Dialysis - the practicalities Flashcards
What are the two forms of dialysis performed?
Haemodialysis
Peritoneal dialysis
What is haemodialysis?
Countercurrent flow in dialysis machine
Blood moves from the patient to the dialysate
Small molecules move via convection/ diffusion out of the blood into the dialysing fluid
What is peritoneal dialysis?
Uses the peritoneal membrane as a semipermeable membrane across which diffusion occurs
What is the advantage of peritoneal dialysis as opposed to haemodialysis?
Can be done at home - patient retains independence
What is renal replacement therapy?
Umbrella term that includes different treatment options for kidney disease patients
Kidney transplant
Hemodialysis
Peritoneal dialysis
How many times a week does haemodialysis take place?
4 hours 3 times a week
What conditions do patients undertake when performing haemodialysis?
Restriction to fluid intake
Medication
Dietary restriction to sodium, potassium and phosphate
What infrastructures need to be set in place for dialysis patients to receive treatment?
Need somewhere to dialyse - hospital unit, satellite or a home
Transport - take patient between unit and home
Medical and nursing unit
What types of vascular access exist for dialysis to be performed on patients?
Temporary
Tunnelled haemodialysis lines
What does temporary vascular access entail?
Dialysis lines are inserted into the large veins of the neck and groin
Immediate access to patients’ circulation in emergecy situation
What do tunnelled haemodialysis lines entail?
Line is tunnelled under the skin and emerges in chest wall
What are the advantages of tunneled haemodialysis lines?
Last longer - months to years
Infection rates are lower
What are complications of vascular access?
Infections - commonest
Dialysis line can become infected and spread to the bloodstream
Venous stenosis and thrombosis
What complications arise from fistulas?
Can be unsightly
Can infect
Form high cardiac output or vascular steal if overdeveloped, thrombosed or stenosed
What is a fistula?
Form from operations to join artery and vein
Anastomoses forms between artery and vein
Blood from the artery goes straight into the vein
Vein increases in size/ becomes arterialised
What is the point of Fistula formation?
Makes it possible to put needles into enlarged veins
Blood can be taken out of the body
Sent through to the dialysis machine
Blood is returned through dialysis machine
Complications of haemodialysis
Acute - hyperkalaemia
Fluid overload - peripheral oedema and fluid accumulation in the lungs
Tertiary hyperthyroidism - many years to develop
What causes the quality of life to diminish in haemodialysis patients?
Fluid and diet restrictions
Medications
Delays in transportation to and from the hospital
Dialysis - takes 4 hours a week
What is home haemodialysis?
Compact, small and easy to use dialysis units
Used in group of carefully selected patients
Gives greater autonomy for motivated patients
What is peritoneal dialysis?
Uses the peritoneum in the abdomen as a membrane across which fluids and dissolved substances are exchanged from the blood
How does peritoneal dialysis work?
Fluid is introduced through a permanent tube in the abdomen and flushed out
What are the two types of peritoneal dialysis that exist?
Continuous ambulatory peritoneal dialysis
Automated peritoneal dialysis
What are the characteristics of continuous ambulatory peritoneal dialysis?
- Tunneled catheter into the abdomen
- Dialysate fluids are drained into the abdomen via the peritoneal catheter by gravity
- Fluid is retained in the peritoneal cavity for around 4 hours = dwell time
- At the end - dialysate fluid is drained out via catheter and takes wastes from the body with it
How many exchanges of dialysis fluid a day in continuous ambulatory peritoneal dialysis?
4 exchanges a day
