Renal Replacement Therapy Flashcards
What are patients GFRs usually at when they commence RRT
5-10
Explain how haemodialysis (HD) works
blood passed over semi-permeable membrane against dialysis fluid flowing in opposite direction
Solutes diffuse across conc gradient
Hydrostatic gradient clears XS fluid
What is the preferred method of access in HD?
av fistula
How soon before HD should an av fistula be made and why?
8 weeks to avoid infection risk associated w central venous dialysis catheters
How often do HD patients have to dialyse and how long for?
3x a week or more for 3+ hrs at a time
What are the advantages of dialysing every day on HD?
increases does nd improves outcome
Can HD patients dialyse at home?
yes
What are the problems associated w HD?
- ACCESS - AV fistula thrombosis, stenosis, steal syndrome
Tunneled venous line infection, blockage or recirculation of blood - DIALYSIS EQUILIBRIUM - cerebral oedema - neuro sx, start HD gradually
- Hypotension
- INFECTION at site
- ARRHYTHMIAS
Explain how peritoneal dialysis (PD) works
peritoneum is a semi-permeable membrane
Catheter is inserted in peritoneal cavity and fluid is infused
Solutes diffuse across slowly
Ultrafiltration - add osmotic agents (glucose, glucose polymers) to fluid
Continuous process w intermittent drainage + refilling of peritoneal cavity, performed at home
What are the problems associated w PD
- catheter site infection or blockage
- Peritonitis or sclerosing peritonitis
- Hernia
- Loss of membrane function over time
- Constipation
- Hypoglycaemia
What is haemofiltration? When is it indicated?
Used in CCU when HD not possible due to low BP
Water is cleared by +ve pressure, dragging solutes into waste by convection
Ultrafiltrate (waste) replaced w volume of ‘clean’ fluid either before or after the membrane
what are the absolute contraindications to transplant?
cancer w mets
What are the temporary contraindications to transplant?
active infection
HIV
unstable CVD
What are the relative contraindications to transplant?
CCF, CVD
What are the main types of kidney transplant?
- Living donor
- Deceased - brain death donor, expanded criteria donor (older kidney or pt w hx of CVA, BP or CKD), donor after cardiac death
What is the advantage of living donor transplant?
best graft function and survival, especially if HLA matched
What does a donor after cardiac death transplant increase the risk of ?
delayed graft function
What drugs are used in immunosuppression at the time of transplant? After?
monoclonal abs
after:
calcineurin inhibitors (tacrolimus, cyclosporin)
antimetabolites - azathioprine
What drugs are used following acute rejection of transplant? what are the SE of these drugs that u need to be aware of?
Glucocorticoids
SE:
BP, hyperlipidaemia, DM, impaired wound healing, osteoporosis, cataracts, skin fragility
What are the complications of transplant?
- Surgical - inf etc
- Delayed graft function
- Rejection
i. acute - rx w high dose steroids + immunosuppression
ii. chronic - progressive dysfunction - Infection:
- 1 month - hospital acquired/donor
- 1-6 months - opportunistic therefore give CMV and pneumocystis jiroveci prophylaxis
- 6-12 months - community acquired - Malignancy - skin, post transplant lymphoproliferative disorder and gynaecologist
- CVD
What are the overall complications of RRT
- Mortality: CVD (raised BP->Ca/PO4 dysregulation -> vascular stiffness ->inflammation ->oxidative stress ->abnormal endothelial function)
- Protein calorie malnutrition
- Renal bone disease - high turnover, renal osteodystrophy, osteitis fibrous
- Infection - uraemia -> granulocyte + T cell dysfunction w sepsis
- Amyloid - beta-2 microglobulin accumulation in long term dialysis -> carpal tunnel syndrome/ arthralgia
