RRT

Question 1

Indications

Answer 1

Suggested to start when GFR<15ml/min + symptoms
Psychological preparation necessary
PD vs. HD depends on med, social and psych factors

Question 2

General dialysis complications

Answer 2

20% annual mortality
  Cardiovascular disease
  Malnutrition
  Infection
  uraemia → granulocyte dysfunction → ↑ sepsis- related mortality
  Amyloidosis
  β2-microglobulin accumulation   Carpal tunnel, arthralgia
  Renal cysts → RCC

Question 3

Mechanism of haemodialysis

2

Answer 3

Counter current flow

Ultreafiltration

Question 4

What is counter current flow

Answer 4

Blood flows on one side of semipermeable membrane
Dialysate flows in the opposite direction on the other
side.
Solute transfer by diffusion

Question 5

What is ultrafiltration

Answer 5

Fluid removal by creation of –ve transmembrane pressure by decreasing the hydrostatic pressure of the dialysate.

Question 6

Complications of haemodialysis

Answer 6

Disequilibration syndrome (usually only 1st dialysis)
Rapid changes in plasma osmolarity → cerebral oedema
n/v, headache and ↓GCS
Fluid balance: BP↓, pulmonary oedema
Electrolyte imbalance
Aluminium toxicity (in dialysate) → dementia
Psychological factors

Question 7

What is haemofiltration

Answer 7

Usually only used in ITU
Takes longer cf. HD but there is less haemodynamic
instability.

Question 8

Mechanism of haemofiltration

Answer 8

Use a Vas Cath
Blood filtered across a highly permeable membrane by
hydrostatic pressure and water and solutes are removed
by convection.
Ultrafiltrate is replaced by isotonic replacement.

Question 9

Mechanism of peritoneal dialysis

Answer 9

Dialysate introduced into peritoneal cavity by Tenchkhoff catheter.
Uraemic solutes diffuse into fluid across peritoneum Ultrafiltration: addition of osmotic agent (e.g. glucose) ~3L 4x /day ̄c ~4h dwell times

Question 10

Types of peritoneal dialysis

Answer 10

CAPD: fluid exchange during day ̄c long dwell @ night
APD: fluid exchanged during night by machine ̄c long
dwell throughout day.

Question 11

Advantages of PD

Answer 11

Simple to perform
Requires less equipment
Easier @ home or on holiday
Less haemodynamic instability useful if cardio disease

Question 12

Disadvantages of PD

Answer 12

Inconvenience
Body image
Anorexia

Question 13

Complications of PD

Answer 13

Peritonitis
  Exit site infection
  Catheter malfunction
  Obesity (glucose in dialysate)
  Mechanical: hernias and back pain