Renal Therapeutics III: Renal Replacement Flashcards Preview

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Flashcards in Renal Therapeutics III: Renal Replacement Deck (41):
1

What is the aim of renal dialysis?

For patients with GFR

2

What are the 2 general techniques of renal dialysis?

Haemodialysis
Peritoneal dialysis

3

Which 2 processes does dialysis try to mimic?

Ultra-filtration followed by reabsorption

4

How is ultra-filtration carried out in haemodialysis?

Artificial membrane
Fast cycles of fresh dialysis fluid = more effective than peritoneal dialysis

5

How is ultra-filtration carried out in peritoneal dialysis?

Patient's own peritoneal membrane
Dialysis reaches equilibrium before fluid change

6

When is dialysis used?

ARF (in oliguric phase)
CRF
Drug overdose
Poisoning

7

What is required in order to mimic ultra-filtration?

Membrane similar to glomerular basement membrane
Differs in pore size

8

How is water removed in haemodialysis?

By hydrostatic force

9

How is water removed in peritoneal dialysis?

By osmotic pressure (between blood and dialysis fluid)

10

How is waste removed during dialysis?

Blood is exposed (through a membrane) to a solution with a low concentration of substances to be removed

11

How is conservation of useful substances mimicked?

Tubular reabsorption does not exist
Replacement dietary supplementation oradding substances to dialysis fluid = transfer to patient

12

Why is heparin added to the blood during dialysis?

Anticoagulant
To prevent thrombosis in the blood circuit of the dialysis machine
Prevents air bubbles in blood getting into body

13

What does the dialysis fluid remove from the blood?

Urea
Creatinine
Potassium
Calcium (also in)
Sodium (also in)
Plasma water

14

What does the blood take up from the dialysis fluid?

Calcium (also out)
HCO3-
Sodium (also in)

15

Name the 4 haemodialysis techniques

Conventional haemodialysis
Haemofiltration
High-flux haemodialysis
Haemodiafiltration

16

What is conventional haemodialysis?

Low-flux membranes allow diffusive, but little convective solute removal
Middle molecule clearing is poor

17

What is haemofiltration?

Purely convective treatment
Poor small molecule clearance
Middle molecule clearance excellent
Not a long term treatment for ESRF

18

What is high-flux haemodialysis??

Highly permeable membranes used
= Good diffusive removal of middle molecules and small solutes

19

What is haemodiafiltration?

Haemofiltration (convective) but high flux haemodialysis (=highly permeable membranes)

20

List 5 side effects of haemodialysis

Fatigue
Low blood pressure - due to fluid loss
Muscle cramps - during dialysis due to fluid loss
Itchy skin - due to potassium build up, can be managed by a low potassium diet
Staphylococcal infections

21

What is peritoneal dialysis?

Home-based renal replacement therapy for patients with ESRF
2L of sterile dialysis fluid (dialysate) runs directly into the peritoneal cavity using a cathetar
Dialysis takes place between the blood in peritoneal capillaries and the dialysate, across the peritoneal membrane
Dialysate drained out

22

How is water removed from the blood in peritoneal dialysis?

The dialysate contains lots of glucose = osmotic gradient
Therefore water can be removed via osmosis
Amount of water removal can be adjusted by altering glucose concentration

23

How is the pH of the blood buffered?

By absorption of lactate and bicarbonate from the dialysate

24

What are the 3 techniques of peritoneal dialysis?

Intermitted peritoneal dialysis (IPD)
Continuous ambulatory peritoneal dialysis (CAPD)
Automated peritoneal dialysis (APD)

25

What is intermitted peritoneal dialysis (IPD)?

Hospitalised patients
Carried out over 24-48 times over 1-2 days
30 mins each
Repeated 2-3 times weakly

26

What is continuous ambulatory peritoneal dialysis (CAPD)?

Patient carries fluid in abdomen continuously
Changed 2-5 times daily
Closest method to normal kidney function

27

What is automated peritoneal dialysis (APD)?

Machine to switch between bags
used at home
More rapid cycle
Night-time exchanges might be enough

28

How can drugs be given in peritoneal dialysis?

Can be given in the CAPD fluid (abdomen)
e.g. antibiotics and insulin

29

List 2 common problems with peritoneal dialysis

Infection - peritonitis or exit site
Hyperglycaemia - glucose in dialysate causes this and obesity, especially in CAPD

30

List 2 advantages of PD over HD

Patient autonomy and independence
Lifestyle advantages (e.g. easier work and travel)

31

List 2 disadvantages of PD vs HD

Peritonitis and exit site infection
Patient or carer needs to be able to perform technique

32

List 3 things that would make a deceased person's kidney less attractive to donate

If the deceased donor has suffered from:
Diabetes Insipidus
Hypothermia
Problems with hormone levels

33

What is histocompatibility?

Tissue compatibility

34

What are the 2 important immunological criteria for histocompatibility?

Blood group
Human leucocyte locus-A (antigen compatibility)
Better matching kidney = reduced immunosuppressant doses

35

Describe the process of the surgical procedure of a kidney transplant

Organ placed extraperitoneally (peritoneum preserved for eventual dialysis)
Connected to blood circulation and and ureter implanted to bladder
Original kidneys usually left in except if problems e.g. hypertension, stones, tumours etc

36

Name the 3 types of rejection which could occur after a transplant

Hyperacute or immediate rejection
Acute rejection
Chronic rejection

37

Explain what a hyperacute/immediate rejection is

Caused by pre-existing antibodies
Happens within hours
Untreatable and rare
Results in renal vascular thrombosis

38

Explain what an acute rejection is

Most common form
T cell-mediated response to antigens
Results in vascular and tubular damage
Unspecific symptoms

39

Explain what a chronic rejection is

After the first few months
Immune-complex deposition within glomeruli and renal vessels
Leads to glomerulonephritis = irreversible

40

What are the 3 areas of medical management for renal transplants?

1. Initial choice and subsequent modulation of immunosuppressant regimen to prevent early & acute rejection
2. Management of complications and side effects of immunosuppressant therapy
3. Management of poorly function renal transplant

41

What are main problems that patients experience from immunosuppressant therapy?

Hypertension
Malignancy (caused by the cytotoxic agents)
Vascular diseases
Infections