dialysis

Question 1

what are the principles of dialysis?

Answer 1

diffusion
convection
adsorbtion

Question 2

what does dialysis do?

Answer 2

removes toxins that build up with ESKD (urea, creatinine, potassium and sodium)
allows the infusion of bicarbonate

Question 3

how does access get acquired in dialysis?

Answer 3

Arteriovenous Fistula (AVF)
Arteriovenous Graft (AVG)
Tunnelled Central Venous Catheter (TCVC)
Temporary Venous Catheter (Vascath)

Question 4

what is the rate of haemodialysis?

Answer 4

500ml/min (120l in 4 hr treatment)

Question 5

what is the difference between HDF and HD?

Answer 5

replacement of extra convective ultrafiltrate through the dialysis period
less symptomatic that HD
enhances recovery time

Question 6

what things affect the efficiency of the convective transport of a molecule across a membrane?

Answer 6

water flux
membrane pore size
the pressure difference applied to and across the membrane
the size, shape and electrical charge of each molecule

Question 7

what is a tunneled central venous catheter?

Answer 7

a catheter inserted into a large vein, usually the internal jugular
easy to insert and can be used immediately
high risk of infection
can become blocked
can cause damage to central veins making further insertion difficult

Question 8

what commonly causes infections in TCVC?

Answer 8

staph aureus
treat with vancomycin and gentamicin

Question 9

what can a staph infection through a TCVC cause?

Answer 9

endocarditis
discitis

Question 10

what is the gold standard for dialysis vascular access?

Answer 10

arteriovenous fistula

Question 11

where does the AVF take place?

Answer 11

radiocephalic
brachiocephalic
brachiobasilic

Question 12

what are the features of AVF?

Answer 12

good blood flow
less likely to cause infection
requires surgery
takes around 6-12 weeks to mature before it can be used
can limit blood flow to distal arm “steal syndrome”
can thrombose or stenose

Question 13

what can go wrong in haemodialysis?

Answer 13

hypotension
haemorrhage
loss of vascular access
arythmia
cardiac arrest

Question 14

what is peritoneal dialysis?

Answer 14

solute removal by diffusion of solutes across the peritoneal membrane
water removal by osmosis driven by high glucose concentration in dialysate fluid

Question 15

what can go wrong in peritoneal dialysis?

Answer 15

infection (peritonitis or exit site infection)
peritoneal membrane failure
hernias

Question 16

when is dialysis usually started?

Answer 16

based on blood tests
- resistant hyperkalaemia
- eGFR <7ml/minute
- urea>40mmol/L
- unresponsive metabolic acidosis

based on symptoms
- nausea
- anorexia
- vomiting
- profound fatigue
- itch
- unresponsive fluid overload

Question 17

what is the risk of too-rapid a correction of uraemic toxin levels?

Answer 17

disequilibrium syndrome
leads to cerebral oedema and possible confusion, seizures and occasionally death

Question 18

when is dialysis withdrawn?

Answer 18

medical reasons
- haemodynamic instability
-progressive dementia
-agitation
-cardiovascular event
-terminal cancer
social reasons
- increasing frailty and inability to cope at home
-especially common in old people