.nlm.nih.gov/17928468/)
2.  Lyman M, et al. Risk of vascular access infection associated with buttonhole cannulation of fistulas (NHSN). *Am J Kidney Dis.* 2020;76:82-89. [PubMed 32151430](https://pubmed.ncbi.nlm.nih.gov/32151430/)
3.  Rayner HC, et al. Creation, cannulation and survival of arteriovenous fistulae: data from DOPPS. *Kidney Int.* 2003;63:323-330. [PubMed 12472799](https://pubmed.ncbi.nlm.nih.gov/12472799/)
4.  Lee T, Barker J, Allon M. Needle infiltration of arteriovenous fistulae in hemodialysis: risk factors and consequences. *Am J Kidney Dis.* 2006;47:1020-1026. [PubMed 16731297](https://pubmed.ncbi.nlm.nih.gov/16731297/)
5.  Lok CE, et al. KDOQI clinical practice guideline for vascular access: 2019 update. *Am J Kidney Dis.* 2020;75(4 Suppl 2):S1-S164. [PubMed 32778223](https://pubmed.ncbi.nlm.nih.gov/32778223/)
6.  Parisotto MT, et al. Cannulation technique influences arteriovenous fistula and graft survival. *Kidney Int.* 2014;86:790-797. [PubMed 24717298](https://pubmed.ncbi.nlm.nih.gov/24717298/)
7.  MacRae JM, et al. Arteriovenous fistula survival and needling technique: long-term results from a randomized buttonhole trial. *Am J Kidney Dis.* 2014;63:636-642. [PubMed 24239019](https://pubmed.ncbi.nlm.nih.gov/24239019/)

Reviewed by Andrew Bland, MD, FACP, FAAP · v1.0 draft 2026-09-26. For education; the physician’s written order and the unit protocol always govern.


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[Website version](https://urinenephrology.org/mastery/maintenance-hd/nursing/N7-AVF-AVG-Assessment-and-Cannulation.html) · Markdown synchronized October 3, 2026.