Renal Pathology CKD/AKI/RRT Flashcards
Define dialysis
Dialysis is an exogenous method of filtration that mimics the excretory function of the kidney to remove excess fluid, electrolytes and waste
What are the different methods of renal replacement therapy?
Hemodialysis
Hemofiltration
Peritoneal dialysis
Transplant
Conservative management
When can short term dialysis be used?
AEIOU
A - acidosis (refractory)
E - electrolyte abnormalities (hyperkalemia)
I - Intoxication (overdose)
O - Oedema (pulmonary oedema refractory)
U - Uraemia symptoms (seizures/unconscious)
What is the main indicator for long-term dialysis?
End stage renal failure - stage 5 CKD
What are the long-term dialysis options?
Hemodialysis or peritoneal dialysis
Describe the process of haemodialysis
Blood is taken out of the body, passed through a dialysis machine and pumped back into the body.
Semipermeable membrane inside the dialysis machine allow for molecules to filter out of the blood into the dialysate.
Why are citrate or heparin used during haemodialysis?
Used as anticoagulants to prevent blood clotting in the machine
What is the standard hemodialysis prescription in the UK?
3-4 hour sessions 4 times a week
Aim for 12 hours of dialysis per week
Describe peritoneal dialysis
This method uses the peritoneal membrane to filter the blood.
A dialysate solution containing dextrose is added into the peritoneal cavity and filtration can occur from the blood across the peritoneal membrane into the dialysate in the peritoneal cavity
Why is glucose instilled in the dialysate for peritoneal dialysis?
Glucose in the dialysate creates an osmotic gradient for fluid removal while not being able to diffuse across the peritoneal membrane itself
Why is the peritoneal membrane an appropriate membrane for dialysis?
It is a semipermeable membrane and has a rich blood supply so fluid and waste can easily be filtered
What are the two types of peritoneal dialysis?
Continuous ambulatory PD
Automated PD
Describe the differences between CAPD and APD
CAPD involves the pt changing their dialysate throughout the day. The dialysate needs to be changed every 4 hours, approximately 4 times throughout the day
APD utilises a machine that pumps dialysate solution into the peritoneal cavity and draining it continuously for 8-10 hours overnight
Why is an arteriovenous fistula created in dialysis patients?
An arteriovenous fistula is a connection created between an artery and a vein that allows for increased blood flow.
The fistula provides an easy access high pressure blood vessel appropriate for hemodialysis
What are the common locations of an arteriovenous fistula?
Radiocephalic fistula at the wrist
Brachiocephalic fistula at the antecubital fossa
Brachiobasilic fistula at the upper arm - less common
