Renal Support

• Acute kidney injury (renal failure) requiring dialysis is a common reason for admission to the intensive care unit and a common complication seen in patients in ICU for other conditions
• Acute kidney injury is a life-threatening condition with high mortality
• Dialysis is a method for performing the filtration tasks of the kidneys artificially. It involves removing excess fluid, solutes and waste products
• Indications for Acute Dialysis

  • Acidosis (severe and not responding to treatment)
  • Electrolyte abnormalities (treatment-resistant hyperkalaemia)
  • Intoxication (overdose of certain medications)
  • Oedema (severe and unresponsive pulmonary oedema)
  • Uraemia symptoms such as seizures or reduced consciousness
• The mnemonic AEIOU can be used to remember the indications for acute dialysis in patients with severe acute kidney injury
• Options for dialysis in patients with renal failure

  • Peritoneal dialysis (rarely used in acute renal failure)
  • Haemodialysis
• Peritoneal dialysis is very rarely used in acute kidney injury and is generally limited to
• Raemia symptoms


  • Seizures
  • Reduced consciousness
• Options for dialysis in patients with renal failure

  • Peritoneal dialysis
  • Haemodialysis
• Peritoneal dialysis is very rarely used in acute kidney injury and is generally limited to use in patients with chronic kidney disease
• Haemodialysis


  1. Blood is taken out of the body, through the dialysis machine, then pumped back into the body

  2. Blood passes along a series of semipermeable membranes inside the dialysis machine

  3. Solutes filter out of the blood, across the membrane and into a fluid called dialysate

  4. The concentration gradient between the blood and the dialysate fluid causes water and solutes to diffuse out of the blood and across the membrane
• Haemodialysis requires good access to an abundant blood supply
• In the acute setting, a Vas Cath (central venous catheter) is used for haemodialysis with two lumens, one to remove the blood and one to put the blood back in
• Anticoagulation with citrate or heparin is necessary to prevent blood clotting in the machine and during the process
• The amount of water and solutes removed from the blood can be controlled depending on the patient’s clinical condition and reason for dialysis
• Options for haemodialysis


  • Continuous renal replacement therapy (CRRT)
  • Intermittent haemodialysis (IHD)
• Continuous renal replacement therapy involves continuously performing dialysis 24 hours a day and is commonly used for patients requiring haemodialysis in the ICU
• Intermittent haemodialysis involves running the machine and performing dialysis for set periods, for example, 3-12 hours, before taking a break from dialysis
• Last updated


  August 2021