1. ultrasound in the dialysis unit Case studies
Dianne Du Toit

2. Benefits of ultrasound
An adjunct to standard clinical assessment
Helps to avoid infiltration by allowing staff to choose optimal cannulation sites and visualise insertion
Staff training – Visualise what you are palpating
Aid to create AVF “map” for future cannulators
Helps to identify problems- deep vessels, areas of previous infiltration, stenosis, thrombus
Images can be saved and uploaded to eMR
Staff should be provided with training

3. Depth
Perfect
Too deep

4. How deep is too deep? 30 0 24mm 1.2cm deep 900 300
If you cannulate this depth at 30 degrees you will need a minimum of 24mm length

5. Why it is so difficult to cannulate deep vessels

6. Map to guide cannulation
Patient referred from HD unit with “no access” (multiple failed arm and leg)
1 year old functioning AVF “un useable”
Septic from tunnelled femoral catheter (removed)
Vein 1cm deep and hard to palpate
No ultrasound in referring unit

7. Bruising
When there is bruising the ultrasound can be used to assess the fistula
Do the cannulation puncture sites line up with the vessel?
? Bruising may not have occurred if US used

8. Visualising our cannulation
Tells us a lot about why we are having issues

9. The “inadvertent back wall”

10. The hidden damage
Images courtesy of F. Grainer

11. Ever wonder why you can’t thread in a “perfectly good” AVF?
Images courtesy of F. Grainer

12. False aneurysm originating from AVF vein
More common than we realise post infiltration
Easily palpable
Easy to needle
Hard to thread needle
Possible outflow stenosis

13. What we see with the Ultrasound in the dialysis unit

14. The catch 22
The AVF has no stenosis and good flow but “we keep having cannulation issues” since infiltration 2 weeks ago
The “vein” is easily palpable and shallow but we keep missing
“We are getting clots in the needle”
“You need to get it fixed”

15. What the staff were palpating and cannulating

16. False aneurysm
Referred by dialysis nurses as ongoing cannulation issues
Good flow 780ml/min
Nice straight shallow vein
Multiple cannulation marks noted at widest palpable vein segment

17. Stenosis Clinical assessment – suspected stenosis
Easily seen on ultrasound
Access flow performed and 200ml/min
Recirculation 30% as both needles distal to stenosis
Referred for urgent angioplasty 17

18. How could you miss? Should be easy to cannulate
Patient area needling at home
Multiple issues with cannulation

19. When we looked….
When questioned pt had fevers for weeks at home and didn’t tell anyone
BC’s attended and +ve for Staph
Echo=bacterial endocarditis
Suspected source infected thrombus

20. Intra op
5/10/2018

21. Referred as “infected” AVF’s?
Afebrile, erythema, pain
Afebrile, erythema,
pain, stent

22. Infection
BC’s positive for staph

23. Non occlusive thrombus
Thrombophlebitis

24. Case Study – putting all the evidence together
Referral from Toowoomba hospital
Move from RBH with 3 month old BC AVF.
Swollen L side of face and neck however no headaches
Access flow > 1 litre per minute

26. Always use every tool you have
Decision not to intervene – reason?
Referred back 8 months later
Access flow 200ml/min
Non occlusive thrombus in venous cannulation zone on Ultrasound
No other info on clinical assessment given
Clue – flow was over 1000ml/min previously with known central vein occlusion (collaterals developed and supporting high flow)

27. Clinical exam tells a story
Symptoms of facial/neck swelling much improved
Collaterals not visible
AVF vein soft and non pulsatile along entire length.
No thrill at anastomosis but strong thrill 4cm proximal to anastomosis
What was going on?

28. Now, collaterals not filling as much
6 months prior, many collaterals at neck

29. What is the cause of the low flow?

30. Tight stenosis in perianastomotic region leading to poor inflow and reducing symptoms of known, long standing outflow obstruction

32. Thrombosed AVF

33. What can I do to confirm if this is clot?

34. Does it compress?

35. Is there any flow?

36. No Colour doppler, how can we tell if there is flow?

37. Flow around thrombus

39. No thrombus in proximal vein but what does the lack of colour tell us?

42. Infected buttonhole
Outside
Inside

43. What we see with our US
Aneurysm, fresh thrombus, Valve, false aneurysm
Stent with false aneurysm, Buttonhole

45. Large haematoma surrounding PTFE AVG

46. Once staff are trained and confident
Helps with staff training and promotes improved cannulation with less infiltrations
Helps to confirm clinical findings
Promotes rope ladder cannulation
Quick – especially for problematic AVF’s
Never enough in the unit to go around
No more multiple cannulation attempts

47. Conclusion
Use of a portable ultrasound by trained dialysis nurses promotes improved cannulation with pre cannulation assessment and real time visualisation to guide cannulation.
Can be used as an adjunct to clinical assessment to promote early detection of problems