Haemdialysis / Peritoneal Dialysis Flashcards
What does haemodialysis involve [2]
Diffusion
Ultrafiltration
Blood is passed over a semi-permeable membrane against dialysis fluid flowing in the opposite direction; blood is meeting a less concentrated solution so solutes diffuse down a concentration gradient whereas large solutes do not clear
ultrafiltration then creates a negative transmembrane pressure to clear excess fluid;
What does haemodialysis require [6]
Duration?
Semipermeable membrane (dialyser) Dialysate pumped counter current to blood (contained electrolyte) Artificial kidney Adequate blood exposure Anti-coagulation Dialysis access
3x a week 3-5h
When do you not use haemodialysis [2]
If haemdynamic instability
Use if kidney is the only issue
When do you use haemofiltration [2]
ITU if haem-dynamic instability
Continuous but may delay mobilisation
GFR 8-10
What can be used for access [3]
Central line in emergency
AV fistula
AV prosthetic graft
What can you use whilst waiting for fistula / graft [2]
Tunneled venous catheter (Permcath)
Temporary non-tunnelled venous catheter
What does a Permcath do [5]
Tunneled catheter Goes underneath skin Runs into vein Reduce infection Lasts months - 1 year
What does a non-tunnelled do [2]
Direct into vein if fistula not ready
Lasts 2 weeks
What are the risks of lines [4]
Infection
Thrombosis
Pneumothorax
Central venous stenosis
What veins are used for catheter
R+L jugular
What veins / artery are used for fistula [4]
Snuff box - younger as may need to use more
Brachiocephalic - most common
Radiocephalic
Brachiobasilic
What do you need for fistula [3]
Adequate artery
Adequate vein to connect to artery to train fistula
8 weeks before
What do you do before fistula [2]
Examination
Duplex USS
What are indications for graft / tunnelled catheter over fistula [4]
Vein not suitable - congenital or been used
Frailty
Heart issues
Fistula failure
What causes fistula failure [7]
Thrombosis Hypotension Hypercoagulable Proximal venous or arterial stenosis Trauma Steal syndrome Infection
What is steal syndrome
Features [5]
Too much blood goes through fistula leading to ischaemia of the hand 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 of fistula [4]
Address hypotension
Urgent thrombectomy if thrombosis
Fistuloplasty if stenosis
Temporary line
How do you monitor renal function on dialysis [2]
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
Daily requirement
K levels
1ml/kg/day
How do you work out how much to lose each dialysis [2]
Patients have target weight which is considered euvolemic
Reduce target weight if overload
How does diet change when start dialysis [6]
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
