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VASCULAR ACCESS IN HEMODIALYSIS

Dr. IRFAN ELAHI

Consultant Nephrologist

Mayo Hospital Lahore

BY

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Native Arteriovenous fistula (AVF)

Prosthetic arterio-venous graft (AVG)

Cathater

Temporary double lumen cathater

Permanent Cathater

THERE ARE 3 TYPES OF VASCULAR ACCESS

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A V GRAFTS

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Benefits of Arteriovenous Fistula (AVF)

Lowest rate of failures and complications

Longevity

Lowest costs

BENEFITS OF ARTERIOVENOUS FISTULA (AVF)

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Definition

Process by which a fistula becomes suitable

for cannulation (ie, develops adequate flow,

wall thickness, and diameter).

FISTULA MATURATION

Rule of 6’sIn general, a mature fistula should:

Be a minimum of 6 mm in diameter with discernible margins when a

tourniquet is in place

Be less than 6 mm deep

Have a blood flow greater than 600 mL/min

Be evaluated for non maturation 4–6 weeks after surgical creation

FISTULA MATURATION

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The fistula should be examined regularly following

surgery. At 4 weeks post surgery, the fistula should be

evaluated specifically for non maturation.

CLINICAL CLARIFICATION

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Look, listen, and feel the new AVF at every dialysis treatment

After the scar heals, begin assessing AVF using a “gentle”

tourniquet placed high in the axilla area

Instruct patient to start access exercises after healing

Document patient education as well as condition and

maturation of the AVF

DURING AVF MATURATION PROCESS

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Vessel diameter must be 4–6 mm

Vessel walls should toughen and be firm to the touch

There should be no prominent collateral veins

MATURING FISTULA

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TOURNIQUET

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IS NEW AVF MATURE AND READY FOR CANNULATION?

AVF

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Vein looks large enough

Vein feels prominent and straight

Vein has a strong thrill and good bruit

IS AVF MATURE AND READY FOR INITIAL CANNULATION?

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What diagnostic tools or techniques can be used

to determine if an AVF is ready for cannulation?

Can the same tools or techniques be used to

select the cannulation sites?

FISTULA MATURATION

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Duplex Doppler study Physical exam by the: Nephrologist Nephrology nurse Surgeon Angiogram (fistulogram)

DIAGNOSTIC TOOLS/TECHNIQUES TO DETERMINE IF AN AVF IS READY

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Physical ExamLook, Listen, and Feel Using;

Eyes

Ears

Fingertips

BEST TOOL/TECHNIQUE?

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Physical Exam

Firm, no longer mushy

Vessel wall thickening

Vessel diameter enlargement (to 4–6 mm)

Absence of prominent collateral vein

If in doubt, “Just Say No”

MATURING FISTULA

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Look for Changes compared to opposite extremity Skin color/circulation Skin integrity Edema Drainage Vessel size/cannulation areas Aneurysm Hematoma Bruising

INSPECTION

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Temperature Change

Warmth = possible infection

Cold = decreased blood supply

PALPATION

Thrill

PALPATION

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Palpation can be started at the anastomosis

Thrill diminishes evenly along access length

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

“pulse-like” at the site of a stenosis

Stenosis may also be identified as a narrowed area

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Feel for Size, Depth, Diameter, and Straightness of AVF

Feel the entire AVF from arterial anastomosis all the way

up the vein

Evaluate for possible cannulation sites = superficial,

straight vein section with adequate and consistent vein

diameter

PALPATION

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Listen for Bruit Listen to entire access every treatment Note changes in sound characteristics (bruit):

A well-functioning fistula should have a continuous, machinery-like bruit on auscultation 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

AUSCULTATION

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Communicate assessment findings with access team,

including surgeon

Check maturity progress every session

Assure evaluation by surgeon 4 weeks post-op

Intervene if there is no progress at 4 weeks or AVF is not

mature and ready for cannulation at 6–8 weeks

POST-OP FOLLOW-UP

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Must have:

Physician’s order to cannulate

Experienced, qualified staff person who is successful with new

fistula cannulations

Use of a tourniquet or some form of vessel-engorgement

technique (e.g, staff or patient compressing the vein)

BASIC REQUIREMENTS FOR CANNULATION

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17-gauge needle is strongly recommended for initial cannulation A fistula may appear and feel ready to cannulate, but the vessel wall may still be fragile and unable to tolerate the needle puncture The smaller needle gauge helps to decrease injury to the vessel and prevents a large infiltration, hematoma, compression of the vessel, and possible clotting of the AVF should any cannulation complication occur (ie, infiltration)

NEEDLE GAUGE

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MATCH NEEDLE GAUGE TO BLOOD FLOW RATE (BFR)

Needle Gauge Maximum BFR

17-gauge < 300 mL/min

16-gauge 300-350 mL/min

15-gauge 350–450 mL/min

14-gauge > 450 mL/min

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USE BACK-EYE NEEDLES

Back-eye opening allows blood intake from both

sides of the needle; can be used as arterial or

venous needle

Non–back-eye needle—for

venous use only

Arterial needle Venous needle

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BACK-EYE NEEDLE FLOW

Allows blood toenter or exit from

both the bevel and back-eye

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Always cannulate the venous needle with the

direction of the blood flow

Always cannulate the arterial needle cannulation

toward the blood inflow or with the blood

outflow

NEEDLE DIRECTION

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Venous needle

directed back

toward the heart

Arterial needle

directed toward the

arterial anastomosi

s (retrograde)

Needle Direction

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Venous needle

directed back

toward the heart

Arterial needle also

directedback toward

the heart (antegrade)

Needle Direction

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Always use a tourniquet, regardless of the size or

appearance of vessel

Use of the tourniquet helps to engorge, visualize, palpate,

and stabilize the AVF

Use 20–35° angle for needle insertion for an AVF

NEW AVF CANNULATION PROTOCOL

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“WET” NEEDLE

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On removal of needles, for hemostasis:

Use 2-finger compression

Never use clamps

Hold sites for 10 minutes—no peeking

NEW AVF CANNULATION: ADDITIONAL POINTS

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Check fistula daily for a thrill and bruit

Check for signs and symptoms of infection or other

complications

Write instructions for fistula care

EDUCATION FOR PATIENTS

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Thrill is undetectable

Patient becomes feverish, dehydrated, or

experiences low blood pressure

CALL THE NEPHROLOGIST/PHYSICIAN

CANNULATION SITE SELECTION AND PREPARATION

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Assess AVF before every cannulation Compare arms for changes in skin color, circulation, integrity Inspect

Access extremity for central or outflow vein stenosis Distal areas of extremity for steal syndrome Access for vessel size, cannulation areas, infection, aneurysms

PHYSICAL ASSESSMENT

PHYSICAL ASSESSMENT

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Palpate

Temperature change may mean infection or stenosis

Change in thrill may mean stenosis

Auscultate

Listen to entire access for changes in bruit that indicate

stenosis

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Look and feel for a straight segment of AVF Segment must be as long as the needle length (ie, 1″ minimum) Stay at least 1.5″ from the AVF anastomosis The arterial and venous needles need to be 1″ to 1.5″ apart Avoid curves, flat spots, and aneurysms to prevent complications

IDENTIFY IDEAL SEGMENT OF AVF

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Dialysis patients have more Staphylococcus spp (SA and

MRSA) on their skin and in their nares (nose) than the

general population

Dialysis staff can also have a higher rate of staph carriage

Common route of transmission of staph is from the nose

to the skin to the vascular access = infection

SITE PREPARATION

If possible, patient should

wash the access with

antibacterial soap before

coming to the chair

Staph is the leading cause

of infection in dialysis

patients

SKIN PREPARATION

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Proper needle-site preparation by both the patient and staff reduces infection rates Once the skin site is properly cleansed, the skin should not be touched with bare hands or gloved hands

If touched, re-prep the skin All site selection should be done prior to the final skin preparation

SKIN PREPARATION

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Wet insertion site for 30 sec Allow to air-dry for ≈30 sec Do not blot or wipe

APPLYING CHLORHEXIDINE GLUCONATE

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Saturate sterile gauze pad Clean sites with circular motionWait 2 minutes before proceeding

APPLYING SODIUM HYPOCHLORITE

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Proper needle-site preparation reduces infection rates Start where you are going to place the needle (the black dot) and cleanse in a circular, outward motion Do not touch skin after cleansing area

PROPER CLEANSING TECHNIQUE

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KDOQI Says

For all vascular accesses,aseptic

technique should be used for all

cannulation and catheter

incertion procedures (evidence)

SAYS WHO? 1. Locate, inspect and palpate the

needle cannulation sites prior to skin preparation. Repeat prep if the skin is touched by the patient or staff once the prep has been applied, but the cannulation not completed.

2. Wash access site using an antibacterial soap or scrub and water.

3. Cleanse the skin by applying 2% chlorhexidine gluconate/70% isopropyl alcohol and/or 10% povidone iodine as per manufacturer’s instructions for use.

Notes: 2% chlorhexidine gluconate/70%

isopropyl alcohol antiseptic has a rapid (30 s) and persistent (up to 48 hr) antimicrobial activity on the skin. Apply solution using back and forth friction scrub for 30 seconds. Allow area to dry. Do not blot the solution.

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Needle fear and pain with needle insertion are very real issues for many hemodialysis patients Various pain-control options can be utilized to make the cannulation procedure less stressful for patients

ANESTHETIC OPTIONS FOR PAIN CONTROL

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Lidocaine injected under the skin and above the vessel Advantage: Numbs the area prior to the cannulation procedure Disadvantages: Can cause scarring, vasoconstriction, keloid formation,burning with injection, and poses a needle-stick risk

INTRADERMAL ANESTHETICS

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Topical sprays (ethyl chloride) can be used to numb the skin sites Advantage: Noninvasive method of numbing the skin Disadvantages: Nonsterile, requires patient-specific bottle to prevent cross-contamination, may discolor or damage skin with long-term use, flammable contents in bottle Method: Spray arterial site, prep skin, then insert needle immediately; repeat for venous site

TOPICAL SPRAYS

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Wash skin first Apply 1 hour before dialysis Cover with plastic wrap Prior to cannulation, remove cream, wash/prep skin

USING TOPICAL CREAMS

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Tourniquet required for all cannulations Apply tightly enough to engorge vessel

TOURNIQUET USE

CANNULATION TECHNIQUES

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Site-RotationAlso known as:

Rope ladderRotating sites

CANNULATION TECHNIQUES

ButtonholeAlso known as:

Constant-siteSame-site

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Take your timeCannulation is achieved in a gentle mannerDetermine the depth of the access during your assessment—this will determine the angle of entry into the fistula

IMPORTANT TIPS

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Cannulation sites are rotated up and down the AVF to use its entire length Classic technique used in most dialysis centers

SITE-ROTATION TECHNIQUE

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Look for straight areas of at least 1″ for each cannulation site If you try to “straighten out” by pulling on the vessel to cannulate, the vessel will retract into its original position when released and lead to an infiltration Avoid aneurysms and flat or thinned-out areas Stay 1.5″ away from the anastomosis Keep the needles at least 1.5″ apart Each treatment requires 2 new sites

LOCATING THE CANNULATION SITE

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Proper site-rotation cannulation technique with

rotation of both venous and arterial needle sites

Venous site-rotation cannulation

sites

Arterial site-rotation cannulation

sites

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Improper site-rotationcannulation technique with

rotation of both venous and arterial needle sites

Poor venous site rotation

Poor arterial site rotation

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“One-site–itis” occurs when

you stick the needle in the

same general area, session

after session

Causes aneurysm and stenosis

formation

“ONE-SITE–ITIS”

Practice of repeatedly puncturing same area,

AKA“one-site–itis”

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Caused by sticking needles in the same general areaAneurysm can also result from stenosis beyond the aneurysm, causing elevated back pressure

AVF ANEURYSM

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Watch the orientation of the needle bevel, and avoid turning your wrist

If the bevel enters sideways, this can cause cutting of the vessel and/or a sidewall infiltration

Use only a back-eye needle for the arterial needleThe venous needle can be back-eye or non–back-eye

NEEDLE INSERTION

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Use of tourniquet should be mandatory

Stabilize vessel

Pull skin taut toward the cannulator

to allow easier needle insertion

(compresses nerve endings,

blocking pain sensation to the brain

for about 20 seconds)

THREE-POINT TECHNIQUE

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“L” TECHNIQUE

Hold thumb and index finger as an “L”

Thumb holds

skin taut over fistula

Index finger stabilizes and engorges fistula

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Rule of Thumb

20–35° angles for fistulae

45° for grafts

ANGLES OF ENTRY

Reality Not every access fits the

rule of thumb; some AV fistulae are very shallow and a

lesser angle can be used You will need to carefully assess the depth of the

access and adjust the angle of cannulation accordingly

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Secure wings Sterile gauze or adhesive bandage over insertion site

Chevron to prevent dislodging Additional tape as needed

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Prep skin prior to cannulation

Stabilize the skin and the AVF

PREPARING FOR CANNULATION

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Use an approximately 20–35° angle of insertion depending on the depth of the access The angle is from the skin to the needle hub First, enter the skin and tissue above the AVF vessel, then the vessel

INSERTION OF NEEDLE

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Once the AVF vessel is entered, the blood flashback is visible in the needle tubingLevel out and advance the needle with very minimal pressure

ADVANCING THE NEEDLE

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Do not “flip” or rotate the bevel of the needle 180°

Flipping can lead to stretching of theneedle-insertion site and cause oozing during the dialysis treatment

PLACEMENT IS CRUCIAL

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Apply gauze dressing without pressureRemove needle at insertion angleApply pressure with 2 fingersDo not use excessive pressure Hold for 10–12 minutes, no peekingUse stethoscope to check for bruit after applying dressing to stick site

NEEDLE REMOVAL

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USE A STETHOSCOPE TO CHECK FOR BRUIT

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Apply adhesive bandages Dispose of needles in biohazard sharps container per guidelines specified in the Occupational Safety and Health Act (OSHA)

NEEDLE REMOVAL

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Pull needle completely from the vein before pushing down on the needle siteHold direct pressure for 10 minutes without “peeking”—no exceptions Do not use clamps unless absolutely necessary!

POST-TREATMENT HEMOSTASIS

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Method in which an individual cannulates the AV fistula in the exact same spot, at the same angle and depth of penetration every time A scar tissue tunnel track develops, allowing for the use of a buttonhole (blunt) fistula needle

BUTTONHOLE TECHNIQUE

Procedure

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May prolong AVF lifespanReduces pain, bleeding, infiltration, infectionVirtually eliminates missed cannulationsPromotes self-care and self-dialysisUse blunt needles, which require no safety device

ADVANTAGES

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Requires same cannulator, same angle, same location Concerns of “one-siteitis”Difficult with fistula covered by:

Heavily scarred skin Large amount of subcutaneous tissue

DISADVANTAGES

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AVF BUTTONHOLE TECHNIQUE

Buttonhole sites

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TWO BUTTONHOLE SITES

Buttonhole sites

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Change blunt needles once the track

is formed

Blunt needles prevent continued cutting of

the buttonhole track and new entry site of the AVF vessel

Blunt needles prevent infiltrations, bleeding from around the

needle sites, and resistance to the needle insertion into the

track and vessel

CHANGING TO BLUNT NEEDLES

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NEEDLES—SHARP AND BLUNT

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A ridge is starting to developA hole is starting to developThis site is not yet ready for a blunt needle

A DEVELOPING BUTTONHOLE

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Needle inserted into the buttonhole tunnel track,but the angle is not aligned with the vessel flap The needle can bounce on the vein and not displace the vessel flap

BUTTONHOLE: WRONG ANGLE OF INSERTION

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Adjust angle to find the flapLift up and down on the needle to readjust the angle until the needle drops into the vessel flap

BUTTONHOLE: ADJUSTED ANGLE OF INSERTION

Causes

BUTTONHOLE: ADJUSTED ANGLE OF INSERTION

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Moving needle from angle used to enter the skin, arm

positioning not in routine place, or patient weight gain

or loss

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It may be possible to speed the development of buttonhole sites by cannulating the sites every dayIt is helpful to switch over to blunt needles as soon as possible

Long-term use of sharp needles will cut adjacent tissues, enlarge the hole, and cause bleeding along the needle path

HELPFUL HINTS…

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If it is impossible to have only 1 cannulator, additional buttonhole sites can be developed at the same time using a second cannulatorIf your patient is hospitalized and the acute hospital renal team does not know how to access a buttonhole, they can:

Rotate sites using standard sharp needles as long as they stay ¾″ away from the buttonhole tracks

ORHave the patient self-cannulate (if the patient has been trained)

MORE HELPFUL HINTS…

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Plan outreach to the acute team and educate regarding buttonhole technique

Continue access monitoring and surveillance, even if patient is dialyzing at home

Inform patients that laminated procedure cards and videos are available

STILL MORE HELPFUL HINTS…

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Bleeding can occur around the needles during dialysis if: You are using sharp needles and have cut the trackThe track has stretched because of trying to direct the needle instead of following the trackYou have made a new track and torn tissue

TROUBLESHOOTING THE BUTTONHOLE

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If, after the weekend, you have trouble with blunt needles, switch to sharp needles for that day, being careful not to cut the track

If a site is not progressing, it is acceptable to abandon that site and find another site

TROUBLESHOOTING THE BUTTONHOLE

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Difficulty re-entering the fistula veinCan occur when transitioning from sharp to blunt needles

The blunt needle “bounces” on the vessel and will not enter the vessel

Corrective action: Change the needle angle slightly until the vessel flap is located and needle drops into the vessel

If it persists, return to sharp needle for a few sessions and then try blunt needle again

TROUBLESHOOTING THE BUTTONHOLE

COMPLICATIONS

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Bleeding during treatment (oozing around needle or infiltration) = fragile vessel wall or back wall penetration; don’t flip the needles

Bleeding post–needle removal = fragile vessel wall or needle trauma or inadequate pressure at puncture sites

Review needle-removal technique. Improper pressure with needle withdrawal = vessel damage

BLEEDING

BLEEDING

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A pattern of prolonged bleeding post–needle removal

may indicate stenosis or clotting disorder. Evaluate bleeding

after 20 minutes

Educate patients about post-treatment hemostasis and what to

do at home should the needle site re-bleed

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INFILTRATION = HEMATOMA

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Don’t flip needleDon’t lift needle in veinFlush with NSS

PREVENT CANNULATION INFILTRATIONS

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Apply gauze without pressureRemove needle at insertion angleApply pressure with 2 fingersHold pressure 10–12 minutes

PREVENT POSTDIALYSIS INFILTRATIONS

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Elevate arm above heartIce 20 minutes on/20 minutes off for 24 hoursWarm compresses after 24 hoursLet fistula restSecond infiltration: Notify vascular access teamDon’t use AVF until directed

TREATING INFILTRATIONS

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If the fistula infiltrates, let it “rest” until the swelling is resolved ( KDOQI Guidelines)If the fistula infiltrates a second time, the RN should notify the vascular access team, including the surgeon, as soon as possible for interventionDon’t use that AVF until further directed

INFILTRATIONS IN NEW AVF

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Check for flashback and aspirateFlush with NSS to ensure the needle flushes with ease and there are no signs or symptoms of infiltrationSaline causes much less damage and discomfort than blood if an infiltration occurs

HOW TO PREVENT INFILTRATIONS

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If bruising or hematoma occurs after dialysis, the surface skin site has sealed but the needle hole in the vessel wall has notUse 2 fingers per site for hemostasisIt is crucial to apply pressure to both the skin and access wall puncture sites

POST-CANNULATION BRUISING AND HEMATOMA

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May be due to location or position of needle(s)May need to change direction of arterial needle If poor flow persists after next session despite changing needle locations, refer to surgeon for evaluation and possible treatment optionsUse tourniquet for cannulation only!

Do not leave in place for entire treatment!!!

POOR FLOW

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Caused by stenosis as vessel narrowing increases “back pressure,” causing vessel distension and weakening of vessel wallMay also be causedor aggravated by frequent cannulations in the same area

ANEURYSM

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Most common complicationCauses:

IV, CVC, linesSurgery to create AVFAneurysms

May be caused by the back pressure associated with stenosis

Needle-stick injury

STENOSIS

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Frequent cause of early fistula failure Juxta-anastomotic stenosis most

common

STENOSIS

Stenosis

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Juxta-anastomotic (most

common stenosis in AVF)

Mid-access

Outflow

Central vessel

TYPES OF STENOSES

Outflow

Central-vein

Mid-access

InflowForearm AVF

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CENTRAL-VEIN STENOSIS

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DISTENDED, OBSTRUCTED LEFT SHOULDER VEINS INDICATIVE OF

CENTRAL-VEIN STENOSIS

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Clotting of the extracorporeal circuit 2 or more times/monthPersistently swollen access extremityChanges in bruit or thrill (ie, becomes pulse-like)Difficult needle placementBlood squirts out during cannulationElevated venous pressures

CLUES TO STENOSIS

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Excessively negative pre-pump APDecreased blood pump speedsInability to achieve BFRChanges in Kt/V and URR RecirculationProlonged postdialysis bleeding Frequent episodes of access thrombosis

CLUES TO STENOSIS

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Surgical/technical problemsPreexisting anatomic lesions (eg, old IV injury)Premature usePoor blood flowHypotensionHypercoagulationFistula compression

THROMBOSIS

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AV fistulas have lowest risk of infection of any vascular access type. However…Each pre- and post-treatment exam should include:

Checking for signs/symptoms of infection, including:Changes of skin over access area

Redness Increase in temperatureSwelling, hardnessDrainage from incision, needle sitesTenderness or pain

INFECTION

INFECTION

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Patient complaints without other indications of Malaise Fever

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PreventionGeneral hygiene

Pretreatment washing of access extremityHand washing, before and after cannulationNo scratching, irritation of skin of access extremity

Precannulation Appropriate skin antisepsisSufficient antiseptic-skin contact time Cannulate while antiseptic is wet or dry, as directed

Cannulation Maintain needle sterilityDo not cannulate through scabs or abraded areas

PREVENTION OF INFECTION

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Steal syndrome is a constellation of symptoms related to ischemia (inadequate blood supply to the hand) caused by the AVF “stealing” blood away from the extremity

Steal causes hypoxia (lack of oxygen) to the tissues of the hand, resulting in severe pain and identified by nail bed discoloration, a cool hand, and a weak or absent pulse

STEAL SYNDROME/ISCHEMIA

STEAL SYNDROME/ISCHEMIA

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Neurological and soft tissue damage to the hand can occur,

resulting in mobility limitations (eg, grip strength, dexterity),

loss of function, ulcerations, necrosis

Steal syndrome/ischemia is estimated to occur in

approximately 5% of vascular access patients, mostly those

with diabetes and peripheral vascular disease (PVD)

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“CLAW HAND” CONTRACTURE FROM STEAL SYNDROME

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Steal symptoms may improve due to the development of collateral circulationProcedures, such as the DRIL (distal revascularization-interval ligation), can successfully treat steal and ischemiaIndividuals who are at high risk for developing acute steal are:

Patients with diabetic neuropathyPatients with PVD

STEAL SYNDROME/ISCHEMIA

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