Renal Replacement Therapy

Question 1

At what GFR may renal replacement therapy be started?

Answer 1

~5-10.

Question 2

What are the acute indications for renal replacement therapy (RRT)?

Answer 2

Acidosis (severe and not responding to treatment)

Electrolyte abnormalities (severe and unresponsive hyperkalaemia)

Intoxication (overdose of certain medications)

Oedema (severe and unresponsive pulmonary oedema)

Uraemia symptoms such as seizures or reduced consciousness

Question 3

What are the indications for long-term dialysis?

Answer 3

End stage renal failure (CKD stage 5) and any of the acute indications continuing long term.

Question 4

What are the options for maintenence dialysis?

Note: while awaiting a transplantation

Answer 4

Haemodialysis (HD)

Peritoneal dialysis (PD)

Question 5

Briefly describe haemodialysis (HD)

Answer 5

Blood is passed over a ‘semi-permeable’ membrane against dialysis fluid in the opposite direction. Diffusion of solutes occurs down the concentration gradient. A hydrostatic gradient is used to clear excess fluid as required (ultrafilration).

Blood filtered by a haemodialysis machine and is accessed via a arterio-venous fistula or tunnelled cuffed catheter.

Question 6

What are the 2 different options for HD?

Answer 6

They need good access to an abundant blood supply. The options for this are:

• Tunnelled cuffed catheter
• Arterio-venous fistula

Question 7

What is the most common regime for HD?

Answer 7

Regimes can vary but a typical regime might be 4 hours a day for 3 days a week.

Daily HD increases the ‘dose’ and improves outcomes.

Home HD should be offered to all suitable patients.