Vascular Access

Laurie Vinci RN, BSN, CNN September 17, 2011

OBJECTIVES

Discuss vascular access options Describe essential components for

vascular access assessment Discuss vascular access

complications and appropriate interventions

A Patient’s Survival Depends on Proper Functioning of His Lifeline

Vascular Access Options

Arteriovenous Fistula (AVF)- Surgically created connection between an artery and a vein

Arteriovenous Graft (AVG)-Synthetic or biologic material implanted subcutaneously and interposed between an artery and a vein

Tunneled cuffed catheter Non-tunneled, non-cuffed catheter

A-V Fistula First Breakthrough

Initiative (FFBI) Objective: To ensure that people receiving

hemodialysis be given the opportunity to be evaluated for an AVF first

A functional fistula is the goal, not the insertion of a fistula with a poor chance at maturing

In April 2005, the CMS announced that all dialysis units improve AVF prevalence rates to 66% by end of 2009

Diagnostic Evaluation in in Preparation for an Access Preferred method: Duplex ultrasound mapping of

the upper extremity arteries and veins for all patients

To evaluate central veins: 1) Duplex Ultrasound 2) Venography 3) Magnetic Resonance Angiography (MRA)Should be done on patients with pacemakers or prior

catheters NKF KDOQ, 2006, CPG 2

AVF placement in order of priority

A wrist (radiocephalic) primary fistula

An elbow (brachiocehalic) primary fistula

A transposed brachial basilic vein fistula

NKF KDOQI, 2006, CPG 2

Advantages of the AVF

Lowest rate of thrombosis, require the fewest interventions, longer survival of the access

Lower rates of infections than AVG/Catheters Associated with increased survival and lower hospitalization

rates Cost of implantation and access maintenance are the lowest long

term Outflow veins are autogenous tissue which seals and heals after

cannulation. Synthetic grafts only seal by means of a fibrin plug. Can utilize the buttonhole cannulation technique

Disadvantages of the AVF

Vein may fail to enlarge or increase wall thickness Long maturation times: weeks to months following

creation of AVF before they can be used In some, the vein may be more difficult to

cannulate than an AVG Thrombosed AVF may be more difficult in which to

restore flow The enlarged vein may be visible and perceived as

cosmetically unattractive by some individuals Potential for a “steal syndrome” in patients with

compromised peripheral vasculature

Arteriovenous Graft (AVG)

1) Forearm loop graft, preferable to a straight configuration 2) Upper arm graft 3) Chest wall or “necklace” prosthetic graft

or lower extremity fistula or graft (all upper-arm sites

should be exhausted)

Advantages of the AVG

Large surface area for cannulation Technically easier to cannulate than new AVFs ePTFE grafts: No less than 14 days, ideally 3-6

weeks before cannulation to allow healing of incision and resolution of pain and swelling

Placed in many areas of the body Variety of shapes to facilitate cannulation Easier for surgeon to handle, implant, and

construct the vascular anastomoses

Disadvantages of the AVG

Increased incidence of thrombosis and infection over an AVF

Patients have a higher mortality risk than those dialyzed with an AVF

Shorter patency rates than an AVF Cannulation sites seal but do not heal Potential for allergic response May cause “steal syndrome” if

compromised peripheral vasculature

Assessment of AVF or AVG Assess access vessel: 1) Redness, bruising, hematoma, rash

or break in skin, bleeding, exudate, atypical warmth, tenderness/pain, aneurysm or pseudoaneurysm

2) Maturation of the vessel, direction and characteristics of the flow (thrill), auscultate for bruit noting changes in pitch

3) Identify cannulation patterns: rotation of site, presence of buttonholes

Cannulation of AVF and AVG Confirm direction of blood flow Select sites away from recent entries Arterial needle (pull) can be against the flow

(retrograde) or with the flow (antegrade) Venous needle (return) always with the flow

and above the arterial needle Never cannulate into anastomoses,

aneurysms, or pseudoaneurysms

USE ASEPTIC TECHNIQUE

Cannulation AVF and AVG

For AVG cannulation: Angle of needle insertion is approximately 45 degrees. First cannulation can be 2 weeks post-op for most grafts using needles of the standard size.

For AVF cannulation: Always use a tourniquet. Angle of insertion is approximately 25 degrees. Rotate sites using ROPE LADDER TECHNIQUE or buttonhole cannulation

First cannulation of newly matured AVF: if functioning catheter, use a #17 ga. needle for arterial pull and venous return via catheter.

Do not “flip” needles. This risks cutting or coring the endothelium of the vessel

Post dialysis AVF/AVG Care

Remove needles at same angle as entry, use needle safety device and discard into sharps container immediatelyCompress with 2 fingers following complete removal of the needle to prevent pain and damage to the vesselOptimal to remove one needle at a time. Clamps should be used only if there is no alternative (one site at a time)Do not occlude blood flow in peripheral access, check thrill distal to site of pressureSites can be dressed with adhesive bandage, guaze, and tape but should never be circumferential nor tight

AVF: INFECTION/INTERVENTIONS

Rare, but most often occur at cannulation site

Should be treated as a subacute bacterial endocarditis with 6 weeks of antibiotic therapyAvoid cannulation at the infected site and rest armTake blood/wound cultures, then initiate antibiotic therapy with broad spectrum Vancomycin plus an aminoglycosideConvert to appropriate antibiotic upon culture resultsFistula surgical excision in cases of septic emboli NKF KDOQI, 2006, CPG 5

INFILTRATION: AVF/AVG INTERVENTIONS

Pain and swelling (hematoma) at time of cannulation or during the dialysis treatment. On dialysis: low arterial pressure alarm may indicate arterial needle infiltration, high venous pressure alarm may indicate venous needle infiltration At time of cannulation: remove needle, hold firm pressure until bleeding stops and apply ice. If hematoma is large, ice pack x 15 mins. before trying site again. If venous needle, cannulate above site to avoid feeding into infiltrated area.On dialysis: blood pump off, insert another needle, leave original needle in place unless hematoma enlarges, apply ice to area of infiltrationInstruct patient on application of ice intermittently for first 24 hrs., then warm compresses

AVF/AVG STENOSIS

Findings indicative of a stenosis:Decreased flows, increased pressures, arm edemaCentral vessel stenosis: breast, neck, chest, face swellingAppearance of collateral veinsAVF does not collapsed with arm elevation Increase in post dialysis bleeding timeDifficulty with cannulationPain Altered characteristic of thrill or bruitRecent pseudoaneurysm formation in AVG

AVF/AVG STENOSIS

Underdialysis can be minimized or avoided and the rate of thrombosis reduced via access monitoring and surveillance for vascular access stenosis

Interventions Doppler ultrasound or Fistulogram to measure flow and detect stenosis Treatment for hemodynamically significant stenosis (> 50%) is balloon

angioplasty. Stenting is sometimes warranted. Follow-up fistulograms may be scheduled.

Depending on fistulogram findings, surgical revision may be necessary Venous hypertension: arm elevation above level of heart

bnormal physical exam >50% stenosis

Nontunneled, Noncuffed Acute Catheters Can be inserted at the bedside, only in

hospitalized patients and used for no more than one week

Catheter tips should be in the superior vena cava (SVC); confirmed by CXR or fluoroscopy at time of placement

Uncuffed femerol catheter should only be used in bed-bound patients , left in place for no more than 5 days. Highest infection rates

NKF KDOQI, 2006,CPG 2

Tunneled, Cuffed Catheters

Long term use only in patients: 1) not suitable for AVF or AVG 2) has AVF or AVG planned 3) AVG or AVG waiting to mature 4) waiting for scheduled live donor transplant Preferred site is right internal jugular vein: more

direct route to right atrium and lower risk of complication compared to other sites

Other options: Rt. External jugular, Lt. internal and external jugular veins, subclavien veins, femerol veins, translumbar and transhepatic access to IVC

Should not be placed on same side as maturing AV access

Tunneled, Cuffed Catheters

Ultrasound guidance and fluoroscopy used for placement of the catheter

Tip of the catheter should be in right mid-atrium

Fibrous cuff, about 1 cm from exit site inside tunnel; designed to create a barrier to organism entry and prevent catheter dislodgement

Advantages of Tunneled, Cuffed Catheters

Can be inserted into multiple sites relatively easy

No maturation time, can be used immediately

Cause no changes in cardiac output or myocardial load

Provides access for months permitting AVF maturation

Disadvantages of Tunneled Cuffed Catheters

High morbidity due to thrombosis and infection

Risk of central venous stenosis or occlusion Frequent episodes of occluded catheters due

to thrombosis or fibrin sheaths: 1) lytic agent or interventional procedure 2) leads to reduced dialysis adequacy associated with increased morbidity and mortality

Catheter Assessment

Absence of: 1) Facial/neck edema, respiratory distress,

cardiac arrhythmia 2) Catheter occlusion: inability to withdraw

anticoagulant and blood 3) Fibrin sheath with tail blocking the tip

holes: ability to push saline but inability to pull 4) Integrity of the catheter, well healed exit

site: absence of redness, swelling, discoloration, drainage, bleeding or catheter migration such as a visible cuff

INFILTRATION: AVF/AVG INTERVENTIONS

If new access and patient has a catheter access, do not recannulate till swelling has receded

If unable to clearly feel or see the vessel, the patient has no catheter and needs dialysis: consider use of short-term catheter

REMEMBER TO MAINTAIN VISIBILITY OF THE ACCESS AND CONNECTIONS AT ALL TIMES

CATHETER (CVC) DYSFUNCTION

Dysfunction defined as failure to attain and maintain blood flow rate of 300ml/min or greater at a prepump arterial pressure less than -250 mmHg. Signs of CVC dysfunction: low arterial pressure alarms and high venous pressure readings (greater then 250 mmHg) limiting blood flow rates which are not responsive to patient repositioning or catheter flushing, unable to aspirate blood freelyCauses: Mechanical (kinks or dislodgement), misplaced sutures, catheter migration, drug precipitation, patient position, catheter integrity, holes/cracks, partial or complete occlusion due to a thrombus or fibrin sheath

NKF KDOQI, 2006, CPG 7

CATHETER (CVC) DYSFUNCTION INTERVENTIONS

Check for and correct mechanical obstruction such as kinking of catheter, lines or clamp indentation

Check for dislodgement evidenced by cuff extrusion Tape in place and report to vascular team

Reposition the patient: supine returns the patient to the position when the catheter was inserted, may reposition tip of catheter in Rt. atrium. Central veins also maximally engorged in this position. Change position of the head or have the patient cough

CATHETER (CVC) DYFUNCTION INTERVENTIONS

Flush each lumen with 10 ml of normal saline Reverse lines using aseptic technique If flow problem persists, likely thrombus in lumens,

on the wall of the vessel or a fibrin sheath. Use thrombolytic agent per MD order

May need to change the catheterAll catheters “locked” with some anticoagulant

to prevent thrombus. Firmly infuse to the volume of the lumens, then quickly reclamp lumen to prevent negative pressure in catheter pulling blood in the side holes.