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
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 measures [3]
600ml if anuric
1l HD
1.5l PD
What are complications of dialysis [11]
IHD - high risk Intra-dialytic hypotenion, Hypertension Arrythmia, Endocarditis Infection Clotting, Bleeding due to anti-coag Allergy Altered drug pharmacokinetics Altered nutrition
What causes hypotension
Become too dry
Feel crampy
What is catastrophic dialysis [5]
Massive haemorrhage Air embolism Acute allergy Acute haemolytic Dialysis disequilibrium syndrome
What is dialysis disequilibrium syndrome [3]
Between cerebral and blood solutes
Leads to cerebral oedema
Start dialysis gradually
Early signs include nausea, headache, vomiting, and restlessness.
How can PD be carried out [2]
Continuous ambulatory PD 4x daily
Automated BP overnight
peritoneum is used as a semi-permeable membrane; a permanent Tenckoff catheter is inserted across the peritoneal cavity and fluid is infused in a dwell time for 4-8h allowing solutes to diffuse slowly across; ultrafiltration achieved by dextrose solution
How long can you do PD for [2]
2 types of PD
5 years
High complications
Types:
- continuous ambulatory where exchange lasts 30-40 mins and dwell time 4-8h
- automated where pt sleeping and 3-5 exchanges performed overnight
What does PD require [5]
Semipermeable dialyser membrane = peritoneal Mesenteric blood Access Fill bag Drain bag
What access for PD
Tunnelled venous catheter in abdomen
How does PD work [3]
Dialysis solution (high dextrose) into peritoneal cavity
Drains out waste
Fresh dialysate instilled
What does dialyse contain
Balance of electrolyte
Glucose most common
What are complications of PD [9]
Exit site infection Tunnel infection PD peritonitis Tube malfunction Abdominal wall hernia Ultrafiltration failure as membrane destoryed Encapsulating peritoneal sclerosis Metabolic Fluid retention
What causes tube malfunction
Constipation
What metabolic issues [4]
Obesity
Hyperglycaemia
Malnutrition
Protein wasting
What are symptoms of PD peritonitis [6]
Cloudy fluid - WCC + neutrophils Abdo pain N+V Fever GI upset Systemic upset
What is the best way to treat ESRD
Kidney transplant into R iliac fossa
What are common organisms in PD infection [2]
S epidermis
S aureus
