2. RRT: a brief history
• 1861 Term ‘ dialysis ’ first coined
• 1923 First human PD (Peritoneal Dialysis )
• 1924 First human HD (Hemodialysis)
• 1946 PD used to treat ARF
• 1947 First cadaveric kidney transplant.
• 1948 HD used to treat ARF in the Korean war
3.
4. Early 1950s Cadaveric transplants for CRF ; no
immunosuppression — all rejected within 6
months.
• 1954 First successful monozygotic twin transplant
• 1959 Non-monozygotic twin transplant (with Whole
body irradiation as immunosuppression)
• 1960 First long-term HD patients (Seattle, USA)
• 1966 Forearm AVF developed
• 2013 First successful rodent transplantation of a
bioengineered kidney
5. TYPES OF RENAL RT
• HEMODIALYSIS :-eg. 1)Continuous renal
replacement therapies (CRRTs)
2)Slow low-efficiency dialysis (SLED) 6–12 h
per session.
Both specific to the management of acute
renal failure. 3) Intermittent hemodialysis 3-4
hr /session
• PERITONEAL DIALYSIS
• RENAL TRANPLANTATION
6. Indications for RRT IN CKD
• SEVERE METABOLIC ACIDOSIS
• HYPERKALEMIA
• PERICARDITIS
• URAEMIC ENCEPHALOPATHY
• INTRACTABLE VOLUME OVERLOAD
• INTRACTABLE GI SYMTOMS IN CKD PTS
• ASYMPTOMTIC Pts, WITH GFR OF 5-9ml/min/
1.73 m2 or below 10ml/min/1.73m2
7. Indications for RRT in AKI
• VOL EXPANSION THAT CANNOT BE MANAGED
WITH DIURETICS.
• HYPERKALEMIA REFRACTORY TO MEDICAL
THERAPY
• CORRECTION OF SEVERE ACID BASE
DISTURBANCES THAT ARE REFRACTORY TO
MEDICAL THERAPY
• SEVERE AZOTEMIA (BUN >80- 100 )
• UREMIA
8. Dialysis: an introduction
Normal functioning kidneys:
• Remove excess salt, water, and acid.
• Remove or regulate other electrolytes (e.g. K + ,
Ca 2+ , Mg 2+ , PO 4 ).
• Remove waste products of metabolism (Ur and
Cr are measured routinely, but there are many
others).
• Make erythropoietin.
• 1 A -hydroxylate (and hence activate) vitamin D.
9. • Dialysis acts as surrogate for all but the last two
of these (which can be achieved
pharmacologically).
• Transplantation more completely (but still
partially) replaces normal kidney function and
should be regarded as the optimum treatment of
ESRD.
• Median survival for patients starting RRT in the
age group 45–54 is currently 10.5 years,
for age 55–64 it is 5.6 years and for
age 65–74, 3 years.
11. Haemodialysis (HD)
• During dialysis, blood is exposed to dialysate
(with physiological concentrations of electrolytes)
across a semi permeable membrane.
• Small molecules such as Ur (MW 60Da), Cr
(MW113Da) and electrolytes pass through pores
in the membrane.
• Large molecules such as albumin (MW 60,000Da),
IgG (MW 140,000Da) and blood cells do not
12. • Concentration differences across the membrane
allow molecules to Diffuse down a gradient.
• Waste products, Removed
• Desirable molecules or ions (e.g. HCO 3 – ) are
Replaced.
• Water can be driven through the membrane by
hydrostatic force (ultrafiltration, UF).
• In addition to a means to remove water, UF can
also be used as a means of solute clearance by
Convection.
13. What is required for haemodialysis?
• Dialysis membrane :- a biocompatible
membrane with adequate surface
area/permeability for solute clearance and
ultrafiltration.
• Dialysate : of sufficient purity and containing
the required concentration of electrolytes.
• Effective control and safety mechanisms
14. • Vascular access
1.AVF fistula: optimal form of vascular access
2. PTFE (poly-tetra-fluoro-ethylene graft: second best
3.Tunnelled, cuffed central venous catheter: ideally not
long term .
4. Temporary central venous catheter: for immediate
use; e.g. in AKI.
• Anticoagulation
15. Haemodialysis
• Solute clearance by diffusion
(mainly).
• Dialysate is required.
• Diffusion is maximized by
maintaining high-fl ow rates of
blood and dialysate and by
pumping the two through the
dialyser in countercurrent
directions.
• • Larger MW (>20kDa) molecules
are generally poorly removed.
• • Usually administered
intermittently (e.g. 4h, 3x/week).
Haemofiltration
• Solute clearance by convection
(mainly).
• No dialysate required.
• Large volumes need to be filtered
to achieve adequate solute
clearance.
• This would cause hypovolaemia
unless replacement fluid
administered (usually pre-
prepared 5 – 10L bags).
• Removes larger MW (30 – 50kDa)
molecules (e.g. vitamin B12 and
B2 microglobulin) more effi
ciently than dialysis.
• Continuous (24h) HF is associated
with greater haemodynamic
stability and often favoured for
RRT in a critical care setting
17. Dialysate
• Ultrapure water :- A solution of ultrapure
water, Na + (132 – 150mmol/L), K +
(usually 1.0 – 3.0mmol/L), Ca 2+ (1.0 –
1.25mmol/L), Mg 2+ , Cl – , dextrose, and
buffer.
18. Dialysers and membranes
• Dialysis membranes are not inert. They can
activate complement and inflammatory cascades
(short- and long-term complications)
• Biocompatible membrane :- elicits the minimum
inflammatory response.
• Cellulose membranes (e.g. Cuprophan ® ) :- least
biocompatible
• Modified cellulose (e.g. Hemophan ® ) :-More
biocompatible.
• Synthetic membranes (e.g. Polysulfone ® ,
polyamide, polyacrylnitrile) :-More recently
developed. Most biocompatible.
19. Dialysis prescription and adequacy
• Dialysis can be considered adequate if it
provides relief of uraemic symptoms and
controls acidosis, fluid balance, and serum K +
• It should also allow a feeling of physical and
psychological well-being.
20. Pre and Post dialysis Investigations
1. Body weight
2. BP
3. CBC (HB , HCT)
4. KFT
5. BUN
6. ECG
7. ABG
8. VIRAL MARKERS (HHH)
9. SERUM ELECTROLYTES
10. COAGULATION PROFILE
21. Aspects of dialysis adequacy
• Solute clearance .:-Aim to achieve a target Kt/V of
>1.2 (k=dialyser clearance of urea , t= dialysis
time , v = vol of distribution of urea )or URR >65%
(urea reduction ratio)
• Blood pressure and fluid balance:-high BP in a
dialysis patient should be treated by reducing ‘
dry weight ’ (i.e. post-dialysis weight).
This should be the weight at which salt and water
balance is optimal.
22. Oligo-anuric patients (majority of long-term
HD patients) :-restrict their interdialytic salt
and fluid intake in order to achieve this aiming
for weight gains of 1 – 2.5kg (maximum)
between sessions.
Pre- and post- dialysis BP <140/90mmHg is
desirable. Preferably be achieved without anti-
hypertensive medication. Inter- or intra-
dialytic hypotension should be avoided.
23. • Nutrition:- A low pre-dialysis Urea may reflect
poor nutrition, rather than good dialysis !!
Targets:
-Serum albumin >35g/L.
-Normalized protein catabolic rate (nPCR)
>1.0g/kg/day
-Acceptable anthropometric measures.
24. • Clearance of other molecules: ‘ Middle ’
molecule clearance thought to be important
to prevent the long-term complications of
dialysis. B 2 microglobulin is the most used
marker.
Phosphate clearance is also important and
appears to correlate more with hours of
dialysis than rate of small molecule clearance
• Quality of life and life expectancy
25. • Most guidelines suggest monthly
measurement of Kt/V. Online methods of
measuring Kt/V are provided on modern
dialysis machines (often using Na + clearance
to estimate urea clearance).
• HD adequacy is multifaceted. Achieving a
desired Kt/V does not necessarily equate to
optimal dialysis.
26. Management of dialysis patients on
non-renal wards
• Inform your renal team at the pre assessment
stage
• DO NOT routinely administer IV fluids (unless the
patient is haemodynamically compromised—if
so, use small boluses, assess volume status
regularly and call for expert help)
• DO NOT give K+ supplementation
• DO NOT place a urinary catheter unless there is a
clear urological indication. Oligo-anuria is
virtually universal in this patient group!
27. • If the patient is clinically overloaded as the
patient may require urgent dialysis.
• If K+ >5.5 mmol/L inform renal team.
• For new medication, check whether the drug
is safe in ESRD and if a dose adjustment is
required. Be particularly cautious with opiate
analgesia and sedatives (accumulation!)
• Check (and document) daily weight.
28. • Does the patient have an AVF? NEVER insert
an IV cannula into a fistula arm.
• The back of the hand on the non-fistula arm is
the best site.
• Dialysis central venous catheter (CVC), should
not be used for anything else but HD
29. Anticoagulation
• Extrinsic coagulation cascade!
• Unfractionated heparin:-
• Indirect thrombin inhibitor.
• Metabolized in the liver and by vascular
endothelial heparinases
• Short half-life and fully reversible with
protamine.
30. Low molecular weight heparin
• Inhibit factor Xa
• Predominantly renally cleared ∴ increased half-life
in ESRD
• Bleeding:-
Patients with ESRD have an increased incidence
rate of major bleeding.
Caution while prescribing aspirin and warfarin etc
in ESRD pts
31. Dialysis access: AVF/PTFE
• ~25% of all admissions in the dialysis
population relate to access failure and remain
an important source of morbidity and
mortality.
• Reliable vascular access is the cornerstone of
HD therapy.
32. AV fistula
• Surgical anastomosis of an artery and a vein
(under LA or GA)
• wrist (radiocephalic) or elbow
(brachiocephalic, brachiobasilic)
• Maturation for 6 – 8 weeks (minimum) is
required prior to needling
33.
34. Fistula care: what every doctor and
patient should know
• Needling should only be carried out by a trained operator
(usually a dialysis nurse).
• Technique: avoid using the same site repetitively (false
aneurysm formation).
• Never put a tourniquet or BP cuff on a fistula arm.
• Do not use a fistula to take blood.
• Hypotension (and volume depletion) increase thrombosis
risk.
• A clotted fistula or graft requires immediate attention (time
to declotting is a major determinant of success).
• No thrill or buzz in fistula = thrombosis (ensure patients are
aware of this)
35.
36. Haemodialysis access: lines
• Temporary dialysis catheter:- For immediate
use;-
Ideally leave in situ for ≤2 weeks (femoral <5
days)
• Tunnelled (and cuffed) dialysis catheter:-
A dual-lumen (or two single-lumen) venous
catheter .
Immediate use and usually left in situ for 1 – 3
months (occasionally longer).
37.
38. Fluid balance on dialysis
• HD patients should gain no more than 2% of
their body weight in fluid between sessions
(1.4kg in a 70kg adult).
• Gains of >4% (2.8kg in a 70kg adult) are
described as large interdialytic weight gains
39. Dry weight (DW)
• It is the end-dialysis weight thought to best
represent a euvolaemic state.
• It is the body weight in kg against which the
ultrafiltration volume is set at each session.
For example:
• HD patient with a dry weight of 70kg.
• Pre-dialysis weight 72.7kg.
• Target UF volume = 2,700mL over 4h to achieve
DW
40. Assessing DW
• There are number of ways but should always
include clinical assessment.
• Examination:- BP, JVP, ankle oedema
• Fluid gains between dialysis sessions.
• Continuous blood volume monitoring
41. Sodium and Dialysis
• Dietary salt intake is a vital part of
haemodialysis patients ’ salt balance !
• Achieving <100mmol/day intake (equivalent
to 6g NaCl) is difficult.
42. Intradialytic hypotension
• IDH is defined as a fall in SBP >20mmHg (or
MAP >10), associated with symptoms, or a fall
to SBP <100mmHg.
• Symptoms are :- Cramps, abdominal pain, or
nausea (reduced gut perfusion).
• Yawning, sighing, anxiety, or dizziness
(reduced cerebral perfusion).
• Chest pain or arrhythmias.
43. • IDH is Always related to the rate of ultrafi
ltration (i.e. the speed of fluid removal)
• It is less usual at UF rate <0.3mL/min/kg and
• Common if UF rate >0.6mL/min/kg.
44. Immediate management of IDH:
• Stop ultrafiltration (UF).
• Place patient in Trendelenburg position.
• Administer 0.9% NaCl as a 250mL bolus.
• Recheck BP.
• Undertake thorough clinical review (including
medications) to prevent
• future episodes!
45. Management: preventing IDH
• Maintain residual renal function where possible.
• Confirm cardiac function (ECG, echo)
• Dietary salt and fluid intake advice
• Stop dialysis-day antihypertensives (but try to
continue B -blockers if prescribed).
• Correct anaemia
• Increase dialysis hours or increase number of
weekly sessions
• Cooled dialysate reduces IDH and prevents
RWMAs.
46. Extended hours HD treatments
• For >3 decades in Tassin, France, patients with
ESRD have received 8h in-centre dialysis
sessions 3x/wk.
This regime is amongst the best in the world.
Modern dialysis care should focus on: -
- increased dialysis frequency
- increased dialysis duration
- Or both of these.
47. Other HD complications
• Acute complications
1 Cramps:- Associated with lowBP, low Na+,
hypovolaemia and hypoxia.
2 Nausea and vomiting
3 Headache
4 Fever
5 Haemolysis : Rare but serious .
6 Clotting of extracorporeal circuit (blood lines and
dialyser)
48. 7 Chest pain:- Assume cardiac in origin until
proven otherwise.
8 Cardiac arrest in the dialysis unit: Consider
hyperK+ and other electrolyte imbalances.
9 Disequilibrium:- due to high blood urea levels
being reduced too rapidly.
10 First use syndrome/dialyser reaction:-
anaphylaxis or milder delayed reactions.
11 Accidental disconnection
12 Air embolism
49. 13 Blood leak
14 Hard water syndrome:- failure of the reverse
osmosis (RO) machine or the water softening
plant.
• LONG TERM COMPLICATIONS
1 Cardiovascular Disease
2 Vascular Calcification
3 Malnutrition
4 Aluminium toxicity
5 Dialysis related amyloidosis
50.
51. Indications for Peritoneal Dialysis
• Vascular access failure
• Intolerance to Hemodialysis
• Congestive heart failure
• Prosthetic valvular disease.
• Children aged 0 to 5 years
• Patient preference
• Distance from hemodialysis centre.
• Poor cardiac function
52. HEMODIALYSIS
• Requires vascular access
devise (temporary or
permanent )
• Requires a complex
specialised dialyzer
• Require a skilled
hemodialyis nurse.
• Intermittent ( q3-4 days)
• Preffered in ESRD .
• Slower
PERITONEAL DIALYSIS
• Req insertion of catheter in
peritoneal cavity.
• Doesn’t req a specialised
dialyser .
• Can be done by patient
(sterile technique ).
• Continous (4-6 hrs q 24 hrs )
• Have few cardio side effects ,
can be used in unstable
patients
• Faster
• Better quality of life and
maintains residual renal
function
