Glomerular Filtration rate and its determinants.pptx
DIALYSIS - Access, Hemo dialysis
1.
2. 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
3. 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.
4. Mechanisms of Solute Transport
• Diffusion
• Osmosis
• Reverse Osmosis
• Ultrafiltration
• Convection
5. 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
6. 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.
7. 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 .
12. 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)
14. Vascular Access
• Blood can be removed cleaned and returned
to the body at rates between
200 –800ml/mt
• First -
an ACCESS must be established
15. 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
16. 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 hemodialysis
3. Arteriovenous (AV) FISTULA for hemodialysis
17. 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
18. 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
20. 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
21. 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.
23. 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
24. 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
25. 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
26. Good needle sticks
The 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
27. 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)
28. 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
29. 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
30. 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
32. 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
33. 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)
34. 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
35. 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
36. 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
37. 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
38. 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
39. 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.
40. • 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
41. • 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