Artificial Kidney and Liver

Question 1

Convective Clearance

Answer 1

–> Solvent Drag

• amount of water coming across the membrane

convective clearance = SC *Q
SC = sieving coefficient –> number & dimension of pores –> membrane type: lowflux vs. highflux
Q = Filtration flow

Question 2

Pressure Drop in Dialyzer

Answer 2

• favors convection

- proportional to 1/r^4 –> Hagen Poisseuille’s Law

Question 3

Functions of the Liver

Answer 3

• metabolism of carbohydrates, fat and proteins
• storage of vitamins
• synthesis of coagulation factors and synthesis of the bile acids
• degradation of toxic substances

Question 4

Reasons for Liver failure

Answer 4

• hepatic viruses
• abuse of pharmaceutical drugs
• liver ischemia
• liver toxins (alcohol …)
• bacterial infections

Question 5

Regeneration of the liver

Answer 5

• liver regeneration after injuries and adaptation to size changes
• after split-liver of 2/3 hepatic mass, full restauration of original liver mass within 7 days
  partial hepatectomy –> proliferation of all cells within the liver
• hepatocytes with unlimited capacity for regeneration

Question 6

Why is therapy by hemodialysis in case of liver failure not sufficient?

Answer 6

• end products are protein-bound and hydrophobic
• -> for dialysis they must be hydrophilic
• healthy liver: hydrophilisation –> secretion by liver
  BUT: liver failure: no hydrophilisation –> accumulation in blood

Question 7

Two tasks that have to be done in case of liver treatment

Answer 7

1) Detoxification: filter and adsorber
- -> Adsorption of hydrophobic molecules

2) Secretion

Question 8

How can you reach a higher clearance of large molecules?

Answer 8

If the inner diameter of the capillaries of a dialyzer gets reduced

Question 9

What does hemodiafiltration also use in comparison to hemofiltration?

Answer 9

hemodiafiltration uses diffusion