Renal Replacement Therapy Flashcards
What is RRT?
Renal replacement therapy is a term used to describe supportive treatment for those
with renal failure that would otherwise be life threatening.
It encompasses
haemodialysis, peritoneal dialysis, haemofiltration and renal transplantation.
What is done for patients who choose to not have RRT?
Palliative measures
What is the national average eGFR for commencing dialysis in CKD?
Around 8 m./min/1.73m2
What is peritoneal dialysis? How is it done?
The peritoneal membrane is used as a semipermeable membrane. A tube is placed directly into the peritoneal cavity and dialysis fluid is run into the peritoneal cavity.
What does most dialysis fluid contain? Why?
Glucose to create an osmotic gradient
When the dialysis fluid is run into the peritoneal cavity, what happens?
Uraemic toxins pass into the dialysis fluid down a conc gradient (created by glucose in fluid) and water is dragged by osmosis into the peritoneal cavity.
When is peritoneal dialysis performed?
It can be performed intermittently throughout the day or overnight using an
automated machine.
What are the benefits of peritoneal dialysis?
Can be done at home
What are the complications of peritoneal dialysis?
- Peritonitis
- Sclerosing peritonitis (due to exposure of peritoneum to glucose for so long)
What are the contraindictations of peritoneal dialysis?
- Presence of a hernia
- Abdominal hernias
- Severe arthritis-unable to perform technique
- Previous surgery with adhesions
What is haemodialysis?
Blood is pumped through an artificial kidney (layers of semipermeable
membranes known as a dialyser) with dialysis fluid flowing in the opposite direction.
Uraemic toxins pass across the membrane by a process of diffusion and water can
be removed from the blood.
How often do patients tend to have haemodialysis a week?
Three, four hour sessions per week at the hospital.
What volume of blood flow does haemodialysis require?
At least 200ml per minute through the dialyser
What are the 2 routes of vascular access during haemodialysis that gives the blood flow needed?
- An arteriovenous fistula
2. Large bore double lumen cannula (also used in emergency)
Why are aterio-venous fistulas preferred choice of access for dialysis?
Much lower rate of infection compared to central venous catheters (CVC’s)