Renal Replacement Therapy

Question 1

Define dialysis:

Answer 1

A method of artificial filtration in place of the kidneys which involves removing waste products, fluid and solutes.

Question 2

What are some of the indications for acute dialysis?

Answer 2

Use mnemonic AEIOU:
Acidosis
Electrolyte imbalances
Intoxication
Oedema
Uraemia

Question 3

What are the main indications for long term dialysis?

Answer 3

End stage renal failure (usually from CKD)

When any acute problems become long term

Question 4

What are the three main options for long term dialysis?

Answer 4

Continuous ambulatory peritoneal dialysis
Automated peritoneal dialysis
Haemodialysis

Question 5

What form of dialysis can be used in the acute / short term setting?

Answer 5

Haemofiltration

Question 6

In peritoneal dialysis, what acts as the filtration membrane?

Answer 6

The peritoneal membrane

Question 7

What is the basic mechanism behind peritoneal dialysis?

Answer 7

1) The peritoneal cavity is filled with a special dialysis solution
2) Ultrafiltration occurs across the peritoneal membrane from the blood to the solution
3) Dialysis solution is then taken away and replaced

Question 8

What form of catheter is used in peritoneal dialysis?

Answer 8

Tenckhoff Catheter - used for inserting and removing the dialysis solution

Question 9

How does automated dialysis occur in peritoneal dialysis?

Answer 9

The peritoneal dialysis occurs overnight. A machine constantly replaces the dialysis fluid in the abdomen overnight to optimise ultrafiltration.
Takes roughly 8-10 hours

Question 10

List some of the main complications of peritoneal dialysis?

Answer 10

• Bacterial Peritonitis
• Peritoneal sclerosis
• Ultrafiltration failure
• Weight gain
• Psychosocial impacts

Question 11

Why is bacterial peritonitis a common S/E in peritoneal dialysis?

Answer 11

Infusions of glucose solutions allow the peritoneum to become a great environment for bacterial growth

Question 12

What are the two main options for accessing a good blood supply in haemodialysis?

Answer 12

AV fistula

Tunneled cuff catheter

Question 13

How regular can haemodialysis be for a patient?

Answer 13

Roughly 4 hours 3 times a week

Question 14

Where is a tunnelled cuffed catheter usually placed?

Answer 14

Subclavian or jugular vein

Tip sits in the SVC or right atrium

Question 15

There are two lumens in a tunnelled cuffed catheter, red and blue. WHy?

Answer 15

Red - blood exits the body

Blue - blood re enters the body

Question 16

What is the purpose of the Dracon ring?

Answer 16

This is inserted around the catheter to promote healing and adhesions of the tissue to the cuff to allow for it to be more permanent. It also reduces bacterial infection risk

Question 17

What are the main complications of a Tunnelled cuffed catheter?

Answer 17

Bacterial infections

Clots

Question 18

What vessels are typically used to make an AV fistula?

Answer 18

Brachio-cephalic
Radio-cephalic
Brachio-basilic (rarer)

Question 19

What is typically heard on auscultation of an AV fistula?

Answer 19

Continuous machinery murmur

Question 20

How long does an AV fistula take to mature?

Answer 20

Anywhere from 4 weeks to 4 months

Question 21

What are some of the complications of an AV fistula?

Answer 21

Aneurysms 
Infection
Thrombosis
Stenosis
STEAL syndrome
High output heart failure

Question 22

What is STEAL syndrome?

Answer 22

This is when there is inadequate flow to the lower limb below the AV fistula as the fistula STEALS blood from it and diverts it straight to the venous system
Limb ischaemia occurs

Question 23

How does high output heart failure occur in AV fistulas?

Answer 23

Blood flows very quickly from arterial to venous system through the fistula
Rapid return of blood to heart
Increased preload on heart
Hypertrophy of heart muscle muscle — heart failure

Question 24

What is the mortality rate of dialysis?

Answer 24

20% on average yearly

Question 25

What is the main cause of mortality in dialysis patients?

Answer 25

Cardiovascular complications e.g. MI and CVA

Question 26

What can cause carpal tunnel syndrome increased fractures and arthralgia in long term dialysis patients?

Answer 26

Amyloid accumulation