VASCULAR
ACCESS
AVF and AVG
bautistawil
OBJECTIVES
Upon completion of this topic, the learner will be able to:
1.
2.
3.
Describe the advantages and disadvantages of various type of vascular access
Identify potential complications connected with each type of vascular access
Provide adequate and appropriate education to patients and their significant others.
2
bautistawil
Significant Dates in the History of the
Vascular Access
bautistawil
AV SHUNT
1960: Scribner and Quinton developed the first permanent access.
4
bautistawil
AV FISTULA
1966: Brescia and Cimino developed the internal arteriovenous (AV) fistula
for repeated venipunctures for maintenance HD.
bautistawil
AV GRAFT
1974: Bovine carotid artery graft used for circulatory access
1975: Gore-tex® graft became commercially available for use as AV access for HD
1977: Umbilical cord vein used for AVF graft
1977: Expanded polytetrafluoroethylene (ePTFE) used as AV access for hemodialysis
6
bautistawil
Preparing for Vascular Access for
Hemodialysis
bautistawil
I. Anatomy of the vascular access for hemodialysis
A. The venous system in the upper extremity includes both superficial and
deep veins. It is superficial system that is most important for access
creation.
B. The radiocephalic AVF at the wrist is the first choice hemodialysis access
and uses the forearm segment of the cephalic vein.
8
bautistawil
Anatomy of the Upper Extremity Vessels
9
bautistawil
II. Patient Evaluation
A. Assessment, Evaluation and Preservation
1. Patiet GFR less than 30 mL/min/1.72m² (CKD Stage 4)
2. Early referral for permanent dialysis access.
3. Preservation of veins of the forearm and upper arms.
4. Recommended timeline
1.
2.
AVF should be placed 6 months prior to anticipated need
AVG should be inserted at least 3 to 6 weeks ahead of anticipated need
5. Nurse play crucial role in educating, explaining and reassuring patients.
10
bautistawil
II. Patient Evaluation
B. Evaluation Prior to Access Placement
1. Helps to optimize access survival while minimizing potential complications
2. Evaluations should include:
1.
2.
History and physical examination
Dupplex ultrasound of the upper extremity blood vessels
11
bautistawil
III. Selection and Placement of the Vascular Access
1. Arteriovenous Fistula
2. Arteriovenous Graft
3. Central Venous Catheter
A. Non Tunneled CVC
B. Tunneled CVC
12
bautistawil
NKF KDOQI, 2006, Clinical Practice Guidelines (CPG)
Vascular access should be placed distally and in the upper extremities
whenever possible. Because AVF provides the access with the longest
patency rates and need for fewest interventions; options for AVF creation
should be considered first, followed by prosthetic grafts, if AVF creation is
not possible. Catheters should be avoided for HD and used only when the
previous options are not possible, are contraindicated by the patient’s
condition, or the access for hemodialysis is short term
13
bautistawil
The ARTERIOVENOUS FISTULA (AVF)
bautistawil
Definition:
A surgically created opening between an artery anastomosed to a
juxtapositional (nearby) vein allowing the high pressure arterial
blood to flow into the vein causing:
VEIN ARTERIALIZATION
a.
b.
c.
Engorgement
Enlargement
Wall thickening.
bautistawil
Types of Anastamosis
bautistawil
PLACEMENT OF AVF
(in order of priority)
1.
2.
3.
Wrist (radial-cephalic) primary fistula
An elbow (brachial-cephalic) primary fistula.
An upper arm (brachial-basilic) fistula with vein transposition (surgically
dissecting out and tunneling in a superficial, accessible area)
bautistawil
Radiocephalic Arteriovenous Fistula
bautistawil
Snuff-box Arteriovenous Fistula
bautistawil
Proximal Forearm Arteriovenous Fistula
bautistawil
Brachiocephalic Arteriovenous Fistula
bautistawil
Transposed Basilic Vein Arteriovenous Fistula
bautistawil
Assessment for Fistula
ALLEN TEST
1.
Patient clenches the fist of one hand to
produce pallor in the hand
2.
Clinician occludes arterial flow by
compressing both radial and ulnar arteries
3.
4.
Patient opens clenched fist
Clinician releases pressure on the ulnar
artery and counts the seconds required for
color to return to the hand. More than 3
seconds indicates decreased ulnar arterial
supply to the hand if the radial artery is used
for the vascular access
bautistawil
5. Repeat the procedure, but release pressure
on radial artery this time to assess radial
arterial flow to hand.
6. Repeat procedure with opposite hand.
ALLEN TEST
bautistawil
bautistawil
ADVANTAGES OF AVF 1
1. Average problem-free patency period is approximately 3 years.
2. The long-term secondary patency rate:
1.
2.
7 years for forearm fistula
3-5 years upper arm fistula
3. Lowest rate of thrombosis
4. Lower rates of infection than grafts
5. Cost of implantation and access maintenance are the lowest long-term
26
bautistawil
ADVANTAGES OF AVF 2
6. Associated with increased patient survival and lower hospitalization rates.
7. Avoid potential allergic response to synthetic materials
8. Outflow veins are autogenous tissue that seal and heal after cannulation.
9. Can use buttonhole cannulation technique.
27
bautistawil
DISADVANTAGES OF AVF
1. The vein may fail to enlarge or increase wall thickness (i.e., fail to mature)
2. Long maturation time
3. Some individuals, the vein may be more difficult to cannulate.
4. A thrombosed AVF may be more difficult to restore the flow.
5. Cosmetically unattractive
6. Increase cardiac output.
28
bautistawil
RULE OF 6 for AVF MATURATION
• The vessel should be greater than 6mm in diameter
• The vessel should be less than 6 mm from surface
• Flow through the vessel should exceed 600mL per min.
• AVF should be expertly assessed within 6 weeks of creation for maturation
29
bautistawil
ASSESSMENT OF THE FISTULA
LOOK
LISTEN
FEEL
30
bautistawil
1. INSPECTION - Look
A. Compare the access extremity with the other extremity.
B. Asses the access extremity for:
1.
2.
3.
4.
5.
6.
Swelling
Presence of collateral veins
Change in color or temperature
Decreased sensation
Limitation of movement
Capillary refill time
C. Assess the fistula itself.
31
bautistawil
2. AUSCULTATE - Listen
BRUIT – continuous “whooshing”
NORMAL AVF
sound caused by the turbulence at
the anastomosis
•
Note change in the sound or character of
the blood flowing through the fistula.
bautistawil
AVF with STENOSIS
3. PALPATE - Feel
To determine the blood is flowing through the fistula
Thrill – Sensation that felt over the fistula
a) A continuous vibration
b) Result of turbulence created by the blood flow
c) Pulsatile thrill may indicate stenosis
bautistawil
PATIENT TEACHING
• Reinforce and expand pre-AVF placement education to avoid
venipunctures and blood pressure measurements in targeted arm.
• Elevate affected arm to decrease post-op swelling
• Exercise for vessel development
bautistawil
PATIENT TEACHING
•
Instruct the ff:
- How to palpate “thrill”
- Avoid sleeping on access extremity
•
•
•
•
bautistawil
Avoid wearing anything that would tightly
encircle the access extremity
Wash area with soap and water before
cannulation
How to stop bleeding – apply localized
pressure
How to recognize and report s/s of infection or
absence of thrill / bruit
The ARTERIOVENOUS GRAFT (AVG)
bautistawil
ARTERIOVENOUS GRAFTS (AVG)
• DEFINITON: A synthetic or, less frequently,
biologic conduit implanted subcutaneously and
interposed between an artery and a vein.
• Needles are inserted into the graft (never into the
anastomoses) to remove and return blood during
hemodialysis. The average graft is 6 mm.
bautistawil
INDICATIONS of AVG
•
•
Patients who do not have vasculature suitable for AVF
or who have failed AVF in the location of the planned
AVG.
AVG is second best option for hemodialysis
bautistawil
TYPES OF GRAFT
1. Synthetic Grafts
2.Composite/ Polyurethane Graft
3. Biologic Graft
bautistawil
ANATOMIC LOCATIONS of AVG
1.
2.
3.
A forearm loop graft
4.
Lower extremity graft.
Upper arm graft
Chest wall or “necklace” prosthetic
graft
bautistawil
FOREARM LOOP ARTERIOVENOUS GRAFT
41
bautistawil
UPPER ARM ARTERIOVENOUS GRAFT
42
bautistawil
THIGH ARTERIOVENOUS GRAFT
43
bautistawil
AVG Surgery
bautistawil
bautistawil
ADVANTAGES OF AVG
• Larger surface area for cannulation
• Easier to cannulate
• Time for surgical insertion to
maturation is short
•
•
bautistawil
ePTFE 1-3 weeks prior to cannulation
Time allows for healing and the
incorporation of the surrounding tissue
ADVANTAGES OF AVG
• AVG can be placed in many areas of
the body
• Can be placed in a variety of shape
to facilitate placement and
cannulation
• Graft is easier to repair
bautistawil
DISADVANTAGES OF AVGs
1.
2.
3.
4.
Higher rate of stenosis and thrombosis
Higher rate of infection
Higher mortality
Shorter length of patency
1.
Last 1-2 years before indication of
failure or thrombosis
2.
Long-term patency rate with treatment
of stenosis and thrombosis remains at 2
years
bautistawil
DISADVANTAGES OF AVGs
5. Cannulation sites seal but not heal
6. Allergic response to the material
7. Steal syndrome
bautistawil
Patient Teaching
1. Instruct to elevate and abduct extremity and use
the hand normally as much as possible
2. No venipunctures / BP taking in the access arm
3. Avoid sleeping on the access extremity
4. Wash area with soap & water before cannulation
5. Report any s/s of infection and absence of thrill /
bruit
bautistawil
VASCULAR ACCESS COMPLICATIONS
bautistawil
Access Complications
A. BLEEDING
B. INFECTION
C. VENOUS STENOSIS
D.CENTRAL VENOUS STENOSIS
E. THROMBOSIS
F. ANEURYSM / PSEUDOANEURYSM
G.STEAL SYNDROME
bautistawil
A. BLEEDING / INFILTRATION
DEFINITION
•
•
•
Inadvertent administration of fluid into
tissue surrounding the fistula.
Secondary to improper cannulation
technique
Can occur before, during or after dialysis
bautistawil
A. BLEEDING / INFILTRATION
SIGNS AND SYMPTOMS
• Edema
• Taut or stretched skin
• Pain
bautistawil
A. BLEEDING / INFILTRATION
PREVENTIONS
•
•
•
•
Monitor closely for signs and
symptoms of infiltration
Use caution when taping needles
Monitor arterial and venous pressure
Proper needle removal
bautistawil
B. INFECTION
CAUSES
•
•
•
•
•
Staphylococcus Aureus is the leading cause
Poor patient hygiene
Inadequate skin preparation
Not using aseptic technique
Seeding from another infected site in the
body
bautistawil
B. INFECTION
SIGNS AND SYMPTOMS
•
•
•
•
bautistawil
Inflammation
Pain
Skin break with drainage along the
course of vessel
Fever
C. VENOUS STENOSIS
DEFINITION
Abnormal narrowing of the lumen of the
vessel as a result of injury to the wall,
causing intimal hyperplasia
•
•
•
Bruit changes to a choppy
At the site of stenosis, bruit may be
higher pitched
Pulse will become a harsher, water
hammer feel
bautistawil
C. VENOUS STENOSIS
RELATED ABNORMALITIES
1.
Reduction in BFR and potential
clotting
2.
3.
4.
Increase static venous pressure
Access recirculation
Unexplained reduction in KT/V
bautistawil
C. VENOUS STENOSIS
CLUES INDICATING STENOSIS
bautistawil
1.
2.
3.
Inability to maintain BFR
4.
Increase bleeding time post dialysis
Increased venous pressure
Difficulty cannulation or having
blood squirt out
C. Venous Stenosis
POTENTIAL INTERVENTIONS AND TREATMENT
1. Non invasive technique to
assess a fistula
2. Doppler ultrasound or
fistulogram
• Detect stenosis
• Measure stenosis
3. Baloon angioplasty
4. Stent placement
bautistawil
D. CENTRAL VENOUS STENOSIS
CAUSES OR CONTRIBUTING FACTORS
•
•
•
•
bautistawil
History of multiple central venous
catheter
Mechanical compression of the
central venous system
Arterialized high flow in the central
veins
Some without an identifiable cause
D. CENTRAL VENOUS STENOSIS
SIGNS and SYMPTOMS
1. Massive swelling in the upper
extremity
2. Extensive network of collateral veins
3. Pain and discomfort during dialysis
session
bautistawil
D. CENTRAL VENOUS STENOSIS
POTENTIAL INTERVENTIONS AND TREATMENT
1. Prevention through avoidance of
subclavian inserted catheters.
2. Transluminal angioplasty with
possible stent placement
3. Surgical treatment is very complex
and reserved for extreme situations.
bautistawil
E. THROMBOSIS
CAUSES
1.
Stenosis of main outflow vein
without collateral circulation
2.
Significant hypotension due to
volume depletion
3.
4.
5.
Hypercoagulable states
Prolonged occlusive compression
Supporting heavy objects
bautistawil
E. THROMBOSIS
SIGNS and SYMPTOMS
•
•
•
•
•
Vein distended and does not soften
when arm is elevated overhead
Significant decreased intra-access
blood flow
Changes in quality of the bruit
Difficulty or pain with cannulation
Evacuation of clots
bautistawil
E. THROMBOSIS
POTENTIAL INTERVENTIONS AND TREATMENT
•
•
•
•
bautistawil
Urgent referral to a surgeon
Lysing the clot with a thrombolytic
such as tPA
Thrombectomy
Anticoagulation therapy
F. ANEURYSM / PSEUDOANEURYSM
CAUSES
•
Cannulating in the same area
“one-site-itis”
•
•
Outflow stenosis / occlusion
Persistent hypotension
bautistawil
F. ANEURYSM / PSEUDOANEURYSM
SIGNS and SYMPTOMS
•
•
•
Vessel enlargement
Dilatation on the weakened
vessel wall
Possible changes in bruit
bautistawil
F. ANEURYSM / PSEUDOANEURYSM
POTENTIAL INTERVENTIONS AND TREATMENT
•
•
•
Assessing AVF every treatment
Education of the staff
Surgery based on severity
bautistawil
E. STEAL SYNDROME
CAUSES
•
•
Ischemia of the extremity distal to
arterial anastomosis
Diversion of significant volume of
blood away from peripheral
circulation
bautistawil
•
Occurs more frequently in patients
who:
•
•
•
•
Elderly
Have peripheral vascular disease
Have diabetes
Have history of multiple access surgeries
E. STEAL SYNDROME
SIGNS and SYMPTOMS
•
•
•
•
•
•
bautistawil
Pain distal to anastomosis
Cold, pale hand
Impaired hand movement and strength
Paresthesias: numbness, tingling
Poor capillary refill
Progression to ulcerated, necrotic
fingertips
E. STEAL SYNDROME
POTENTIAL INTERVENTIONS AND TREATMENT
•
•
•
•
•
Report any abnormal findings
Surgical reperfusion of the hand using the DRIL
Banding of inflow to the graft to reduce flow
Severe ischemia may require urgent ligation of
the access
Mild ischemia may improved by wearing of a
glove, exercising, and/or massaging
bautistawil
References
• Kallenbach, J.; Review of Hemodialysis for Nurses and Dialysis Personnel,
8th Edition. Elsevier Health Sciences, 2012
• Counts, C.; Core Curriculum for Nephrology Nursing, 6th Edition. ANNA
(American Nephrology Nurses Association), 2015
• Vachharajani, T.; Atlas of Dialysis Vascular Access, 2010
74
bautistawil
bautistawil
bautistawil