Fistula infiltration in dialysis: prevention and management
An infiltration (extravasation) happens when blood or saline leaks out of the fistula vein into the surrounding tissue and forms a hematoma. This guide for hemodialysis nurses, technicians and physicians explains why dialysis needles infiltrate, how to prevent it and what to do step by step if a fistula infiltrates.
Key points
- In a 5-year series, major infiltration (severe enough to prolong catheter use) occurred at an annual rate of 5.2%. It was more likely in fistulas less than 6 months old and in older patients [3].
- The consequences are serious: thrombosis in 26% of cases and a median of 97 extra days on a catheter [3].
- Prevention: always know where the tip is (ultrasound helps), flush with saline before connecting, flatten the needle after flashback, don't flip it, and tape needles and lines securely [1,2].
- If it happens: ice for at least 10 minutes and don't push the blood pump to its maximum; if moderate, remove the needle and hold pressure; if dialysis is needed, cannulate proximal to the injury [1].
- Check the thrill and hand circulation, document the event and notify the vascular access team if the access is at risk.
What is fistula infiltration?
Infiltration means the needle tip is not fully inside the lumen of the arterialized vein, or the hole in the vein wall bleeds outward. Blood (or flush saline) collects in the tissue around the vein, causing swelling, pain and, over time, a hematoma. The Spanish GEMAV guideline lists infiltration-hematoma among the typical complications of poor cannulation technique [2]. In a prospective study of 1,946 cannulations, 4.4% were missed cannulations and one third of patients had at least one; extravasation was recorded in 0.9% [4].
The most common mechanisms are:
- Back-wall puncture (transfixion): the needle goes through the far wall. A steep angle and an overly long needle make it more likely: use the shortest needle that reaches the center of the lumen [2].
- Tip against the vessel wall, or the bevel partly outside the lumen. A steep angle, high blood flow rates and a deep needle tip increase stress on the back wall [5].
- Needle flipping (180° rotation): widens the hole, can injure the endothelium and cause infiltration through the side wall during treatment. It is no longer recommended [2].
- Needle movement or dislodgement during treatment, from poor taping or arm movement [2].
- Poor hemostasis after needle removal: if the inner hole in the vein wall is not compressed, blood leaks into the subcutaneous tissue [2].
| When | Typical mechanism | What you notice |
|---|---|---|
| At cannulation, before connecting | Back-wall puncture, tip in the wall, repeated attempts | Immediate swelling and pain; saline doesn't flush smoothly or flashback is lost |
| During treatment | Needle moved, flipped or poorly taped; high pump speed with a misplaced tip | Progressive swelling, pain or burning around the needle; poor blood flow |
| At needle removal | Pressure that doesn't cover the inner hole | Hematoma after treatment or in the following hours |
Risk factors
- New fistula. In the Lee study, 43.5% of major infiltrations occurred in fistulas less than 6 months old, versus 20.5% of controls (OR 2.98). Risk also rose with age [3].
- Difficult fistula: a deep, underdeveloped or tortuous vein, or one with hematomas from previous attempts. These are the situations where Spanish nephrology literature recommends ultrasound-guided cannulation [6].
- Technique: on top of the mechanisms above, repeated attempts by the same cannulator, a practice GEMAV considers unacceptable [2].
- Tourniquet: it should stabilize the vein, not occlude it [2]. Use it to cannulate and remove it before treatment starts.
- Needle gauge not matched to blood flow. For first cannulations, use a 17G needle (blood flow around 200 mL/min): if extravasation occurs, the hematoma is smaller. Keep pre-pump arterial pressure no lower than −250 mmHg [2].
- Poor taping of needles or lines, especially when lines are secured to moving objects such as the chair or a pillow [2].
How to prevent infiltration
1. Plan with ultrasound
Before cannulating, measure the diameter and depth, find a straight segment and rule out hematomas or stenosis at the chosen site. KDOQI 2019 considers it reasonable for trained operators to use ultrasound to determine flow direction and proper needle placement, to prevent cannulation complications [1]. In a randomized trial in difficult fistulas, ultrasound guidance reduced additional needle passes (72 vs 99) and additional skin punctures (10 vs 25), although complications did not differ [7].
2. Control the angle and the tip
For an AVF, enter at about 25° (20–35° depending on depth) with the bevel up. Once you get flashback, flatten the needle and advance along the center of the lumen [2]. With the long-axis (in-plane) approach you see the whole needle, tip included, along its entire path [6]. Do not flip the needle.
3. Do a saline flush test before connecting
For first and difficult cannulations, GEMAV advises confirming needle position with a saline-filled syringe, to avoid blood extravasation [2]. With the tip in the lumen, saline flows in with no resistance and no pain. On ultrasound, you see a plume of microbubbles traveling downstream along the vein. With the tip outside, saline pools around the vessel as an anechoic halo: stop flushing and reposition the needle.
4. Secure needles and lines
Tape needles securely to the skin and keep them visible throughout treatment. Secure the lines to the access arm itself, with enough slack to prevent pulling. Keep the access limb in view [2].
How to recognize an infiltration
- Swelling or firmness around the needle, which can grow quickly.
- New pain, burning or tightness reported by the patient.
- Skin discoloration or bruising.
- Difficulty drawing or returning blood; saline doesn't flush smoothly.
- On ultrasound, a hypo- or anechoic collection around the vein with no color Doppler flow [8].
Don't wait for an alarm: even venous needle dislodgement isn't always detected. In one study, only 29% of fistulas had an intra-access pressure high enough for venous pressure monitoring to detect it [9]. Check the access arm often.
What to do if a fistula infiltrates
Always follow your unit's protocol. These are the interventions KDOQI 2019 considers reasonable (expert opinion) [1]:
- Infiltration of any size: apply ice for at least 10 minutes and don't push the blood pump speed to its maximum.
- Moderate infiltration: remove the needle (stop the pump and clamp the line per your protocol) and hold manual pressure over the infiltration site. Pressure should be firm without stopping flow through the fistula: you should still feel the thrill [1,2].
- Large infiltration: in addition, decide whether the patient needs dialysis that day. If so, cannulate a site proximal to the injury, closer to the heart. If that's not possible, don't reattempt in the injured area until manual pressure and ice have been applied for 30 minutes.
- If a hematoma develops: assess the site, the access and the arm. Measure the swelling, check flow in the access above and below the hematoma, and check circulation to the hand.
- Document the event and report it. GEMAV asks units to record every cannulation incident so it can be reviewed and corrected [2].
Contact the nephrologist or vascular access team if the thrill or bruit is absent, the hematoma is large or still growing, the hand is cold, pale or painful, the access can't be used, or infiltrations keep happening. They decide whether to rest the fistula, order a Doppler ultrasound or intervene.
Consequences of infiltration
| Consequence | Why it matters |
|---|---|
| Hematoma | Makes later cannulation harder, reduces available sites and can compress the vein [2] |
| Thrombosis | Occurred in 26% of major infiltrations [3]; external pressure or a later stenosis can cause it [2] |
| More catheter days and procedures | Median of 97 extra days on a catheter and 2.4 tests or interventions per episode [3] |
| Missed or shortened treatments | Extra needle sticks, inadequate dialysis, discomfort and fear of cannulation [2] |
| Loss of the access | Cannulation complications can force catheter use while a new fistula is created and matures [2] |
Frequently asked questions
What do you do if a fistula infiltrates during dialysis?
Apply ice for at least 10 minutes and don't push the blood pump to its maximum. If the infiltration is moderate, remove the needle and hold pressure without stopping the thrill. If it's large, decide with the team whether dialysis is needed that day and, if so, cannulate proximal to the injury [1]. Check the thrill and hand circulation, and document the event.
Can you cannulate an infiltrated fistula again?
If dialysis is needed that day, KDOQI suggests cannulating proximal to the injury. If that's not possible, reattempt in the area only after 30 minutes of pressure and ice [1]. At later sessions, avoid the hematoma and choose a healthy segment with ultrasound. After a large infiltration, the decision belongs to the vascular access team.
Ice or heat for a fistula infiltration?
In the acute phase, ice: KDOQI recommends ice for at least 10 minutes for any infiltration [1]. The guidelines cited here make no recommendation on heat in the following days, so follow your unit's protocol.
Is an AV fistula infiltration serious?
It can be. In the Lee study, one in four major infiltrations led to thrombosis, and patients needed a catheter for a median of 97 extra days [3]. That's why you act quickly and keep checking the thrill afterward.
Does ultrasound-guided cannulation prevent infiltration?
It helps you locate the tip and reduces needle passes and skin punctures in difficult fistulas [7], and KDOQI considers it reasonable to prevent complications [1]. However, that trial did not show fewer complications: ultrasound does not replace good technique.
Educational content. It does not replace supervised hands-on training or your unit's protocols.
References
- Lok CE, Huber TS, Lee T, et al. KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update (statements 12.1 and 12.2, AV access cannulation complications). 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), section 3.3: use of the AVF. Nefrología. 2017;37(Suppl 1):1–191. doi.org
- 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
- Coventry LL, Hosking JM, Chan DT, et al. Variables associated with successful vascular access cannulation in hemodialysis patients: a prospective cohort study. BMC Nephrol. 2019;20(1):197. doi.org
- Kumbar L, Ramani K, Brouwer-Maier D. Considerations in access cannulation: traditional and evolving approaches. Adv Chronic Kidney Dis. 2020;27(3):199–207. doi.org
- Moyano Franco MJ, Salgueira Lazo M, Roca-Tey R. Punción ecoguiada del acceso vascular para hemodiálisis [Ultrasound-guided cannulation of the hemodialysis vascular access]. Nefrología al día (in Spanish). nefrologiaaldia.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. doi.org
- Sharbidre KG, Alexander LF, Varma RK, et al. Hemodialysis access: US for preprocedural mapping and evaluation of maturity and access dysfunction. RadioGraphics. 2024;44(1):e230053. doi.org
- Ribitsch W, Schilcher G, Hafner-Giessauf H, et al. Prevalence of detectable venous pressure drops expected with venous needle dislodgement. Semin Dial. 2014;27(5):507–511. doi.org