Haemdialysis / Peritoneal Dialysis Flashcards
What does haemodialysis involve
Diffusion
Ultrafiltration
Through counter current system
What does haemodialysis require
Semipermeable membrane (dialyser)
Dialysate pumped counter current to blood (contained electrolyte)
Artificial kidney
Adequate blood exposure
Anti-coagulation
Dialysis access - high flow created from fistula
When do you not use haemodialysis
If haemdynamic instability
Use if kidney is the only issue
When do you use haemofiltration
ITU if harm-dynamic instability
Continuous but may delay mobilisation
What can be used for access
Central line in emergency
AV fistula - 6-8 weeks
- To check its working listen for murmur / thrill
AV prosthetic graft
What can you use whilst waiting for fistula / graft
Tunneled venous catheter (Permcath) - essentially a PICC line that is tunnelled to reduce infection
Temporary non-tunnelled venous catheter
What does a Permcath do
Tunneled catheter Goes underneath skin Runs into vein Reduce infection Lasts months - 1 year
What does a non-tunnelled do
Direct into vein if fistula not ready
Lasts 2 weeks
What are the risks of lines
Infection
Thrombosis
Pneumothorax
Central venous stenosis
What veins are used for catheter
R+L jugular or subclavian
What veins / artery are used for fistula
Snuff box - younger as may need to use more Brachiocephalic - most common Radiocephalic Brachiobasilic of non-dominant hand
What do you need for fistula
Adequate artery
Adequate vein to connect to artery to drain fistula
Allows blood to flow from high pressure artery to vein and bypass capillary system
What do you do before fistula
Examination
Duplex USS
What are indications for graft / tunnelled catheter over fistula
Vein not suitable - congenital or been used
Frailty
Heart issues
Fistula failure
What causes fistula failure
Thrombosis Stenosis Aneuyrsm Infection High output heart failure causing hypotension Trauma Steal syndrome
What is steal syndrome
Too much blood goes through fistula leading to ischaemia of the hand distal to the fistula Cold Pain Cramps Paresthesia Gangrene
What are signs of thrombosis
Absence of thrill or bruit
What are signs of stenosis
High pitched bruit
How do you manage failure
Address hypotension Urgent thrombectomy if thrombosis Heparin infusion Fistuloplasty if stenosis Temporary line
How do you monitor renal function on dialysis
URR (urea reduction ratio) - urea before and after dialysis
KTV = more accurate
Why can’t you use creatinine or eGFR
Fluctuates when on and off dialysis
What do you worry about
K levels
How do you work out how much to lose each dialysis
Patients have target weight which is considered euvolemic
Reduce target weight if overload
How does diet change when start dialysis
Fluid restriction Salt, K and phosphate restriction Protein and calories restriction Phosphate binder Vitamin supplements as lose water soluble Iron as lose when on dialysis
Why might you not need BP meds
Dialysis deals with salt and fluid retention if this is the cause of high BP
What fluid restriction
600ml if anuric
1l HD
1.5l PD
What are complications of haemodialysis
IHD - high risk Intra-dialytic hypotension Fluid overload causing hypertension Electrolyte imbalance Arrythmia Endocarditis Site infections Clotting / heparin issue Altered drug clearancee Altered nutrition Catastrophic dialysis
What causes hypotension
Become too dry
Feel crampy
What is catastrophic dialysis
Massive haemorrhage due to anti-coagulant Air embolism Acute allergy Acute haemolytic reaction DIC Dialysis disequilibrium syndrome
What is dialysis disequilibrium syndrome
Between cerebral and blood solutes
Leads to cerebral oedema
Start dialysis gradually
