Fistula (Arteriovenous fistula -AVF)

Subcutaneous anastomosis (communications)
of an artery to a vein, allowing blood flow
directly moves from artery to vein
Arteriovenous fistula (AVF)
2

 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 vein 4

Advantages of AVF
Lower 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 AVF
1. 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 limb
7

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
9

1.Radial–cephalic AV fistula ( wrist )
10

2.Brachial–cephalic AV fistula (elbow)
11

3.A transposed brachial basilic vein fistula
12

•Pre-operative care in hand for AVF
This 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
14

Post-Operative care of AVF or AVGs
Immediately 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

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 Preparation
Patients 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

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

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 length
1. 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

 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

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 eye
The 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

Bevel position/ flipping of needle
Angle 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 needle
46

 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 Hemostasis
Needles 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 hemostasis
49

 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
53

Complicationsof 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 HD
Needle 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

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 haemostasis
Most 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.

68
“ONE-SITE–ITIS”
Occurs when cannulates the needle in the same
general area, session after session
Causes aneurysm and stenosis formation

69
Buttonhole Technique
Method 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

76
1-Aneurysm , Pseudo aneurysm
A 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.

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-Bleeding
Causes
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

105
Parameter Normal Stenosis
Thrill Only at the arterial
anastamosis
At site of stenotic
lesion
Pulse Soft, easily
compressible
Water-hammer
Bruit Low pitch,
Continuous
Diastolic & systolic
High pitch,
Discontinuous
Systolic 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

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

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
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

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

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

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.

Fistula (Arteriovenous fistula -AVF)

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Fistula (Arteriovenous fistula -AVF)