end stage renal failure and renal replacement therapy Flashcards
2 renal replacement therapy modalities
- dialysis
- kidney transplantation
what are the 2 types of dialysis
- haemodialysis
- peritoneal dilaysis
what is the chronic kidney disease classification (5)
stage 1 - kidney damage with normal or increased GFR (>90)
stage 2 - kidney damage with mildly reduced GFR (60-80)
stage 3 - moderately reduced GFR (30-59)
stage 4 - severely reduced GFR (15-29)
stage 5 - kidney failure (<15 or dialysis)
should pts with eGFR >60 be considered to have CKD
not unless they have:
1. urinary abnormalities (proteinuria, haematuria etc.)
2. structural abnormalities
3. genetic disease
4. histologically established disease
causes of CKD (8)
- T2DM
- HTN
- glomerular disease
- idiopathic
- T1DM
- cystic/hereditary
- nephiritis
- tumours
what are ppl w CKD more likely to die from
cardiovascular disease (2-4x higher risk) -> more likley to die form CD before they progress to renal failure
both reduced eGFR and proetinuria are independently and additively associated with adverse CV outcomes
examples of presentation of chronic kidney disease (6)
very wide range of symptoms, examples of some are:
1. fluid overload
2. uremia (retention of uric toxicns)
3. acidemia
4. anemia (CKD 4)
5. mineral bone disease
6. hypertension
how can sodium retention and volume overload be treated in CKD
sodium restriction diuretics
how can hyperkalemia be treated in CKD
- dietry restriction
- avoid NSAIDs
how can metabolic acidosis be treated in CKD
NaHCO3
how can abnormal Ca/PO4 balance be treated in CKD
- phosphate binders (reduce hyperphosphantemia)
- calcimimetics (hypocalcaemia)
how can anaemia be treated in CKD
- erythropoeises stimulating agents
- iron replacement
what is the aim of renal replacement therapy
replaces normal blood-filtering functions of the kidney
what is haemodyalisis
ongoing dialysis that takes place at a dialysis centre 3-5x a week
explain the process of haemodyalisis (4)
- blood is exposed to dialysate acriss semi-permiable membrane
- Small molecules(urea, creatinine) and electrolytes pass through pores in membrane, large molecules(albumin, Ig’s) and blood cells do not
- Concentration differences across the membrane allow molecules to diffuse down a gradient
- Waste products are removed and desirable molecules replaced
what is required for haemodialysis (5)
- Dialysis membrane- biocompatible membrane with adequate surface area/permeability for solute clearance and ultrafiltration;
- Dialysate- fluid containing physiological electrolytes concentration of sufficient purity;
- Effective control and safety mechanisms- pumps for blood and dialysate flow, transmembrane pressure, temperature, detection of blood/air leaks;
- Vascular access
- Anticoagulation
in haemodialysis, how is water driven through the membrane and how is water removal controlled
- driven through by hydrostatic forces (high pressure in blood, low in dialysis fluid) -> ultrafiltration
- varying the pressure gradient across the membrane controls water removal
what is the dialyser
the “artifical kidney” -> different SAs available depending on the size of the pt
what is haemodiafiltration
combination of diffusion and convection to enhance the clearance of middle molecules -> removal of higher molecular weight uraemic toxins, greater haemodynamic stability and reduces erythropoiesis-stimulating agents (ESAs) requirements
2 types of haemodialysis access
- filstula - optimal form of vascular access, surgical anastomosis of artery and vein required
- tunnelled line - frail, elderly pts or those who cannot have fistula
what arteries/veins are used in fistula haemodialysis access (3)
start distally in non-dominant arm
1. radial artery + cephalic vein
2. brachial artery + cephalic vein
3. brachial artery + basilic vein
from which end of the fistula is blood taken from and to where is it returned
taken from distal end of vein, returned to proximal end
why is a fistula preferred over a tunnelled line of dialysis access
tunnelled line is more prone to infection
can haemodyalisis be done at home
yes - patient can perform nocturnal, daily dialysis
-> majority done in hospital as pts have to learn a lot about dialysis, they are responsible for their own care and must pass the training
