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)
What is automated peritoneal dialysis (APD)?
Machine that performs exchanges overnight (done at home)
What are the benefits of haemodialysis?
- Is hospital based for elderly patients (social network)
- Less protein loss
- Shorter treatment times
- Highly efficient small solute clearances
- No lag time to commence (PD requires several weeks before catheter can be used and training needed)
What are the complications of haemodialysis?
- Hypotension (post dialysis)
- Infections of vascular access (especially cannulae)
- Time consuming
- Hospital based
- Bleeding risk
What are the contraindications of haemodialysis?
- Severe cardiac failure
- Vascular access issues
What is regarded as the best form of RRT?
Renal transplantation
What are the benefits of renal transplant?
- Allows dietary freedom
- Independence
- Corrects renal anaemia
Disadvantages of peritoneal dialysis?
- Requires increased patient responsibility
- Storage of equipment and fluid
- Membrane failure - finite lifespan
- Hyperglycaemia / glucose load
- Protein losses (not good for diabetics)
- Complications: hernias, peritonitis
Advantages of PD?
- Home based
- Increased flexibility
- Preservation of residual renal function
- No need for vascular access
- Less fluid restriction (maintain residual UO)
- Better mobility
- No anti-coagulation
Disadvantages of HD?
Hospital based (some home HD) Scheduled treatment - shifts Vascular access problems Haemodynamic stress Bleeding risk Post dialysis - hypotension Complications: Infections, hypotension
Advantages of HD?
Less protein loss Shorter treatment times Social network at dialysis centre Highly efficient small solute clearances No lag time to commence (PD requires several weeks before catheter can be used and training needed)
Who is considered for renal transplant?
Patients on dialysis or approaching dialysis (pre-emptive transplantation)
Patients must also be fit enough for the surgery
What are the complications of renal transplant?
Infections (immunosuppression)
Malignancy (immunosuppression)
Rejection
Recurrent kidney disease
What are the types of kidney donors?
- Deceased donors (after brainstem death or after circulatory death)
- Live donors (related, unrelated)
What is haemofiltration?
Patients requiring renal replacement therapy in the ICU will be attached to a machine providing continuous renal support.
How does haemofiltration work?
This works in a similar
way to the dialysis machines but is a much more gentle treatment.
When is it important to use haemofiltration?
This is important for patients who are acutely unwell and have cardiac instability who would not tolerate “normal” dialysis.
Is the old kidney removed in renal transplant?
No
Where is the new kidney placed?
Lower abdomen
How is the new kidney vein and artery joined?
The kidney’s vein is joined to your own vein called the iliac vein which drains blood from the leg
The artery is joined to the iliac artery which supplies the leg with blood
What is kidney transplant half life?
The time that 50% of the patients who survived beyond the first year post transplant are still alive with a functioning kidney
- Deceased donor 12 years
- Live Donor 15-20 years
What are the long term side effects of immunosuppression?
- Skin cancer (use sun cream)
- Post transplant lymphoproliferative disorder (PTLD) (weight loss, fever)
- Opportunistic infections (cytomegalovirus)
