Evaluation of AVF and AVG

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Meryl Burns
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1 Evaluation of AVF and AVG 2013 Nephrology Nursing Symposium Albuquerque

2 Vascular Access Leading cause of hospitalization in the ESRD population Annual cost approaching $1.5 billion (USRDS, 2004) Current Medicare expenditures for ESRD are in excess of $21 billion annually (5-7% of total Medicare expenditures, for only 1% of Medicare beneficiaries

4 Arterial Circulation

7 Examination Look Inspect entire arm helps to identify infection, swelling, bruising, thrombosis, hematoma, or aneurysms Listen Listen over fistula may identify thrombosis or stenosis Feel Palpate fistula helps recognize stenosis, thrombosis, or aneursym

8 Examination - Monitoring Access Flow Measurement Duplex Ultrasound Recirculation Study (AVF only) Static Venous Pressures (AVG)

9 Examination Why don t fistulae develop? Diseased vessel Poor location/vessel size/valves Stenosis Accessory veins Poor cardiac output

11 Baseline blood flow through brachial artery at rest 31 ml/min Blood flow through Radiocephalic AV fistula ml/min Blood flow through Brachiocephalic AV graft ml/min

13 AVF Maturation Vein diameter > 6mm Located less than 6mm below skin surface Maturation at least 6 weeks, if not progressing then refer for intervention At least 6 cm of straight fistula length Blood flow at least 600 ml/min

14 Vein hypertrophy develops with prior venous injury or stenosis Avoid venipuncture or picc lines

15 Advantages of AVF over AVG Advantages of AVG over AVF Less infection risk Lasts longer (self healing) Less blood flow Ability to cannulate through button-hole technique Can develop multiple access points Less trauma associated with creation Fewer episodes of thrombosis Can be used faster (2-3 weeks) Thrombolysis is easier and there is a longer window of success Easier to cannulate (at least during initial period) More surface area for cannulation (at least during initial use)

17 Cannulation Experienced staff does initial cannulation (K/DOQI) Take it slow, prepare patient emotionally Use topical analgesics Fistula always requires use of highly-placed (armpit) tourniquet Avoid stick within 3 cm of anastomosis Keep needles at least an inch apart Needle angle -- not too steep, not to shallow Advance needles size slowly and according to fistula strength Do not cannulate an aneurysm For AVGs, rotate sites and wait at least 2 weeks before coming within 1 cm of a prior stick

18 K/DOQI Guidelines 3.1 Cannulation skill: Staff should be appropriately trained and observed for technical mastery before cannulating any AV access. Only those with said technical mastery should be allowed to cannulate a new fistula. A protocol for minimizing vessel damage should be used for cannulation failure. Recannulation should be attempted only when the cannulation site is healed and the vessel is assessed to be normal and appropriate for cannulation. Heparin management should be reviewed on a case-by-case basis to minimize postdialysis bleeding

19 Cannulation Tips Avoid using words like stick or needling, instead use a calm voice and talk about cannulation or insertion Always explain and speak calmly while sitting with patient, avoid a rushed approach Have all the tools ready at an easy reach, avoid having to call out for assistance Acknowledge a patient s pain, never argue about their perception, it can t be hurting because it went right in without problems

20 Buttonhole Technique Dr Twardowski developed the technique in Poland over 30 years ago Dialysis supplies including needles were very limited, therefore AV fistula needles were reused for multiple cannulations The needles became dull after repeated use and would not cut the skin, but these dull needles would enter smoothly if the exact same cannulation site was used (same skin entry, same angle of entry and same vessel entry angle) Buttonhole technique was therefore developed to solve the dull needle challenge

21 Buttonhole Technique May prolong the AVF lifespan Painless (Mostly) Reduced pain, bleeding and infection. Missed sticks are virtually eliminated. Promotes self and home dialysis

22 Buttonhole Technique DON Ts of Buttonhole technique Flip the scab off with the needle you will use for cannulation this contaminates the needle Use a sterile needle this could cut the patient Let the patient pick off their scab with their fingers Stick through the scab DO s of Buttonhole technique Aseptic tweezers Soak 2X2 with NS or alcohol-based get Place a warm, moist washcloth over sites Stretch skin around scab in opposite directions Have patient tape alcohol squares over sites prior to dialysis

23 Flow Rates 17 Gauge 300 ml/min or less 16 Gauge ml/min 15 Gauge ml/min 14 Gauge >450 ml/min

27 Complications Aneurysms Pseudoaneurysms Stenosis Thrombosis Hematoma/Infiltrations/Spontaneous hemorrhage Vascular steal (distal insufficiency) Infection Excessive growth Pulmonary hypertension

Infiltration What to do if it occurs Rest the fistula Ice for the first 24 hours Warm compress after the first 24 hours Patient instructions must be clear with a

28 Infiltration What to do if it occurs Rest the fistula Ice for the first 24 hours Warm compress after the first 24 hours Patient instructions must be clear with a take-home instruction sheet and documentation of the event. For future cannulation, consider using wet needle approach and confirm good flows with saline before blood

33 pseudoaneurysm

34 pseudoaneurysm

37 Elevated Venous Pressure Venous stenosis Poor needle position Early thrombosis of lines Wrong direction of blood flow

38 Arterial Pressure Increasingly negative pre pump AP indicates insufficient blood inflow to meet the blood pump BFR demand Larger-gauge needles may be needed for higher BFR settings Check to make sure that needle is not obstructed or that blood line is not kinked Blood pump speed as prescribed may not be attainable and may need to be reduced if/until cause is identified and remedied Notify physician that access flow is not sufficient If pre pump negative pressure is extreme ( 300 mm Hg) or rises rapidly during dialysis, act quickly; reduce blood pump speed until pressure falls into acceptable range, check blood lines for kink, and notify physician

39 Signs of Stenosis Clotting the system 2 or more times/month Difficult needle placement Persistently swollen arm Increased machine pressures Difficult achieving hemostasis at the end of treatment Decreased blood pump speeds Decreased Kt/V or URR (due to recirculation)

40 Quiz 1. What are the three senses involved in AVF or AVG assessment? a) Look, Feel, and Listen b) Look, Smell, and Touch c) Breathe, Observe, and Speak d) Speak, Touch, and Witness

41 Quiz 2. If the cannulation site begins to bleed 15 minutes after adequate compression, things to consider include: a. Venous Outflow Stenosis b. Excessive heparin use c. Patient taking Plavix d. All of the above

42 Quiz 3. AV fistulae are superior to AV graft for all of the following reasons except: a) Less infections b) Ability to use earlier c) Lasts longer d) Lower blood flows usually seen

43 Quiz 1. Signs of a central vein stenosis include: 1. Swollen feet 2. High arterial pressures 3. Swollen access arm 4. Numerous collateral veins over chest wall

44 Quiz 1. The following are associated with the buttonhole technique: 1. Allows for patients to self cannulate earlier 2. Evolved as a technique to reuse old dialyzers 3. Patients must remove scabs with sterile fingernails 4. It is best to push the needle in as far as it can go to prevent leaks 5. Leads to aneurysm development

The Buttonhole Technique for AV Fistula Cannulation

The Buttonhole Technique for AV Fistula Cannulation Lynda K. Ball, RN, MSN, CNN October 16 & 17, 2008 Trends in Nephrology Nursing Kaiser Permanente Acute Dialysis Symposium 1 CMS Disclaimer This publication