Week 5 - F - Dialysis - Types and complications Flashcards
What is the primary and secondary option for renal replacement therapy?
Primary option - renal transplantation Secondary option - dialysis
What are the indications for referral to the renal unit? (nephrologist)
Nephrotic syndrome Stage 3 CKD with protein:creatinine ratio > 100mg/mmol Stage 3 CKD with progress - GFR falling by >20% over six months Stage 4 CKD Haematuria - when exlcusion of urology in older patients
What are the indications for urgent dialysis in acute kidney injury?
Hyperkalaemia Severe acidosis - pH less than 7.15 Fluid overload - leads to pulmonary oedema Uraemic pericarditis Severe uraemai - greater than 40 Drug overdoes
How does dialysis work? (for haemo or peritoneal)
Blood is passed over a semi permeable membrane against dialysis fluid flowing in the opposite direction The waste in the blood moves across the semi permeable membrane from high concentration to a low concentration of solutes
What molecules are able to diffuse across the semi permable membrane?
diffusion of small solutes occurs down the concentration gradient. Larger solutes do not clear as effectively.
Dialysis allows for the removal of toxins that build up with end stage kidney disease Which substances go from patinet to di
Allows urea potassium and sodium to move into dialysis fluid and bicarbonate to flow into the patient
In haemodialysis there needs to be an adequate blood flow rate What is the rate of blood flow required?
Needs about 300ml/min of blood to work
Again, what are the substances which come out in the dialysate?
Urea, potassium, sodium and other toxins are diffused out
What is used as the semi-permeable membrane in haemodialysis?
The dialyzer creates an artificial membrane in haemodilaysis It is composed of thousands of tiny hollow synthetic fibres
In haemoadialysis, how is the process of filtration achieved to several litres of excess fluid?
Ultrafiltration is used to regulate the distribution of water between the blood and dialysate. A negative pressure is applied to the wastecompartment of the dialyzer causing the water and dissolved solutes to move from blood to waste and this remo
Dialysis is not very efficient which is why transplant is preferred, what is the minimum a patinet must come in for the dialy
Minimum of 3 times a week for 4 hours each week
There are 4 main diet restrictions in haemodialysis, what are they?
1litre of fluid per day No salt diet -helps prevent thirst and maintains fluid balance Low phosphate diet and phosphate binders Low potassium diet
What is the gold standard of haemodialysis access?
An arteriovenous fistula Joins an artery and a vein to make an enlarged thick walled vein called an Areteriovenous Fistula
The pros of an arteriovenous fistula is that there is a good blood flow and unlikely to cause infection What are the cons?
It can block Can cause ischaemia to the distal arm Requires maturation of 6 weeks before it can be used
What is the ischaemia to the distal arm known as in ateriovenous fistula?
This is known as steal syndrome - dialysis-associated steal syndrome (DASS)
How is the excess water removed in peritoneal dialysis? (ie, how is ultrafiltraton achieved)
An osmotic agent such as glucose is added to the dialysate and this cause water to move via osmosis
How do both continous peritoneal dialysis and automated peritonel dialysis work? How much time is given for the fluid exchange?
Continuous peritoneal dialysis - 4 bag changes per day - fluid drained then fresh fluid instilled with a max of 30miins for exchange Automated peritoneal dialysis - 1 bag of fluid stays in all day and overnight and a machine cleans the fluid at night
If the patinet does not have a gradual build up in haemodialysis, an increasingly rare syndrome known as the dialysis disequilibrium syndrom can occur What is seen in DDS?
Cerebral oedema and seiizures BUN - blood urea nitrogen
