Renal Replacement Therapy

Question 1

What are the 3 main functions of the Kidney?

Answer 1

Toxin removal
Fluid removal
Hormone production

Question 2

How do we measure kidney function?

Answer 2

GFR
Volume of glomerular filtrate formed in al nephrons of both kidneys per min
Estimated via Cr

Question 3

How do we assess CKD?

Answer 3

Estimated GFR

Stage 1 - >90
Stage 2 - 89-60
Stage 3a - 59-45
Stage 3b - 44-30
Stage 4 - 29-15
Stage 5 - >15

Question 4

What stages of CKS are worrying?

Answer 4

4 & 5
5 defines kidney failure and requires renal replacement therapy
3 is common and not that concerning in elderly

Question 5

What are the different forms of Renal replacement therapy?

Answer 5

Transplant (Live&Deceased)
Conservative care
Peritoneal dialysis
Haemodialysis

Question 6

What is the best form of RRT?

Answer 6

Best form of renal replacement therapy is a pre-emptive live donor renal transplant

Before dialysis

Question 7

What are the advantages of transplantation?

Answer 7

Approximates closest effect of native kidneys
Cheaper over time
Saves £25,000/yr/pr

Question 8

Who is eligible for transplantation?

Answer 8

GFR < 15

GFR > 15 and likely to need RRT in less than 6 months

Question 9

What are contraindications of transplantation?

Answer 9

Untreated malignancy
Active infection
Untreated HIV
Life expectancy < 2 years

Question 10

What are the main features of live donation?

Answer 10

Graft survival: 20-25 years
Average waiting time: 3-6 months
Planned daytime surgery
Low risk from donor

Question 11

What are the main features of deceased donors?

Answer 11

Graft survival: 15-20 years
Average waiting time: 2-4 years
Unplanned surgery
Cannot be sure of full medical history/previous kidney function

Question 12

How are kidney’s matched?

Answer 12

HLA matching
Does not need to be perfect
1-1-1 is acceptable

Cross match is more important

Question 13

What is the Kidney sharing scheme?

Answer 13

Scheme for blood group incompatible or HLA incompatible donors

Question 14

What is peritoneal dialysis?

Answer 14

Utilises peritoneum as dialysis membrane

1. Continuous ambulatory peritoneal dialysis (0.5 hours a few times a day)
2. Automated peritoneal dialysis
   (a few short exchanges overnight)

20%

Question 15

What are the advantages of peritoneal dialysis?

Answer 15

Easy to travel
Low technology
Flexibility

Question 16

What are the disadvantages of peritoneal dialysis?

Answer 16

Needs to be continuous therapy

Peritonitis risk

Question 17

What is haemodialysis?

Answer 17

Uses extracorporeal circuit
Usually 3-4 hours, 3x a week
Predominantly in-centre
Uses counter current exchanger with dialysate fluid

Question 18

When should dialysis be started in CKD?

Answer 18

GFR < 8
Uraemic symptoms
- Weight loss
- Anorexia
- Fatigue
Fluid overload refractory to diuretics