Renal

Question 1

By what mechanisms might contrast cause AKI?

Answer 1

Direct nephrotoxicity of ROS
Imbalance of vasoconstriction vs vasodilatation
Increased O2 consumption
Contrast-induced diuresis
Increased viscosity of urine

Question 2

What are the risk factors of contrast-induced AKI?

Answer 2

1. Increasing age > 75
2. Renal impairment
   3.Nephrotoxic drugs
3. IV contrast vs oral
4. Contrast load

Question 3

What is the KDIGO classification of AKI?

Answer 3

Kidney disease: Improving global outcomes
Stage 1: 1.5-2 fold increase in Cr, > 26.5 increase, urine < 0.5 for 6-12 hours
Stage 2: 2-3 fold increase in Cr. Urine < 0.5 for > 12 hours
Stage 3: Cr > 354, > 3-fold increase, < 0.3 urine for > 24 hours or anuria for 12.

Question 4

How does CVVHF work?

Answer 4

Uses the principle of convection. There is bulk flow of solute and water down a hydrostatic pressure gradient across a semi-permeable membrane

Question 5

How does CVVHD work?

Answer 5

Utilises the principle of diffusion. There is countercurrent flow of blood and diasylate, with diffusion of solutes down a concentration gradient. The higher the diasylate (up to 500mls/min) and blood flow (200-300mls/min) the better maintained the concentraion gradient.