Dialysis

Question 1

How is diffusion involved in dialysis?

Answer 1

It moves solutes from high to low concentration to equalise the gradient

Question 2

What is the purpose of dialysis?

Answer 2

To remove toxins from the body which build up in ESKD

Question 3

What substances are removed in dialysis?

Answer 3

Urea, potassium, sodium, creatinine

Question 4

Dialysis allows the infusion of what?

Answer 4

Bicarbonate

Question 5

What is the blood flow rate in dialysis?

Answer 5

300mls/min

Question 6

What substances go into the blood in dialysate?

Answer 6

Pure H2O, Na+, HCO3-, K+, glucose

Question 7

How does haemodialysis get rid of water? What is it known as?

Answer 7

It is dragged across a semi-permeable membrane in response to a pressure gradient. This is known as ultrafiltration.

Question 8

Adsorption in dialysis mainly affects what?

Answer 8

Plasma proteins and any solutes stuck to them

Question 9

How are plasma proteins removed in membrane binding?

Answer 9

They stick to the membrane surface and are removed by membrane binding

Question 10

Which absorbs protein bound solutes better- high or low flux membranes?

Answer 10

High flux

Question 11

What is the difference between haemodialysis and haemofiltration?

Answer 11

Dialysis = diffusion // Filtration = convection

Question 12

What are some factors which affect the convective transport of a molecule across a membrane?

Answer 12

Water flux, membrane pore size, pressure difference, viscosity of fluid, electrical charge

Question 13

What is the minimum time that patients should be on dialysis?

Answer 13

4 hours, 3 times a week

Question 14

If a patient on dialysis is anuric, how much should fluid be restricted to per day?

Answer 14

1 litre (including food fluid)

Question 15

Patients on dialysis should have a diet low in what?

Answer 15

Salt, potassium and phosphate

Question 16

Why are patients given a low salt diet?

Answer 16

To reduce thirst and help with fluid balance

Question 17

What are some foods which are high in potassium which should be avoided in dialysis patients?

Answer 17

Banana, chocolate, potato, avocado

Question 18

What is the gold standard for dialysis access?

Answer 18

Fistula

Question 19

What happens in a fistula?

Answer 19

Join an artery and a vein to make an enlarged, thick walled vessel

Question 20

What are some pros of a fistula?

Answer 20

Good blood flow, less likely to cause infection

Question 21

What are the cons of.a fistula?

Answer 21

Requires surgery, 6-12 weeks maturation before use, can limit blood flow to the distal arm, can thrombus or stenose

Question 22

What is a tunnelled venous catheter?

Answer 22

A catheter inserted into a large vein

Question 23

Where is a tunnelled venous catheter usually inserted?

Answer 23

Internal jugular or femoral vein

Question 24

What are some pros of a tunnelled venous catheter?

Answer 24

Easy to insert and can be used immediately

Question 25

What are some cons of a tunnelled venous catheter?

Answer 25

High risk of infection, can become blocked, can damage central veins causing problems with future line insertion

Question 26

An infection of a tunnelled venous catheter is most likely to be with what? What kind of infections can this cause?

Answer 26

Staph aureus : discitis or endocarditis

Question 27

What are some investigations for a venous catheter infection?

Answer 27

Blood cultures, FBC and CRP, exit site swab

Question 28

What antibiotics are used for an infected tunnelled venous catheter?

Answer 28

Vancomycin +/- gentamycin

Question 29

What are some complications of dialysis?

Answer 29

Hypotension, blood leaks, loss of vascular access, hyperkalaemia and cardiac arrest

Question 30

How are water and solutes removed in peritoneal dialysis?

Answer 30

Water = osmosis, solutes = diffusion

Question 31

What drives the osmosis of water in peritoneal dialysis?

Answer 31

The high glucose concentration in dialysate fluid

Question 32

How many bags of fluid are used in continuous peritoneal dialysis? How long does each last for?

Answer 32

4 bags of 2l fluid, each for 20-30 mins

Question 33

What happens in automated peritoneal dialysis?

Answer 33

1 bag of fluid stays in all day and an overnight machine drains fluid

Question 34

What type of infection may occur in peritoneal dialysis? Why may this occur?

Answer 34

Peritonitis or exit site infection due to contamination or gout bacteria translocation?

Question 35

What organisms can cause contamination of a site of peritoneal dialysis?

Answer 35

Staph, strep, diphtherioids

Question 36

What organisms may be present in an infection of peritoneal dialysis caused by gut bacteria translocation?

Answer 36

E. coli and klebsiella

Question 37

Apart from infection, what are some other complications of peritoneal dialysis?

Answer 37

Peritoneal membrane failure and hernias

Question 38

What blood tests indicate the need to start dialysis?

Answer 38

eGFR < 5, urea > 40, unresponsive academia, resistant hyperkalaemia

Question 39

What are some symptoms which indicate the need to start dialysis?

Answer 39

Fatigue, itch, fluid overload, nausea, anorexia, vomiting

Question 40

How is starting on haemodialysis built up?

Answer 40

1st session 90-120 mins, subsequent sessions build up to 4 hours

Question 41

Too rapid a correction of uraemia toxin levels can lead to disequilibrium syndrome. What can this cause?

Answer 41

Cerebral oedema and seizures

Question 42

What are some medical reasons that patients should be removed from dialysis?

Answer 42

PVD, cerebrovascular and CV disease, cancer

Question 43

What are some social reasons that patients should be removed from dialysis?

Answer 43

Increasing fraility and inability to cope at home