Dialysis Flashcards
name the 3 concepts related to dialysis
diffusion
convection
adsorbtion
define diffusion
movement of solutes from high to low concentration to equalise the gradient
what does dialysis allow the removal of?
toxins which build in ESRD
urea
creatinine
potassium
sodium
what does dialysis allow the infusion of?
allow infusion of bicarbonate
pure H2O
the movement of water (and all solutes dissolved in it- convective solute drag) across a semi-permeable membrane in response to a pressure gradient
the above defines what?
convection
what is convection also known as?
ultrafiltration
what does adsorption affect?
plasma proteins
____ flux membranes adsorb protein-bound solutes better than ___ flux membranes
HIGH flux membranes adsorb protein-bound solutes better than LOW flux membranes
where do plasma proteins stick?
membrane surface and removed by membrane binding
______________ is diffusive but ___________________ is convective in nature
HAEMODIALYSIS is diffusive but HAEMODIAFILTRATION is convective in nature
in HDF, lots of things affect the efficiency of the convective transport. name some.
water flux membrane pore size pressure difference fluid viscosity shape, size and electrical charge of each molecule
what is the minimum HD/HDF prescription?
4 hours 3 times per week
decreasing HD time by __ mins increases your risk of death by 1%
decreasing HD time by 30 mins increases your risk of death by 1%
restriction for HD patients:
low… (4)
low fluid
low salt
low potassium
low phosphate
name the vessel that tunnelled venous catheters are usually placed into
internal jugular vein
infections in tunnelled venous catheters are caused by what organism?
staph. aureus
treatment of infected tunnelled venous catheters?
vancomycin and gentamicin
what is the gold standard for dialysis vascular access?
fistula
sites for fistulas?
radio-cephalic
brachio-cephalic
brachio-basilic transposition
pros and cons of fistula?
pros:
good flow and less likely to cause infection
cons:
surgery
can’t use for 6-12 weeks
‘steal arm’ - limit flow to distal arm
thrombose/stenose
state the acronym for haemodialysis reliable outflow graft
HeRO graft
what can go wrong in dialysis?
hypotension haemorrhage loss of vascular access arrhythmia cardiac arrest
water is removed via _______ in peritoneal diffusion
water is removed via OSMOSIS in peritoneal diffusion
how is PD driven?
high glucose concentration in dialysate fluid
name the 2 types of PD
CAPD - continuous ambulatory peritoneal dialysis
APD - automated peritoneal dialysis
which PD is at night and which is 4 x 2L bags per day?
APD - night
CAPD - 4 x 2L bags
PD complications?
infection - peritonitis
peitoral membrane failure
hernias
when do you start dialysis?
potassium?
eGFR?
urea?
metabolic acidosis?
resistant hyperkalaemia
eGFR < 7 ml/min
urea >40 mmol/L
unresponsive metabolic acidosis
when to start dialysis on symptoms?
nausea vomiting anorexia fatigue itch
