3: Dialysis Flashcards
Which three process are involved in dialysis?
Diffusion
Convection
Adsorbption
What builds up in end stage kidney disease and needs to be removed by dialysis?
Toxins
urea, sodium, potassium
How is metabolic acidosis associated with end stage kidney disease corrected?
Sodium bicarbonate
What passes from the dialyte to the blood by diffusion to correct metabolic acidosis?
Sodium bicarbonate
Why does end stage kidney disease cause metabolic acidosis?
Kidneys can’t filter H+
How is the movement of water controlled in dialysis?
Convection / ultrafiltration
controlled by altering the pressure rather than the conc. gradients of electrolytes
How is the transport of plasma proteins controlled in dialysis?
Size of the pores in the dialyser
by absorption
Which processes control
a) electrolyte
b) water
c) plasma protein
transport in dialysis?
a) Diffusion (solute gradients)
b) Convection / ultrafiltration (pressure gradient)
c) Absorption (size of the pores)
How long do patients tend to be on haemodialysis for per week?
4 hours
3 times a week
minimum
What lifestyle restrictions are put on patients on dialysis?
Fluid restriction
Salt restriction
Which electrolyte imbalances are people with CKD at risk of?
Hypernatraemia (> fluid overload)
Hyperkalaemia (>arrythmia)
Hyperphosphataemia (bone disease)
so they’re all restricted
How is a patient hooked up to haemodialysis?
Fistula
artery and vein joined together (e.g radial artery & bacilic vein)
What are complications of using a fistula for dialysis?
Stenosis
Thrombosis
regularly reviewed
Fistulas are (planned / emergency) procedures for people with CKD.
planned operation
no good in emergency presentations
How is dialysis given to patients with emergency presentations of CKD / renal failure?
Tunneled venous catheter
internal jugular or femoral vein
What is a complication of using a tunneled venous catheter for dialysis?
Infection
Which organism usually causes infections associated with tunneled venous catheters?
Staph aureus
Which antibiotics are given for dialysis line infections?
IV vancomycin
Apart from infection, what are possible complications of dialysis?
Hypotension - decrease in blood volume due to filtration
Haemorrhage from ruptured fistula
How does peritoneal dialysis work?
Peritoneum has loads of capillaries
Fluid into peritoneal cavity, comes into close contact with capillaries
How are
a) solutes
b) water
removed from the blood by peritoneal dialysis?
a) Diffusion (high > low)
b) Osmosis (dialysate has high glucose conc.)
Why is glucose included in the dialyte in peritoneal dialysis?
Increases the osmolarity of the dialyte, encouraging osmosis FROM the peritoneal capillaries
The peritoneal capillaries contain glucose themselves and so have their own osmolarity which needs to be overcome
How often are patients given continuous (bags) peritoneal dialysis for?
How long does each session take?
QDS
20-30 mins
What types of peritoneal dialysis are given
a) throughout the day
b) at night?
a) Continuous
b) Automated
Which bacteria can cause infection in patients on peritoneal dialysis?
Skin commensals (staph, strep)
Gut commensals (E. coli, klebsiella)
What are GI complications of peritoneal dialysis?
Hernia
Peritonitis
What are common causes of death in people on dialysis?
CVD - MI, stroke
Infection
