Renal Replacement Therapy Flashcards
What are the functions of the kidney?
•Water and waste:
- regulation of total body water
- waste excretion e.g. urea/creatinine
- regulation of body electrolytes
- regulation of acid-base balance e
•Hormonal
- mineral metabolism
- production of renin
- production of EPO
- glucose metabolism
What are the indications for emergency dialysis?
- Medically resistant hyperkalaemia
- Medically resistant pulmonary oedema
- Medically resistant acidosis
- Uraemic pericarditis
- Uraemic encephalopathy
- Specific drug overdoses
What are the symptoms of uraemia?
- Anorexia
- Vomiting
- Itch
- Restless leggs
- Weight loss
- Metallic taste
What are the RRT options?
- Haemodialysis: hospital/home
- Peritoneal dialysis: CAPD/APD
- Renal transplant : cadaveric or living
What are the modality considerations in RRT?
- Lifestyle
- Frailty
- Vascualr access
- Time to travel to and from the hospital
- Carers
- Physical: concurrent medical problems e.g. disseminated malignancy, severe dementia, severe psychiatric disease
Give a basic overview of how haemoldialysis works
- Arterial circuit: blood is pumped out of the patient and enters the dialysis filter where there dialysis fluid flowing in a counter current direction to the blood
- Diffusion of solutes out of the blood into the fluid occurs
- Blood leaves the filter in the venous circuit and passes through an air filter to ensure no air embolism and enters the patient
What are the 2 aims of haemodialysis?
- Removal of solutes e.g. potassium, urea by diffusion across a semi-permeable membrane
- Removal of fluid ‘ultrafiltration’: hydrostatic filtration
What are the types of haemodialysis access?
- TCVC - large bore line through the internal jugular
* AVF- arteriovenous fistula (can get graft if veins not good enough)
What are the practicalities of haemodialysis?
- Hospital or home based but hospital is much more common
- Standard 4 hours, 3 times a week
- Home based offers greater flexibility and empowerment but need carer, space and capital investment
What are the complications of haemodialysis?
•Solute/fluid movement complications:
- crash (acute hypotension)
- cramps (due to sodium loss)
- fatigue
- hypokalaemia
- dialysis disequilibrium (sudden shift of urea, osmotic drag on brain)
•Complications of invasive treatment:
- access problems
- blood loss
- air embolism
What are the types of peritoneal dialysis?
- CAPD: continuous ambulatory peritoneal dialysis
* APD: automated peritoneal dialysis (machine works while sleeping
Explain the principles of peritoneal dialysis
- Dialysate filled peritoneal cavity (lots of glucose)
- Mesothelium and peritoneal capillary wall separate fluids
- Water, urea, creatinine and electrolytes and macromolecules move into dialysis fluid, glucose moves out
What are the practicalities of peritoneal dialysis?
- Home based therapy
- Better with some residual renal function
- Different glucose concentrations of dialyse to provide more or less ultrafiltration
- dialyse contains other electrolytes like in HD
- Gradual treatment- no good for Aki
- Simple procedure once taught
- Maintains independence
What are the complications of peritoneal dialysis?
Solute/fluid movement
•Glucose load- development or worsening control of diabetes
•Hypoalbuminaemia
Complication of invasive treatment
•Infection - peritonitis
•Mechanical - hernia, diaphragmatic leak, dislodged catheter
•Peritoneal membrane failure - PD becomes less effective
•Encapsulating peritoneal sclerosis
Which patients are not suitable for peritoneal dialysis?
- Grossly obese
- Intra-abdominal adhesions
- Frail
- Home not suitable
