9. Kidney Failure and Dialysis

kidney failure

• patients who have had chronic kidney disease and require kidney replacement therapy

• will die without KRT

options for kidney failure

• haemodialysis

• peritoneal dialysis

• transplantation

• conservative/palliative care

5 year survival at 60yrs after KRT

• transplant→ 75%

• dialysis→ 46%

principle of haemodialysis

• blood pumped out of body where it is passed through dialyser

• tubes have partially permeable membrane→ allows waste products and fluid to pass across it

  • water and waste pass into dialysate→ pumped out of machine

• cleaned blood pumped back into body

central venous catheter

• long tube inserted into large vein

  • jugular, subclavian, femoral

• tip rests just above the hear

• allows blood removal and return for dialysis

arterio-venous fistula

• surgical connection of an artery and a vein in the arm

• preferred choice of access→ lower rate of infection

frequency and options for haemodialysis

• 3x/ week for 3-4 hours

• can be done at haemodialysis centre

  • sense of community

  • travel

• or at home

  • independence

peritoneal dialysis

• dialysis fluid flows from a bag through catheter into peritoneal space

• dialysis fluid absorbs waste and xs fluid from body

• after a few hours, solution and wastes are drained out of belly into empty bag→ discarded

automated peritoneal dialysis

• machine performs exchanges overnight

continuous ambulatory peritoneal dialysis

• manual exchanges 3-4 times a day

• need an appropriate space at home or at work to perform

• 1-3 litres in each exchange

contraindications for peritoneal dialysis

• environment-housing

• complicated abdominal surgery→ adhesions

• incapacity to carry out exchanges

contraindications for haemodialysis

• vascular access issues

• severe haemodynamic instability

haemodialysis advantages

• less protein loss

• shorter treatment times

• social network at dialysis centre

• highly efficient small solute clearances

• no lag time to commence

haemodialysis disadvantages

• hospital based

• scheduled treatments→ shifts

• vascular access problems

• haemodynamic stress

• bleeding risk

• post dialysis-hypotension

• complications→ infections, access failure

peritoneal dialysis advantages

• home based

• increased flexibility

• preservation of residual renal function

• less fluid restriction due to maintenance of residual urine output

• no anti-coagulation

peritoneal dialysis disadvantages

• dedicated space required for storage of equipment and fluid

• membrane failure→ finite lifespan

• hyperglycaemia/glucose load→ disrupts diabetic control

• protein losses

• complications→ hernias, peritonitis, sclerosing peritonitis

conservative management

• medically manage patients with kidney failure

• symptom focused care

• nephrologist or palliative care led

• usually more appropriate for older patients

loop diuretics

• act on ascending limb and loop of Henle

• inhibit uptake of:

  • sodium

  • potassium

  • chloride

  • water

side effects of loop diuretics

• hypovolemia

  • AKI

  • cramps

• hypokalaemia

thiazides

• acts on DCT→ block sodium-chloride cotransporters

• inhibit sodium uptake

• remove sodium and water

side effects of thiazides

• hypovolemia

potassium-sparing diuretics

• spironolactone

• amiloride

spironolactone

inhibits aldosterone→ prevents sodium reabsorption in exchange for potassium

side effects of spironolactone

• hyperkalaemia

• gynaecomastia

amiloride

• inhibits sodium reabsorption in exchange for potassium

• removes sodium and water