Haemodialysis options, techniques, complications

1. Big picture

Haemodialysis (HD) is a renal replacement therapy in which the patient’s blood is circulated through an extracorporeal circuit and a dialyzer removes uremic toxins, potassium, acid, and excess water. It does not cure chronic kidney disease; it replaces selected excretory functions of the kidney. Endocrine functions such as erythropoietin production and vitamin D activation must still be treated medically.

For the exam, think of haemodialysis in 4 layers:

1. Why dialysis? → uremia, hyperkalemia, acidosis, fluid overload, intoxication
2. How does it work? → diffusion + ultrafiltration ± convection
3. How do we access blood? → AV fistula, AV graft, catheter
4. What can go wrong? → hypotension, cramps, disequilibrium, bleeding, infection, access failure

Dialysis initiation should be based on symptoms and refractory complications, not serum creatinine alone. KDIGO emphasizes starting dialysis for clinical indications such as uremic symptoms, refractory acid-base/electrolyte problems, uncontrolled volume or blood pressure, or progressive nutritional/cognitive deterioration. ([KDIGO][1])

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