dialysis - access, hemo dialysis

The History of Dialysis

• Dr. Willem Kolff is considered the father of dialysis. This young Dutch physician constructed the first dialyzer (artificial kidney) in 1943.

• He treated few pts but little success • in 1945 he treated a uremic coma pt after 11

hrs of dialysis and lived for another 7 yrs

Dialysis is a process of removing waste and excess water from the blood to provide an artificial replacement for lost kidney function.

Dialysis works on the principles of the diffusion of solutes and ultrafiltration of fluid across a semi-permeable membrane.

Hemodialysis removes wastes and water by circulating blood outside the body through an external filter, called a dialyzer, that contains a semipermeable membrane.

Mechanisms of Solute Transport

• Diffusion• Osmosis• Reverse Osmosis• Ultrafiltration• Convection

Diffusion

Molecules in solution will spread as evenly as possible in a defined space

Solutes will move down a concentration gradient from an

area of higher concentration to an area of lower concentration

Osmosis

The movement of water through a membrane from a higher to a lower water concentration area.

Osmosis occurs between two solutions separated by a membrane non-permeable to the solutes.

Ultrafiltration

The movement of a fluid across a semi-permeable membrane caused by a pressure gradient.

The pressure gradient can be: A positive pressure ("push") A negative pressure ("suck") or osmosis .

Types of Dialysis

Hemodialysis Peritoneal Dialysis

Peritoneal Dialysis (PD)

PD Exit site and catheter care

• Preparation of patient • Preparation for dialysis • Catheter Exit site care/dressing • Flushing of catheter ( new)

• PET –Peritoneal Equlibrium Test)

HEMODIALYSIS

Vascular Access• Blood can be removed cleaned and returned

to the body at rates between 200 –800ml/mt

• First - an ACCESS must be established

Ideal Vascular Access

An ideal vascular access would provide• Ease of creation• Ready to use when needed• Easy maintenance with repetitive use• Adequate blood flow to deliver prescribed

dialysis dose• Long life without complication of infection and

thrombosis

Access for HD • Blood to be filtered –Access to Blood vessel Artery or Vein 1. Subclavian, internal Jugular and Femoral CATHETERS

2. Arteriovenous (AV) GRAFT for hemodialysis3. Arteriovenous (AV) FISTULA for hemodialysis

Catheters

• Immediate access – double lumen or multi-lumen catheter into SC, internal Jugular or femoral vein

• Risks : hematoma. Pneumothorax, infection, thrombosis of SC vein . Inadequate flow

• Can use for several weeks • Another permanent access created

Arteriovenous (AV) Graft

(Done when pts own vessels are not suitable for fistula – Eg Diabetes)• An arteriovenous (AV) graft is created by connecting a vein to an artery using a soft Synthetic tube.(polytertrafluroethylene (PTFE) • Forearm, upper arm or upper thigh)• After the graft has healed, HD is done by placing two

needles-• one in the arterial side and • one in the venous side of the graft. • The graft allows for increased blood flow.• Grafts tend to need attention and upkeep. • Taking good care of your access may limit problems

AV GRAFT

PTFE Graft

Advantages• Can be needled shortly after formation• Vascular access in patients who might

otherwise require dialysis catheters

Disadvantages• Risk of infection• Thrombosis • Over time may develop “hard to needle” areas

Arteriovenous (AV) Fistula • A fistula is created direct connecting of an artery to a

vein. Once the fistula is created it is a natural part of the body.

• Most preferred access -once the fistula properly matures and gets bigger and stronger; it provides an access with good blood flow that can last for decades

• It can take weeks to months before the fistula matures and is ready to be used for hemodialysis

• Exercises including squeezing a rubber ball to strengthen the fistula before use.

Creating AVF

Criteria for successful AVF formation

Prior to creation

• Arterial diameter 2 -3.5mm Minimum of 2mm advised to decrease risk of

failure• Venous diameter 2.5mm with tourniquet for

AVF

A fistula is the “Gold standard” –because----

It has a lower risk of infection than grafts or catheters• It has a lower tendency to clot than grafts or

catheters• It allows for greater blood flow, increasing the

effectiveness of hemodialysis as well as reducing treatment time

• It stays functional for longer than other access types; in some cases a well-formed fistula can last for decades

• Fistulas are usually less expensive to maintain than synthetic accesses

Fistula care--Cleanliness

• Cleanliness is one way someone on hemodialysis can keep their fistula

uninfected. • Keep an eye out for infections----> pain, tenderness, swelling or redness around the access area

Good needle sticksThe ladder and the buttonhole techniques, .• The ladder technique - “stick” the fistula in a different place along

the length of the fistula every time. • This is called “climbing,” ( it saves from weakening a certain area

by repeatedly sticking it. It also provides time for the puncture site to heal)

• The buttonhole technique. - needle sticks are limited to one site, which is used repeatedly.

• Best for one nurse /self pricking • By going into the access at the same depth and angle — in the

same spot — the access has fewer traumas. • Scar tissue will develop at the stick site making it easier and less

painful to insert the needle. This technique is usually preferred by people who stick themselves

Monitoring …. Post creation, each dialysis throughout the life of the access

• Physical examination ( look, listen, feel) to detect physical signs of dysfunction or loss of patency

• Dialysis clearance ,recirculation and pressures

• Presence of clinical evidence of dysfunction (Difficult cannulation, prolonged bleeding after dialysis, swelling of the extremity, aneurysm formation)

AVF Initial evaluation

• Should be done at 4 weeks after creation to evaluate maturity and development

• Rule of 6’s for maturity– 6mm diameter– 6mm or less in depth– 6cm straight segment for cannulation– 600ml/min blood flow

Routine AV access monitoring Begins with a good history!!!

• Prior central venous catheters, pacemakers , CABG, mastectomy, neck surgery

• Swelling of arm, neck or breast / chest• Prolonged bleeding, extravasation• Frequent clotting• Difficulty with needle placement, aspirating

clots• Presence of dilated collaterals, aneurysms• Clotting risk factors

Aneurysm Risk factors• Over needling of one or more areas

• Fistula age – the longer it has been cannulated the greater the likelihood of an aneurysm developing

• High intra-AVF pressures, i.e. in high flow AVF or where stenosis exists

Collateral veins

Physical Examination

• This is crucial for monitoring Look Listen Feel• Should be done before every use!• Accurate records of the assessment and the

ongoing plan of access management

PULSE - indicator of downstream (ante grade) resistance

• Soft / compressible = Low resistance, no stenosis

• Hard /firm vessel during palpation = High resistance, stenosis present

• (Intensity of the hyper-pulsatile pulse is proportional to the severity of the stenosis)

• ARTERIAL INFLOW (Degree of increased pulse intensity is proportional to arterial inflow pressure. Detects anastomotic stenosis, stenosis of the feeding artery, problem with arterial inflow)

ANASTOMOSIS EXAMINATION• THRILL (indicator of flow) Strong = Good flow Weak = Poor Flow

• Thrill felt during Systole & Diastole (Biphasic) =

Good Flow • Thrill during Systole ONLY = downstream

(antegrade) stenosis = PULSE

Ischemia: Clinical Indicators• Pain and coldness in AVF hand• Necrosis of fingertips• “Steal syndrome” mostly occurs soon after AVF

formation but about 25% of all cases occur months or years post surgery

Stage 4 Steal Syndrome

A. Steal syndrome with painful necrotic ulceration of the middle finger.(B) Stage 4 steal syndrome .(Diabetic ) Simple test – presence of a weak or absent RADIAL pulse which normalises on compression of the fistula

Body of fistula Examination• Palpate entire length of AVF. Compare to other arm/leg• Check for signs and symptoms of infection – redness,

warmth, swelling, ooze, pain, fevers, night sweats (paying close attention to buttonholes)

• New/ increased thrill proximal to anastomosis may indicate stenosis

• Elevate arm. Entire AVF should collapse. Any segment that remains dilated indicates a stenosis proximal to the dilated segment

• Aneurysmal segments. Are they increasing in size? Take photo. Is the skin integrity over the aneurysm compromised?

• Evidence of area needling. Are there other possible cannulation sites? Assess with ultrasound if available

Examination for venous outflow stenosis

Arm elevation test• The AVF should be distended in dependent

position• Upon raising the arm above the head, the

fistula should collapse• Failure to collapse will indicate stenosis in

outflow

Caring for a patient's vascular access for hemodialysis

• Follow your facility's policies and procedures to protect and preserve the vascular access and avoid complications.

• Remove any restrictive clothing or jewelry from the arm.• To prevent injuries, place an armband on the patient or a sign over

the bed that says no BP measurements, venipunctures, or injections on the affected side. When blood flow through the vascular access is reduced, it can clot.

• Perform hand hygiene before you assess or touch the vascular access. If it's a new vascular access with a wound, don gloves. Position the patient's arm so the vascular access is easily visualized.

• Assess for patency at least every 8 hours.

• Palpate the vascular access to feel for a thrill or vibration that indicates arterial and venous blood flow and patency.

• Auscultate the vascular access with a stethoscope to detect a bruit or "swishing" sound that indicates patency. If whistling bruit ? clot – stenosis

• Check the patient's circulation by palpating his pulses distal to the vascular access; observing capillary refill in his fingers; and assessing him for numbness, tingling, altered sensation, coldness, and pallor in the affected extremity.

• Assess access for signs and symptoms of infection such as redness, warmth, tenderness, purulent drainage, open sores, or swelling. Patients with end-stage kidney disease are at increased risk of infection

• After dialysis, assess the vascular access for any bleeding or hemorrhage.

• When you move the patient or help with ambulation, avoid trauma to or excessive pressure on the affected arm.

• Assess for blebs (ballooning or bulging) of the vascular access that may indicate an aneurysm that can rupture and cause hemorrhage.

• Monitor S.Elect, BUN , creatinine, and Hb and HCT levels before and after dialysis.

• Monitor fluid status. Monitor coagulation studies because heparin is used to prevent clotting during dialysis

Miscellaneous

• Hematoma• Seroma• Neuropathy• High output cardiac failure• Infection• Cosmetic issues

Infection

Cosmetic Issues

Preventing Access Complications

• Prevention of infection (hand washing, needling techniques)• Minimize needling trauma• Avoidance of hypotension• Awareness of risk factors for thrombosis• Investigate needling problems• Report change in character of thrill/bruit• Report physical changes in AVF

Thank You Very Much