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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
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