1

Subcutaneous anastomosis (communications)

of an artery to a vein, allowing blood flow

directly moves from artery to vein

Arteriovenous fistula (AVF)

2

3

AVF is a continuous circuit (not only anastomosis)

Starts at the heart and ends at the heart

The circuit:

Usually the anastomosis is made at the wrist

between the radial artery and the cephalic vein4

Advantages of AVFLower risk of infection

Lower tendency to clot fewer 2ry interventions

Lower hospitalization rates (lower complication

rates ,lower morbidity and mortality)

Allows for greater blood flow

Long-term patency (improved performance with

time)

Less cost of implantation and maintenance.5

Disadvantages of AVF1. Slow maturation and failure of maturation

2. More difficult to needle.

3. Increase in size with age and aneurysm

formation.

4. Cosmetic appearance of dilated veins.

6

Vascular anatomy of upper limb

• Basilic vein: drain medial side of upper limb

• Cephalic vein: drain lateral side of upper limb7

Types of common arteriovenous fistula according to method of anastomosis:

8

Types of common arteriovenous fistula according to its site in the upper limb

Forearm

AVF

Radial artery to cephalic vein

Radial artery to basilic vein

Radial artery to any other transposition

Arm AVF Brachial artery to cephalic vein

Brachial artery to basilic vein

Brachial artery to any other

transposition9

1.Radial–cephalic AV fistula ( wrist )

10

2.Brachial–cephalic AV fistula (elbow)

11

3.A transposed brachial basilic vein fistula

12

13

•Pre-operative care in hand for AVFThis begins as soon as finish vascular assessment

and site for access was decided.

Don’t insert peripheral IV catheters or cardiac

pacemaker

Don’t use for blood draws or IV drugs

Don’t use for taking blood pressure or try any

surgical procedures

Surgeon may ask for duplex ultrasound.14

Post-Operative care of AVF or AVGsImmediately following surgery (half-hourly at first),

the site of AVF should be checked for :

Excessive bleeding, haematoma, swelling, pain and

later signs of infection such as raised temperature.

Check radial pulse, colour, movement, warmth, and

sensitivity of affected limb to ensure blood flow

reaches extremities (peripheral circulation).15

Assess the access patency: palpate (thrill) or listen

(bruit)

Monitor BP and hydration status, to prevent access

clotting.

Elevate the access arm to help minimize oedema

and swelling.

Assess patient for pain

Report any abnormality to medical team ASAP.16

Patient Education (Daily Care)Good fistula care will help maintain the patency of

the vascular access.

Education is the responsibility of the nurse:

•Check the thrill at least once daily

•Avoid tight clothing , jewellery or watch

•Avoid carrying heavy object

•Avoid exposure to extremes of heat/cold 17

Avoid check BP, venipuncture or IV drugs ,

sleeping on the access arm

Use the access site only for dialysis

Wash the access with soap and water pre-dialysis

Signs of infection (pain, swelling, redness…….)

Absence of thrill must be reported to the renal unit.

(The fistula may need 6–8 weeks to mature and

ideally ≥12 weeks. )18

19

Cannulation is one of the 1ry causes of AVF failure

Sequences of needle punctures into the vessel wall

Endothelial injury leukocyte adhesion migration

of smooth muscle cells from the media to the intima

and proliferation.

Intimal hyperplasia thickening of the vessel wall

venous stenosis (main cause of access failure).

Infiltration, aneurysms and hematoma needle-

induced vessel injury 20

Personal protective devices

(Standard Precautions)Strict hand washing

Eye protection (face shield or goggles)

Mask

Gloves

(Use according to unit standards to ensure staff

protection) 21

Rapid examination AVF

• LOOK

• FEEL

• LITEN

22

Fistula maturation

Rule of 6's

6 weeks old

6 mm deep

6 mm fistula diameter

600mL per min flow 23

Skin PreparationPatients should wash their hands with anti-bacterial

soap and water before dialysis scission

Clean the skin using 2% Chlorhexidine gluconate

solution with alcohol (drying time 30 seconds),

Povidine-iodine (drying time 2–3 min), using friction

and a circular motion

Leave the solution to dry, prior to needle insertion

Do not touch skin after cleaning (If touch, re-clean)24

25

Local Anesthetic

Use of topical anaesthesia (lidocaine

cream) on site of cannulation at least

half an hour prior to cannulation.

26

Needle types

Two main types

1.Metal needle 2.Plastic needle

27

Metal needle28

Plastic needle 29

General rules for cannulation The initial cannulation will be a sharp metal needle

(metal needles are either sharp or blunt bevel).

To begin rope ladder/rotating site technique

Same-site cannulation in order to establish tunnel tracks

for the buttonhole technique.

Plastic cannulas can be left in the vessel for a period of

time to develop the buttonhole tunnel track.30

Sharp needles, used for the rope ladder

technique, have a sharp cutting edge.

Blunt needles, designed for the buttonhole

technique, are rounded on top (no sharp edge)

Black and red dots indicate the position of the

needle even during the treatment ( to know if

flipping happen after insertion of needle ).

Wing colour indicates needle diameter 31

Needle length1. Metal needles are range from 2.5cm to1.5cm

(which is for shallow new fistula).

2. Plastic cannula needles can be up to 3.8 cm (which

is for deep AVF)

32

Metal needle Plastic needle

• Cannulation is easy

• Miscannulations is low

• Low cost

• Severe vessel injury

• Higher risk of needle infiltration

during taping or mid-treatment

• Limited areas for Cannulation

• Less comfortable for patients’ arm

movements during the dialysis

• Not suitable for deep AVF cannulation

. Difficult

. High

. Higher

. Less

. Low

. Increased

. Comfortable

. Suitable 33

Needle site selection (Placement of needles)

4-5 cm (1.5-2 inches) apart, hub to hub, if

needles in the same direction

2.5 cm (1 inch) apart, hub to hub ,if needles

in opposite direction

Insertion site or needle tip once inserted, 4

cm (1.5 inches) away from the anastomosis

34

35

Venous needle pointing in the direction of the

blood flow

Arterial needle pointing toward the arterial

anastomosis.

Venous needle must point toward the venous

return and arterial needle, may point in any

direction.

May use ultrasound mapping for depth and size.36

37

38

Needle size selection 17 gauge needle for first attempts and for one

week with two needle cannulation without

complication

Increase needle gauge till 15 gauge needles

39

During choice the needle size , Must follow the

2:1 rule- arterial and venous pressure should not

exceed 50% of the pump speed e.g., 400 ml/min

blood pump speed, arterial and venous pressure

should be -200/200 mm/hg respectively

Arterial and venous pressure should not exceed -

250 or 250 mm/hg to avoid damage to the access

40

Back eyeThe arterial needle should always have a back-eye

It should be smooth and flat so that its rim does not

cut into the vessel during needle insertion or

withdrawal.

Maximize flow from the access.

Prevents suction of the needle to the inner vessel

wall and reduces the need for rotating the needle,

which adds trauma to the AVF.41

42

Bevel position/ flipping of needleAngle of insertion is 20-35 degree (depending on

vein depth)

The retrograde direction of the arterial needle and

bevel down cannulation increase possibility of

access failure

The antegrade direction of the arterial needle with

bevel up cannulation may improve access survival 43

Avoid flipping (rotating)the needle as this will

cause coring of the vessel

If flipping is essential as in case of increased

needle pressures, must be done carefully to avoid

damage to access (if fistula needles with a back-

eye the need to flipping the needle is decreased)44

Better use the ultrasound to determine optimal

cannulation sites and assess needle position,

before re-positioning the fistula needle

45

Number of attempts Better to use the portable ultrasound if available

for assessment of needle position and vein

depth/diameter

If cannulation is failed or infiltration occurs, call

cannulator or clinical educator

Don’t push saline or blood ,if unable to aspirate

blood from needle46

If doubt that needle has infiltrated, remove the

needle to decrease vessel damage and apply ice

If patient has received heparin, leave the needle in

place , apply ice and give protamine sulfate

Consider resting the access until infiltration and

bruising has improved. (Follow unit policies)

The additional attempt must be done by an expert

cannulator , if the dialysis is life saving and better

use single needle dialysis (when available) 47

Securing of needles Needles should be secured at the same angle of

insertion to avoid change in needle position and

minimize risk of infiltration

It also should be secured during treatment to avoid

accidental malposition or dislodgment of needles

Access limb and connections should be visible at

all times and should not be covered with blankets.

(Follow unit policies). 48

Needle Removal and HemostasisNeedles should be removed at the same angle of

insertion

Do not apply pressure while the needle is in the

vein

Once the needle is completely removed, use a 2-

digit technique (one finger at the skin level and one

at the vein level) for maximum hemostasis49

Dispose of the needle ( follow Occupational Health

standards)

Make press at least for 10 min without releasing

pressure (during applying pressure, ensure a thrill

can be felt in the access)

If thrill cannot be felt, remove hand slowly and

assess the thrill

50

Troubleshooting Needle Placement and

increased venous and/ or arterial pressures. Decrease blood pump speed

Measure blood pressure and review previous clinical

records to determine baseline blood pressure, venous

and arterial pressures and blood flow rate

Assess thrill and bruit and observe for infiltration

(swelling)51

Carefully reposition access limb

Use portable ultrasound to check position of

needle prior to re-positioning or adjusting needle

(if available)

Carefully adjust tape or place a small gauze under

the needle wings (as needed), while closely

monitoring venous and arterial pressures

If successful, secure needle in position with tape

while monitoring venous and arterial pressures. 52

If unsuccessful, recirculate patient’s blood and

recheck needle position with portable ultrasound If

repositioning is unsuccessful, remove fistula needle

Before re-cannulation, ask help the clinical educator

nurse

Repeat clinical assessment of AV access (thrill, bruit

and portable ultrasound) prior to repeating

cannulation.

Better to avoid repeated cannulation

(Follow unit policies).53

Complications of Cannulation of Needle

2.During HD

1.During cannulation 3.On needle removal

54

During cannulation (extravasation)Needling an AVF which is too small, not mature

enough, or very mobile can easily lead to

extravasation, the needle may be inadvertently pierces

through the side or back wall of the fistula.

Signs and symptoms of extravasation include:

1.Pain

2.Swelling

3.Bruising.

55

Extravasation is treated by applying pressure, ice, and

administering analgesia.

Blown arterial needle with satisfactory flow can be

used but extravasated venous needle should not be used

for HD and use alternative access till the swelling

subsides.

If extravasation is a usual problem, the patients should

only be needled by experienced nurses with use of

small-bore needles and referral for a surgical opinion.56

57

Problems during HDNeedle dislodgement

Can be identified by pressure alarms on the

machine, bleeding from needle entry site,

excessive pain, swelling and bruising

May be resolved by adjusting the needle or

by removing the needle and re-cannulation

58

Suckling up of needle against the

vessels wall

Reduced arterial pressure and mild

pain or vibration at the arterial needle

site

The needle will need to be rotated to

achieve a good flow.

59

Needles fall out during HD

Result from poorly secured needle sites

or excessive patient movement.

Pressure on needle hole, stop HD and the

extracorporeal re-circulated.

Once haemostasis is achieved the patient

may be re- cannulation and start HD.

60

Problems following dialysis ( on needle removal)

Delayed haemostasisMost common complication following HD

Not turning off the heparin infusion soon enough

Using too much heparin

Inadequate pressure being applied on site of cannulation

Pressure being taken off too soon following needle removal.

If over-heparinization is suspected protamine may be

administered.

61

Cannulation Techniques

Site-Rotation Buttonhole

Known as:1 .Rope ladder

2 .Rotating sites

Known as:1 .Constant-site

2 .Same-site

62

Rope ladder ( Site- Rotation technique):

Cannulation sites are rotated up and down the

AVF to use its entire length with equal

distribution of the puncture sites

This is the classic technique used in most

dialysis centers

Cannulation in straight line at least 1–2cm for

each cannulation site

63

No need to ‘straighten out’ by pulling on the

vessel to cannulates, the vessel will retract

into its original position when released and

lead to an infiltration

Each treatment requires 2 new sites

Disadvantage:

Small dilatations over the whole fistula.

Concerns of ‘ one-site-itis’

64

Advantage:

lower rate of infection

Help expand the lifespan of the fistula.

Changing cannulation site gives the previous

needle site time to heal and decrease the chance

of formation of aneurysms.

It is thought rope ladder needling reduces the

risk of stenosis.

65

66

67

68

“ONE-SITE–ITIS”

Occurs when cannulates the needle in the same

general area, session after session

Causes aneurysm and stenosis formation

69

Buttonhole TechniqueMethod in which an individual cannulates the AV

fistula in the exact same spot, at the same angle and

depth of penetration every time

After about 10 cannulations using sharp dialysis

needles, the buttonhole site will develop a scar tunnel

track.

This track is the same as a pierced ear that has scar

tissue formed and will cause less to no pain or bleeding

when cannulated.

70

After the buttonhole is created, a blunt dialysis needle

should be used, which eliminates the risks of cuts and

bleeding to the tract.

71

ADVANTAGES

May prolong AVF lifespan

Reduce needling attempts

Reduces pain

Reduces bleeding and hematoma

Reduces infiltration

Reduces aneurysms

Promotes self-care and self-dialysis

Use blunt needles, which require no safety device

72

DISADVANTAGES

Requires same cannulator, same angle, same

location

High rate of infection

Concerns of ‘one-site-its’

Difficult with fistula covered by:

1.Heavily scarred skin

2.Large amount of subcutaneous tissue

73

Indications of buttonhole technique:

Indication to use rope ladder technique

• AVF is short in length or has short usable segments

• AVF is relatively straight

• AVF with tortuous anatomy

• Patient has hand tremors.

• AVF with aneurysmal dilatation

• Poor vision or placement of needle on the BH lead to the creation of multiple tracts within the BH

74

Indications of buttonhole technique:

Indication to use rope ladder technique

• AVF is difficult to cannulates (self cannulation)

• Patient reports or demonstrates difficulty visualizing the BH site.

• AVF is mature • Multiple tracts within the BH

• Patient preference.• Needle phobia

75

Complications of fistula

76

1-Aneurysm , Pseudo aneurysmA consequence of an AV fistula creation is

thickening and enlargement of the vein walls due to

arterialization.

Over time, flow in the fistula increases and the

vein enlarges and may become tortuous.

An aneurysm is a weak spot in the wall of the

fistula which causes ballooning of the vessel wall.

77

This aneurysm is secondary to repetitive

cannulation in the same area (same=site itis)

which lead to weakness of vessels walls

Pseudo aneurysm collection of blood in the tissue

surrounding a vascular access can occur if

improper control of bleeding after the dialysis

needles is removed (pulsating extravascular

hematomas).

78

Aneurysm and pseudo aneurysm may also be

caused by a proximal stenosis.

Patients with aneurysms may present to the

emergency department reporting extremity pain,

neurologic dysfunction secondary to aneurysmal

impingement of surrounding nerves, significant

thinning of overlying fistula skin, or hemorrhage

secondary to this skin erosion

79

Diagnosis Both AV fistula aneurysm and pseudoaneurysms

can be identified with the use of Doppler US.

80

Management: Changing needle sites and vascular surgery

for operative repair.

Surgery is indicated when the aneurysmal

dilatation is >2cm, pulsatile pain is present in

the aneurysm, and the overlying skin appears

glossy and discoloured (risk of rupture,

perforation and ulceration)

81

2-Infection:AV fistulas have lowest risk of infection of any

vascular access type.

Pre- cannulation must checking signs of infection

over skin of AVF

1.Redness or raise temperature on exit site of fistula

2.Swelling or hardness.

3.Purulent discharge from needle sites.

4.Tenderness or pain.

82

Causes

Inadequate disinfection of the skin

Contamination of the needle

Manipulation of the needle during dialysis

Scratching of the puncture site

Poor personal hygiene

Contamination due to bathing.

83

84

Management:

Must be managed urgently as it can lead to

thrombosis or sepsis if left untreated.

Do not cannulates

Bloods cultures must be obtained and the access

site swabbed to confirm diagnosis.

Antibiotics mostly necessary.

Patient may need admission and temporary dialysis

access

85

Prevention:

1. Pre and post treatment washing of access

2. No scratch on the access site

3. Appropriate skin antisepsis

4. Sufficient antiseptic-skin contact time

5. Cannulation while antiseptic is dry

6. Maintain needle sterility

7. Do not cannulate through scabs or abraded

areas

86

3-Thrombosis (clotting)The most common complications of AVF.

Venous stenosis resulting in reduced blood flow,

infection, recirculation, damage to the vessel wall, and

eventually clotting of the fistula.

87

Causes

Surgical/technical problems

Preexisting anatomic lesions

Premature use

Poor blood flow or hypotension

Hypercoagulation

Fistula compression (Patient compressing

while sleeping)

88

Clinical

Absence of pulse/thrill on palpation ( feel firm)

Absence of bruit on auscultation

No blood or blood clots can be aspirated

89

Management ( Urgent treatment is required to

prevent the failure of the access)

Do not needle

Take blood sample to see if HD necessary

Inform the nephrology team immediately.

Interventional thrombolysis

Surgical thrombectomy

Prophylactic surveillance (warfarin)

May require new access

90

4-BleedingCauses

Bleeding after remove needle

Anticoagulation/not stopping prior to end of HD

Improper pressure with needle withdrawal

Bleeding during treatment (oozing around needle

or infiltration) = fragile vessel wall or back wall

penetration don’t flip the needles

91

Symptoms and signs

Needle sites bleed >10mins following HD

92

Management:

Stop anticoagulation 1hr prior to the end of HD

Apply directed pressure

Consider coagulants (Protamine sulfate)

Review needle-removal technique

Review clotting disorder

Review medications and BP

Educate patients about post-treatment hemostasis

and what to do at home ,if the needle site re-bleed

93

5-Infiltration = Hematoma

The pathological accumulations of substances in

tissue or cells which are normally are absent.

Causes: an improper needle flip or taping procedure

can cause an infiltration.

94

How to prevent the infiltration:

During cannulation

Don’t flip needle

Don’t lift needle in vein

Check for flashback and aspirate

Flush with NSS to ensure, that there are no signs

or symptoms of infiltration (Saline causes much

less damage and discomfort than blood if an

infiltration occurs)

95

Post hemodialysis

Apply gauze without pressure during

removal of needle

Remove needle at insertion angle

Apply pressure with 2 fingers

Hold pressure 10–12 minutes

96

Management of infiltration:

Elevate arm above heart

Ice 20 minutes on/20 minutes off for 24 hours

Warm compresses after 24 hours

Let fistula rest

Second infiltration: Notify vascular access team

97

Hematoma

If bruising or hematoma occurs after dialysis, the

surface skin site has sealed but the needle hole in

the vessel wall has not.

Use 2 fingers per site for hemostasis

It is crucial to apply pressure to both the skin and

access wall puncture sites

98

6-Poor arterial flow and increased venous

pressure

May be due to location or position of needle

May be there are thrombosis or stenosis or

significant recirculation.

This poor flow may lead to clotting of the AVF.

99

Management:

An angiogram or Doppler US should be performed to

detect stenosis or thrombosis.

Recirculation tests can also be used to determine the

significance of venous stenosis.

Recirculation >10–15% suggests access malfunction.

R = {(P – A) / (P – V)}x 100

P= BUN periphery, A= BUN arterial line,

V= BUN venous line and R =the percentage

recirculation

100

7-Stenosis:Most common complication

Hyperplasia in lumen (usually arterial side)

Frequent cause of fistula failure

Causes:

Surgery to create AVF

Turbulence-Pseudoaneurysm-aneurysms

Needle-stick injury

101

Type of stenosis:

1-Juxta-anastomotic (most common stenosis in AVF)

2-Mid-access stenosis

3-Outflow stenosis

4-Central vein stenosis

102

Clinical key that there is stenosis:

Clotting of the extracorporeal circuit 2 or more

times/month

Persistently swollen access extremity

Changes in bruit or thrill (ie, becomes pulse-like)

Difficult needle placement

Blood squirts out during cannulation

Elevated venous pressures

103

Inability to achieve optimum blood flow rate.

Changes in Kt/V and URR

Recirculation

Prolonged postdialysis bleeding

Presences of frequent episodes of access clotting

104

Diagnosis

Physical examination and/or flow measurement

should be performed as soon as possible.

Duplex scan/fistulagram.

MRA should be performed

Recirculation studies

R = ([P - A] / [P – V]) x 100

Where P= BUN periphery, A= BUN arterial line, V=

BUN venous line and R =the percentage

recirculation

105

Parameter Normal Stenosis

Thrill Only at the arterial anastamosis

At site of stenotic lesion

Pulse Soft, easily compressible

Water-hammer

Bruit Low pitch, ContinuousDiastolic & systolic

High pitch, DiscontinuousSystolic only

106

Management

Call surgical team for corrective treatment:

Percutaneous trans-luminal angioplasty is the first

treatment option for venous outflow stenosis.

Radiological intervention ( stent or balloon

dilatation)

Surgical revision.

Temporary access

107

Steal syndrome: Deprivation of blood distal to

AVF/AVG

Steal syndrome (ischemia of the hand)

Inadequate blood supply to the hand, caused by

the AVF “stealing” blood away from the

extremity, this causes hypoxia (lack of oxygen)

to the tissues of the hand resulting in severe pain

and neurologic damage to the hand can occur.

108

Risk factors

Brachial arterial origin

Diabetes mellitus

Peripheral vascular disease (PVD)

Female gender

109

Clinical picture: Most patients are asymptomatic

Cold sensation and pale colour of the fingers

Ischemic pain

Diminished or absent pulses

Capillary refill will decrease

Neurological and soft tissue damage to the hand can

occur, resulting in mobility limitations (eg, grip

strength, skill), loss of function, ulcerations, necrosis

110

111

Diagnosis of Steal Syndrome

Clinical investigation –Allen test.

Noninvasive imaging tests: measurement of

digital pressures and access flow

measurements.

Angiography

Pulses, BP, pulse oximetry, Doppler, duplex

US should be carried out.

112

Allen test.

A medical sign used in physical examination of

arterial blood flow to the hands.

The hand is normally supplied by blood from both

the ulnar artery on the little finger-side and the

radial artery on the thumb-side.

113

These two arteries connect to form an anastomosis,

so if one of the arteries becomes compressed or

occluded, the blood supply from other artery will

maintain the blood supply of hand

Compressing both the radial and ulnar arteries

simultaneously (30 second ) while patient open and

close his hand, allowing the blood to drain via the

venous system, causing the hand to blanch.

114

While the patient opens and closes his hand, release

one of the arteries, evaluating how fast refill occurs

to the hand.

Repeat the procedure again, this time releasing the

other artery while timing the refill.

Refilling of less than 3 seconds is considered a

negative test and indicates there is adequate blood

flow in the palmer

115

116

Management of Steal Syndrome

Early referral to the surgical for revision of access

the DRIL distal revascularization-interval ligation,

can successfully treat steal and ischemia

Pain control.

Encourage patient to wear a glove on affected

extremity.

Steal symptoms may improve due to the

development of collateral circulation.

117

Examination of the mature hemodialysis arteriovenous fistula

118

Routine physical examination of the fistula lead to

early detection and treatment of any problems

The 2006 National Kidney Foundation Kidney

Disease Outcomes Quality Initiative

(NKF-K/DOQI) guidelines and the 2008 Society

for Vascular Surgery practice guidelines

recommend that physical examination must be

performed on all mature arteriovenous fistulas

(AVFs)

119

Examination must be done every hemodialysis

treatment.

Must be known by all clinical staff who dealing

with fistula

It is easy

Inexpensive

To detect common problems associated with

hemodialysis access

120

Inspection

Position of the fistula

1. Radiocephallic

2. Brachiocephallic

3. Transposed cephallic

Presence of other vascular access

1. Central venous access

2. Peritoneal access

3. Graft

121

Expose the entire extremity with the AV access

Compare any change in the limb to the non-access

limb

Signs of infection (warmth, erythema, discharge ...)

Presence of bruising (hematoma) , swelling

(edema), and collateral veins (visualize entire arm

and upper chest)

Aneurysm and pseudoaneurysm

122

Outflow stenosis (Arm Elevation Test): When the

access arm is elevated to a level above the heart.

o The absence of a stenosis, the vein where the blood

flows out

(Should collapse , Become less prominent)

o If a stenosis is present, the portion of the fistula

distal to point of stenosis remains distended, while

the proximal portion collapses

123

124

Access-induced ischemia or steal syndrome (signs

of cyanosis of the finger tips and delayed capillary

refill of the nail beds, hand pallor and decreased

range of motion)

Location of anastomosis and evidence of healing

incision lines

Skin integrity (rash, blisters, scabs or eroded

cannulation sites)

125

Appropriateness of vessel size (depth and diameter)

for cannulation suitability

Location for previous cannulation sites (avoid thin,

white, shiny aneurysmic areas).

Central venous stenosis: (If generalized swelling of

the arm and/or collateral veins on the upper limb is

identified, the possibility of central venous stenosis

needs to be ruled out)

126

Palpation for AV fistula

Evaluate for possible cannulation sites =

superficial, straight vein section with adequate and

consistent vein diameter

Feeling of fistula

Use a two- or three-finger approach to roll fingers

across the AV fistula to determine width and depth

of access

Check for tenderness

127

Pulse

o Normal AVF is soft, compressible and non-

pulsatile

o A pulsatile fistula is suggestive of obstruction or

stenosis (venous side).

o The strength of the pulse is related to the severity

of this obstruction

128

129

Temperature Change

Feel the access skin temperature

o Warmth = possible infection

o Cold = decreased blood supply

Assess and compare temperatures in both the

access and non-access limb.

130

The thrill must be assessed by palpating the entire

length of the AV fistula to determine access patency

(The vein should be soft and easy to compress)

Normally a thrill has a systolic and a diastolic

component

A thrill is a buzzing or vibration felt (soft continuous

thrill)the blood flow created by the high pressure

arterial system merging with the low pressure venous

system}

131

A strong thrill should be palpable at the arterial

anastomosis diminishing distally, closer to the venous

end.

Change can be felt at the site of a stenosis; becomes

‘pulse-like’ at the site of a stenosis

A weak thrill may suggest a stenosis at or near the

anastamosis (arterial side)

132

Occasionally, a thrill can be palpated in the axillary

or subclavian region, particularly in thin chested

individuals and may suggest presence of central

venous stenosis.

133

Pulse augmentation test ( for inflow stenosis) The normal AV access is soft and compressible but

non-pulsatile.

If the access occluded several centimeters above the

anastomosis, there should be augmentation of the pulse

in the distal portion.

The degree of this “pulse augmentation” is

proportional to arterial inflow pressure, making this

maneuver, an excellent tool to diagnose inflow

problems.

134

If the pulse augmentation is poor ( weak or absent

pulse with obstruction ) poor arterial inflow

135

Auscultation Listen for Bruit

Begin at the AV anastomosis and continue along the

length of the access noting any changes in pitch and

amplitude of the bruit.

Bruit: A well-functioning fistula should have

continuous, machinery-like bruit on auscultation (low-

pitched whooshing of blood through the fistula heard

through a stethoscope) created by the turbulence at the

anastamosis.

136

An obstructed (stenotic) fistula may have a

discontinuous and pulse-like bruit rather than a

continuous one and also may be louder and high-

pitched or ‘whistling’ Louder at stenosis than at

anastomosis

Absent bruit usually indicates that the access has

clotted or thrombosed.

NO bruit – NO cannulation

Portable ultrasound to make good report about AVF.

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