Dialysis

Question 1

What are the functions of the kidneys?

Answer 1

• Excretion of nitrogenous waste products
• Maintenance of acid and electrolyte balance
• Control of blood pressure
• Drug metabolism and disposal
• Activation of vitamin D
• Production of erythropoietin

Question 2

What functions of the kidneys cannot be replaced by dialysis?

Answer 2

• Activation of vitamin D

- Production of erythropoietin

Question 3

End stage renal disease (ESRD)

Answer 3

Irreversible damage to a person’s kidneys so severely affecting their ability to remove or adjust blood wastes that, to maintain life, he or she must have either dialysis, or a kidney transplant

Question 4

When may a patent with CKD be asymptomatic?

Answer 4

-Until CKD stage 4 or 5 the patient may be asymptomatic

Question 5

What is the syndrome of advanced CKD called?

Answer 5

Uraemia

Question 6

How do uraemic symptoms manifest?

Answer 6

Uraemic symptoms can involve almost every organ system but the earliest and cardinal symptom is malaise and fatigue

Question 7

What is renal replacement therapy?

Answer 7

The means by which life is sustained in patients suffering from end-stage renal disease.

Question 8

When is renal replacement therapy usually indicated?

Answer 8

Usually indicated when eGFR <10ml/min

Question 9

What types of renal replacement therapy are there?

Answer 9

• Renal transplant
• Haemodialysis
• Peritoneal dialysis
• Conservative kidney management

Question 10

How can haemodialysis be delivered?

Answer 10

• Home haemodialysis

- Satellite/hospital haemodialysis

Question 11

How can peritoneal dialysis be administered?

Answer 11

• Continuous ambulatory peritoneal dialysis (CAPD)

- Intermittent peritoneal dialysis (IPD)

Question 12

Dialysis

Answer 12

Dialysis is a process whereby the solute composition of a solution, A, is altered by exposing solution A to a second solution, B, through a semipermeable membrane.

Question 13

What are the principles of dialysis?

Answer 13

• Diffusion

- Ultrafiltration

Question 14

What are the pre-requisites for dialysis?

Answer 14

• Semipermeable membrane (artificial kidney in haemodialysis or peritoneal membrane)
• Adequate blood exposure to the membrane (extracorporeal blood in haemodialysis, mesenteric circulation in PD)
• Dialysis Access vascular in haemodialysis, peritoneal in PD
• Anticoagulation in haemodialysis

Question 15

What types of access are there for haemodialysis?

Answer 15

Permanent

• AV fistula
• AV prosthetic graft

Temporary

• Tunnelled venous catheter
• Temporary venous catheter

Question 16

What is the name of the solution used in dialysis?

Answer 16

Dialysate

Question 17

How is maximum efficiency of the removal of waste products achieved?

Answer 17

• Blood and dialysate run in opposite directions
• This means that the concentration difference is maintained at either side.
• This means waste will continue to filter into the dialysate maximising removal from the blood

Question 18

What intake restrictions are there for dialysis patients?

Answer 18

• Fluid restriction dictated by residual urine output checked by interdialytic weight gain
• Dietary restriction of potassium, sodium and phosphate

Question 19

How is clotting prevented in the dialysis machine?

Answer 19

Heparin pump

Question 20

What is involved in the process of peritoneal dialysis?

Answer 20

• A balanced dialysis solution is instilled into the peritoneal cavity via a tunnelled, cuffed catheter, using the peritoneal mesothelium as a dialysis membrane
• After a dwell time the fluid is drained out and fresh dialysate is instilled

Question 21

What does the dialysate used in peritoneal dialysis contain?

Answer 21

• The dialysate contains a balanced concentration of electrolytes
• Glucose is the most common osmotic agent for ultrafiltration of fluid

Question 22

Why do dwell times need to be adjusted in peritoneal dialysis?

Answer 22

The peritoneal transport characteristics can vary from high transporter to low transporter

Question 23

What are the possible complications of peritoneal dialysis?

Answer 23

• Exit site infection
• Tunnel infection
• PD peritonitis
• Technical
• Ultrafiltration failure
• Encapsulating peritoneal sclerosis

Question 24

What technical complications may there be in peritoneal dialysis?

Answer 24

• Tube related problems

- Abdominal wall hernia

Question 25

Where can the bacteria come from in PD peritonitis?

Answer 25

- Gram positive usually a skin contaminant - Gram negative usually bowel origin - Mixed: suspect complicated peritonitis e.g. perforation

Question 26

What are the indication for dialysis in ESRD?

Answer 26

- Advanced uraemia, (GFR 5-10 ml/min) - Severe acidosis (bicarbonate <10 mmol/l) - Treatment resistant hyperkalaemia (K >6.5 mmol/l) - Treatment resistant fluid overload - Nephrologist’s clinical judgment is important

Question 27

How is fluid balance maintained in haemodialysis patients?

Answer 27

- Usually restricted to 500-800 ml/24 hours | - Intake allowed = urine output +insensible loss

Question 28

How is fluid balance maintained in peritoneal dialysis patients?

Answer 28

- Usually more liberal intake as continuous ultrafiltration is often achieved - Less restriction on fluid intake

Question 29

What drugs are dialysis patients usually on?

Answer 29

- Erythropoietin injections - IV iron supplements - Activated vitamin D - Phosphate binders - heparin - Water soluble vitamins - Antihypertensives

Question 30

What are the possible complications of haemodialysis?

Answer 30

CV problems - Intra-dialytic hypotension and cramps - Arrhythmias Coagulation - Clotting of vascular access - Heparin related problems Other - Allergic reactions to dialysers and tubing - Catastrophic dialysis accidents (rare)

Question 31

What factors contribute to the choice of dialysis modality?

Answer 31

- Patient choice (involves education and shared decision making) - Patient related factors - Perceptions of effectiveness - Cost and remuneration (not applicable in Scotland)

Question 32

What are the limitations of dialysis?

Answer 32

- It is a woeful substitute for the kidneys - It is not right for everyone - Mortality rates

Question 33

What type of care is involved in conservative kidney management?

Answer 33

Supportive care

Question 34

What supportive care is available in conservative kidney management?

Answer 34

- Priority for symptomatic management - Holistic multi-professional approach - Anticipatory care planning - Randomised control trial ongoing for dialysis versus CKM for older adults with co-morbidity