Intro to dialysis

Question 1

What are the indications for dialysis

Answer 1

• Hyperkalaemia resistant to medical treatment
• Pulmonary oedema/fluid overload resistant to diuretics
• Symptoms of uraemia-poor appetite,vomiting, weight loss, lethargy & fatigue, itching
• Acidosis

Question 2

What are the aims of dialysis

Answer 2

• Remove waste products
• Remove excess water
• Maintain electrolyte and acid-base balance

Question 3

Outline the different types of dialysis

Answer 3

1. )Haemodialysis
   - Hospital(in centre)
   - Satellite unit
   - Home
2. )Peritoneal
   - Home based
   i. ) continuous ambulatory peritonaeal dialysis (CAPD)-this is the most portable
   ii. )Automated peritoneal dialysis(APD)

Question 4

What is a major issue with doing dialysis at home

Answer 4

you need very pure water, you can’t just use any tap

Question 5

Outline the need for water purification in dialysis

Answer 5

• Needs to be pure as it’s in contact with blood
• Goes thoroughly a series of reverse osmosis procedures to purify it
• Need to ensure it’s not high in K as you don’t want ti give this to the patient
• 120L of water is needed per session

Question 6

Outline use of an arteriovenous fistula in dialysis

Answer 6

• Native artery& vein
• Radiocephalic, brachiocephalic, brachiobasilic
• Matures in 4-8 weeks
• 2 needles usual
• Blows (needle extravasates and causes a bruise)
• Stenoses
• Thrombosis
• The rate of withdrawal needed could cause a vein to collapse cos the pressure is insufficient. This therefore creates a vessel where you can pull blood out at the rate you require without the vein collapsing
• Continuous puncturing of the artery isn’t a good idea cos you’ll have prolonged bleeding
• No plastic involved
• This wouldn’t be useful for someone who needs immediate dialysis because after this operation you need about 4-8weeks before the vein matures/ateriolises such that it can be used
• created for HEMODIALYSIS TREATMENTS

Question 7

Outline the use of a graft in dialysis

Answer 7

• Can put plastic inside if the patient doesn’t have good vessels (typically diabetics)
• Can be used straight away
• PFTE connects native artery and vein
• ‘artifical vein’
• Forearm, upper arm, leg
• The HeRO Graft is a hemodialysis access graft for patients who are failing fistulas or grafts or are catheter-dependent due to the blockage of veins leading to the heart.

Question 8

What are the possible complications of using a graft in dialysis

Answer 8

• Stensoses
• Thromboses
• Infection

Question 9

Outline use of a catheter during dialysis

Answer 9

• Tunnelled catheter: comes directly underneath the skin so this reduces the risk of it falling out of infection
• If pt doesn’t have 6-8weeks and they need it ASAP or has high levels of toxins in their body it may not be safe to give them an anaesthetic
• In the meantime you can do dialysis via a catheter

Question 10

Outline the principles of dialysis

Answer 10

• determine the composition of the dialysate
• Things you want to maintain as neutral, you should have in the same conc. as blood eg sodium
• High conc of bicarbonate as you want to give this to the pt as they are acidotic
• Solute movement by diffusion down conc. gradient
• end result=blood solute conc falls
• Patients have to restrict their fluid intake (1/2L of fluid) and diet

Question 11

Outline the principles of filtration

Answer 11

• Water & solute movement by filtration down pressure gradient
• end result= blood vol falls

Question 12

What are the complications of dialysis

Answer 12

• Hypotension
• Septicaemia
• Bleeding
• Clotting
• Dialyser reaction
• Air embolus

Question 13

Outline the principles of peritoneal dialysis

Answer 13

• Makes use of peritoneal membrane as semi-permeable membrane
• Creation of an osmotic gradient by addition of an osmotic agent (glucose)
• Fluid is removed by ultra filtration caused by osmotic gradient
• Solutes are transported by diffusion
• Membrane characteristics vary between pts

Question 14

What are the benefits of peritoneal dialysis ?

Answer 14

• Done by pt at home/work
• No need to attend hospital/dialysis centre
• More likely to be able to lead a normal life/travel

Question 15

What are the requirements for peritoneal dialysis?

Answer 15

• Physical: pt has to be able to lift 2kg bags
• Storage space
• Hygiene
• Some residual kidney function