Dialysis Flashcards
Name the 6 functions of the kidney.
Metabolic waste excretion Endocrine functions Drug metabolism/excretion Control of solutes and fluid status Blood pressure control Acid/base balance
What is the aim of dialysis therapy?
Homeostasis
- removal of nitrogenous waste product
- maintenance of normal electrolytes
- maintenance of normal extracellular volume
- correction of metabolic acidosis
What are the absolute indications for renal replacement therapy?
Hyperkalaemia
Fluid overload
Uraemia
Acidosis
What are the chronic symptoms of uraemic syndrome?
Anorexia Metallic taste Weight loss Restless leg Itch Vomiting
What eGFR indicates someone should start renal replacement therapy?
No absolute rule
- generally between 5-10ml/min/1.73m2
- assessed on the basis of the individual
What are the renal replacement therapy options?
Transplant - living or dead Dialysis - haemodialysis - peritoneal dialysis - CVVH Conservative care
What is the aim of haemodialysis?
Removal of solutes via diffusion - e.g. potassium and urea
Removal of fluid via convection (osmotic pressureal
Describe how solutes are removed from the blood.
Patient’s blood is passed down a tube with a semipermeable membrane separating it form the dialysate (which is moving in the opposite direction)
The blood is passed down a concentration gradient, allowing the solutes to continuously pass into the dialysate, even as the blood solute concentration falls
Describe how blood volume is reduced in dialysis.
Patient’s blood is passed down a tube with a semipermeable membrane separating it form the dialysate (which is moving in the opposite direction)
The blood is passed down a pressure gradient, which forces the excess water out of the blood and into the dialysate
What are the practicalities of haemodialysis?
Hospital or home based - hospital more common
Standard - 4 hours, three times a week
Multiple other options (mainly home based)
- 6 hours, 3 times a week
- short daily dialysis
- daily overnight
Home based treatments are more flexible and empowering, but they need carers, space and capital investment
How is blood accessed from the body for haemodialysis?
Ateriovenous fistula
- radiocephalic
- brachiocephalic
Tunneled line
Name some complications of haemodialysis.
Hypotension Dialysis disequilibrium Cramps Fatigue Hypokalaemia Air emoblism Blood loss Access problems
What are the principle of peritoneal dialysis?
Peritoneal cavity filled with dialysate
Peritoneal membrane used as a semi-permeable membrane
- diffusion
- glucose used as an osmotic agent for osmosis
What are the practicalities of peritoneal dialysis?
Home based therapy
Better with some residual renal function
Different glucose concentrations of dialysate to provide more or less ultrafiltration
Dialysate contains other electrolytes like in haemodialysis
Gradual treatment (not for AKI)
Simple procedure
Maintains independence
What are the two types of peritoneal dialysis?
CAPD (continous ambulatory peritoneal dialysis)
- manual exchange performed by the patient
APD (automated peritoneal dialysis)
- machine performs the exchages whilst the patient is asleep more common)
What are the complications of peritoneal dialysis?
Infection - peritonitis Glucose load - development of diabetes Mechanical - hernia, diaphragmatic leak, dislodged catheter Peritoneal membrane failure Encapsulating peritoneal scerosis
In what patients is peritoneal dialysis not suitable?
Fat people
Intra-abdominal adhesions
Frail
Home not suitable
Who is conservative care used for in and why?
Frail and elderly population
- survival better if they are put on RRT, but the quality of life wont be
Symptom based management
Why choosing which RRT to use, what must be taken into consideration?
Lifestyle Frailty Vascular access Time - travel to and from the hospital Carer Physical - concurrent medical problems - severe dementia - severe psychiatric disease
What problems are not helped by dialysis?
Anaemia - need EPO and iron
Renal bone disease - need phosphate binders and vitamin D
Neuropathy
Endocrine disturbances
Not as good as transplant (only 10ml/min eGFR)
