Critical care: Renal

Question 1

Who is eligible for renal replacement therapy in critical care?

Answer 1

RENAL CAUSES: Rapidly rising serum creatinine, urea and uraemia complications, hyperkalaemia, Severe metabolic acidosis, diuretic-resistant pulmonary oedema, Oliguria or anuria
NON-RENAL CAUSES: Management of fluid balance, Clear toxins, correct electrolyte balance, temp control, remove inflammatory mediators in sepsis

Question 2

Describe the principle of haemofiltration?

Answer 2

Blood run alongside isotonic dialysis solution past a semi-permeable membrane - if there is excess or lack of any products they will move along the concentrations gradient into or out of the blood

Different fluids can be chosen depending on what the patients requirements are.
Will need to supplement phosphate and potassium

Question 3

What is the major problem with the blood coming into contact with a foreign substance and how do we counter this?

Answer 3

Major problem is the blood tendency to CLOT under these conditions
This is countered using CITRATE - this binds to the calcium in the blood using it up and stopping it from activating the clotting cascade

Could also consider giving the patient UFH or LWMH

Question 4

What is the most appropriate site for haemo-filtration?

Answer 4

A central vein (subclavian or femoral)

Femoral has a higher risk of infection subclavian has a higher risk of stenosis to the vein

Question 5

What complications are common in haemofiltration?

Answer 5

Increased haemodynamic instability
Clotting
Stenosing or irreparably damaging the veins