How to introduce ultrasound-guided cannulation in your dialysis unit
Buying an ultrasound machine is the easy part; the hard part is getting the team to use it with judgment and safely. This guide, written for nurse managers and educators, covers what the evidence says, what the unit needs before starting, a four-phase training pathway, a checklist for observing cannulation at the chairside and the metrics that show whether the change is working.
Key points
- It is not for every cannulation. Ultrasound pays off in the first cannulations and in difficult fistulas: deep, poorly matured, tortuous, with collaterals or with a hematoma [1,2].
- The evidence is promising but small: in difficult fistulas, fewer needle passes and more first-attempt success [4,5]. At first, cannulation is slower [4,6].
- Lack of training is the main obstacle: it is the barrier dialysis clinicians cite most often [8].
- Start with champions who train first and then teach everyone else, as one unit in Madrid did [9].
- Four-phase progression: theory and simulator, phantom, supervised patients, and sign-off with a checklist.
- Measure before and after: missed cannulations, infiltrations and new fistulas left unused because they cannot be needled.
What the evidence says
KDOQI 2019 considers ultrasound reasonable in selected patients, as long as trained staff use it: for example, at the first cannulation of a new fistula or after an infiltration. It does not recommend it for everyone because the evidence is limited, results depend on the operator and it uses resources [2]. For cannulation in general, it considers structured, supervised training reasonable before anyone does their first cannulations, and notes that simulation may be useful [2]. The Spanish reference text Nefrología al día recommends it in obese patients, with deep vessels or with fistulas that are hard to needle blind [1], and the Spanish GEMAV guideline describes it as a valuable aid in difficult native fistulas [3].
- Trials in difficult fistulas. Eves 2021: fewer additional needle passes and fewer extra skin punctures, at the cost of a slower cannulation [4]. Chen 2023, with a handheld device: first-attempt success of 96% vs 72% [5].
- There is a learning curve. In a crossover pilot with dialysis nurses, ultrasound-guided cannulation took longer than standard cannulation. The nurses gained confidence and skill with use [6], saw it as a useful adjunct and did not recommend it for every cannulation [7].
- What holds it back and what helps. In a survey of 645 clinicians from 38 countries, the most cited barrier was lack of access to ultrasound education, and the most cited facilitator was having it available [8].
- It lasts. In a unit that introduced it in 2018, nurses' views were still favorable five years later. The exception was the item on cannulation confidence, whose score fell [10].
- Simulation transfers. In central venous catheter insertion, residents trained on a simulator until they reached a minimum passing standard made fewer needle passes and fewer arterial punctures in real patients [11]. It is a different procedure and an observational study: applying it to fistulas is an extrapolation.
Before you start: what the unit needs
| Item | What you need |
|---|---|
| Ultrasound machine | A portable or handheld device with a high-frequency linear probe. Spectral Doppler is only essential for measuring access flow [1]. Keep it on the floor, charged and within reach, not in an office. |
| Asepsis | Strict aseptic technique [3]. Agree with infection control whether you will use a sterile cover and gel, as some centers do [1], and how the probe is cleaned between patients. |
| Champions | A small group of nurses who train first, answer questions on each shift and teach the rest. In one Madrid unit there were six, who then ran workshops for the rest of the staff [9]. |
| Protected time | Hours away from patient care for theory, simulator and phantom, and extra time for the first supervised cannulations, which are slower [6]. |
| Written protocol | Indications, who may cannulate with ultrasound and which training phase each person is in, and how it is documented. |
| Documentation | In the access record: segment cannulated, depth and diameter, approach and incidents. It is the basis for your metrics. |
Who to cannulate with ultrasound
Put the unit's indications in writing. The most common ones, according to Nefrología al día and KDOQI [1,2]:
- First cannulations of a new fistula (see first cannulation).
- Deep fistula or obese patient.
- Poor maturation, juxta-anastomotic stenosis, collaterals or a tortuous vein (see difficult cannulation).
- Hematoma from a previous cannulation or a recent infiltration (see infiltration).
- Repeated failed blind cannulations.
A four-phase training pathway
Each phase has a criterion for moving on. There is no consensus on the number of supervised cannulations: set it in your unit and confirm competency with the checklist, not just by counting.
| Phase | What happens | To move on |
|---|---|---|
| 1. Theory and simulator | Basic physics, machine controls, anatomy, fistula assessment and both approaches. Six 45-minute simulator sessions (next table). | Simulator score of 75 or more in the session 6 cases |
| 2. Phantom | Real needling on a gelatin or commercial model: holding probe and needle at the same time, the feel and the loss of resistance, which the simulator does not reproduce. | Tip visible throughout the advance, no back-wall puncture |
| 3. Patients, supervised | First, scanning without a needle: find the fistula, measure diameter and depth, choose the segment [9]. Then supervised cannulations of easy fistulas and, finally, of difficult ones. | Full checklist without help in the number of cannulations the unit sets |
| 4. Sign-off and upkeep | Observation with the checklist by a champion. Regular refreshers on the simulator and case reviews of difficult accesses. | Internal sign-off; yearly review or after a period without cannulating |
Phase 1: six simulator sessions
| Session | Content | Evidence of achievement |
|---|---|---|
| 1 | Orientation and ergonomics (Room and ergonomics mode) | Ergonomics score of 80 or more; probe orientation consistent with the screen |
| 2 | Machine controls and artifacts | Vessel centered, focus at its depth, five artifacts identified |
| 3 | Artery or vein and Doppler | Tell artery from vein at three sites; triphasic vs monophasic waveform |
| 4 | Maturity and fistula Doppler | Diameter within 0.5 mm; access flow within 20%; decide whether the fistula is usable |
| 5 | In-plane approach | Score of 75 or more; tip visible for at least 80% of the advance; no back-wall puncture |
| 6 | Out-of-plane approach and difficult cases | Score of 75 or more in three difficult cases |
The simulator starts at 100 points and deducts for each error: an additional skin puncture, redirections within the tissue, back-wall contact or puncture, arterial puncture, advancing without seeing the tip and moving the probe while the needle advances. The last two are typical errors of ultrasound novices [12]. The full scoring rubric is in the Fistulab teaching guide.
Chairside competency checklist
A proposal for phase 3 and sign-off. It is not a validated tool: adapt it to your unit's protocol. Mark each item "without help", "with help" or "no".
| Step | What is observed |
|---|---|
| Indication | Confirms that ultrasound-guided cannulation is indicated and reviews the access record. |
| Setup | Arm supported, operator seated, screen in line of sight and probe marker consistent with the screen. |
| Scan | Follows the vein in short axis from the anastomosis, identifies the artery (see artery vs vein), measures diameter and depth and picks a straight segment with no stenosis, aneurysm or thrombus. |
| Probe pressure | Minimal, with plenty of gel: the vein does not collapse. |
| Asepsis | Per protocol: skin prepped, sterile cover and gel if used. |
| Cannulation | Angle suited to depth, tip located before each advance, no repeated redirections, no back-wall contact or puncture. |
| Check | Flashback and saline flush with no signs of infiltration; needle aligned with the vessel inside the lumen. |
| Spacing and direction | Distance from the anastomosis and between needles per protocol; venous needle in the direction of flow. |
| Documentation | Segment, depth, approach and incidents recorded. |
How to tell whether it is working
Collect two to three months of data before you start so you have something to compare against. Useful metrics:
- Missed cannulations: percentage of sessions with more than one skin puncture per needle.
- Infiltrations per 100 sessions, with new fistulas counted separately.
- New fistulas that start being used on schedule, and catheters kept because the fistula "can't be needled".
- Cannulation time for ultrasound indications: expect it to rise at first [4,6].
- Patient experience (pain, confidence) and staff experience (a confidence survey before and after) [10].
- Actual use: ultrasound-guided cannulations per week and how many people are signed off.
Common mistakes when introducing it
- Buying the machine without a training plan. Lack of training is the main barrier [8].
- Training the whole team at once with no champions to sustain the change on every shift.
- Using it for every cannulation. It is slower and its benefits have been shown in difficult fistulas [4,6,7].
- Going straight to patients, with no simulator or phantom.
- Not documenting: without data you cannot show the benefit or justify the time spent.
- Letting the skill fade: anyone who uses ultrasound only occasionally needs refreshers.
Frequently asked questions
How many supervised cannulations does competency take?
There is no agreed number. Set a minimum in your unit and confirm competency by direct observation with a checklist, not just by counting cannulations.
Should every fistula be cannulated with ultrasound?
No. KDOQI considers it reasonable in selected patients and by trained staff [2]. It belongs in first cannulations and difficult fistulas; for an easy, mature fistula, blind cannulation remains the norm.
What ultrasound machine does the unit need?
A portable or handheld device with a high-frequency linear probe. Spectral Doppler is only essential if you also plan to measure access flow [1].
Can a simulator be used to sign off competency?
No. It prepares orientation, machine handling and coordination, and it records progress, but competency is signed off by observing real cannulations.
Should training start in plane or out of plane?
Teach both. The in-plane (long-axis) approach shows the whole needle and is the one recommended for fistulas [1]. In the out-of-plane (short-axis) approach you only see a dot and must follow the tip with dynamic needle tip positioning. Both are covered in detail in the guide to ultrasound-guided fistula cannulation.
Educational content. It does not replace supervised hands-on training or your unit's protocols.
References
- 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]. In: Lorenzo V, López Gómez JM (eds.). Nefrología al día. 2023. nefrologiaaldia.org
- Lok CE, Huber TS, Lee T, et al. KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update. Am J Kidney Dis. 2020;75(4 Suppl 2):S1–S164. doi.org
- Ibeas J, Roca-Tey R, Vallespín J, et al. Spanish Clinical Guidelines on Vascular Access for Haemodialysis (GEMAV). Nefrologia. 2017;37(Suppl 1):1–191. doi.org
- Eves J, Cai P, Latham R, et al. A randomised clinical trial of ultrasound guided cannulation of difficult fistulae for dialysis access. J Vasc Access. 2021;22(4):635–641. doi.org
- Chen S, Liu JS, Chai CC, et al. Handheld ultrasound-guided cannulation of difficult hemodialysis arteriovenous access: a randomized controlled trial. Hemodial Int. 2023;27(1):21–27. doi.org
- Schoch M, Bennett PN, Currey J, et al. Point-of-care ultrasound-guided cannulation versus standard cannulation in hemodialysis vascular access: a controlled random order crossover pilot feasibility study. J Vasc Access. 2023;24(5):1140–1149. doi.org
- Schoch M, Bennett PN, Currey J, Hutchinson AM. Nurses' perceptions of point-of-care ultrasound for haemodialysis access assessment and guided cannulation: a qualitative study. J Clin Nurs. 2023;32(23-24):8116–8125. pubmed.ncbi.nlm.nih.gov
- Schoch M, Fielding C, Marticorena RM, et al. Barriers and facilitators to vascular access point-of-care ultrasound in haemodialysis: an international survey of haemodialysis clinicians. J Ren Care. 2024. doi.org
- Molina Mejías P, Liébana Pamos B, Moreno Pérez Y, et al. Aportación de la ecografía realizada por enfermería a la exploración del acceso vascular [Contribution of nurse-performed ultrasound to vascular access assessment; in Spanish]. Enferm Nefrol. 2017;20(3):241–245. doi.org
- Grosu I, Stirbu O, Schiller A, Gadalean F, Bob F. Point-of-care arterio-venous fistula ultrasound in the outpatient hemodialysis unit: a survey on the nurses' perspective. Nurs Rep. 2024;14(1):353–361. doi.org
- Barsuk JH, McGaghie WC, Cohen ER, O'Leary KJ, Wayne DB. Simulation-based mastery learning reduces complications during central venous catheter insertion in a medical intensive care unit. Crit Care Med. 2009;37(10):2697–2701. pubmed.ncbi.nlm.nih.gov
- Sites BD, Spence BC, Gallagher JD, et al. Characterizing novice behavior associated with learning ultrasound-guided peripheral regional anesthesia. Reg Anesth Pain Med. 2007;32(2):107–115. doi.org