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Dialysate Potassium Arrhythmia Risk — ESENeph MCQ

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ModerateHaemodialysisDialysate Potassium Arrhythmia RiskESENeph

A 60-year-old man on haemodialysis has the following dialysis prescription: blood flow 300 mL/min, dialysate flow 500 mL/min, dialysate sodium 138 mmol/L, dialysate potassium 2 mmol/L, dialysate calcium 1.25 mmol/L, dialysate bicarbonate 32 mmol/L. His pre-dialysis potassium is consistently 6.5 mmol/L. What dialysate potassium adjustment could be considered?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: A — Reduce dialysate potassium to 1 mmol/L – but this increases the risk of arrhythmia from rapid potassium shifts

Lowering dialysate potassium concentration increases the transmembrane potassium gradient, promoting more potassium removal during dialysis. However, a very low dialysate potassium (1 mmol/L or below) creates a large, rapid potassium shift that may trigger cardiac arrhythmias (particularly dangerous in patients on digoxin or with cardiac disease). A dialysate potassium of 2 mmol/L is standard; going to 1 mmol/L should be used cautiously. Interdialytic potassium management (diet, binders) is the safer approach. Individualised dialysate prescriptions based on pre-dialysis electrolytes are increasingly advocated.

Reference: ERA-EDTA 2019 – HD Prescription; Kovesdy et al 2007 – Dialysate K and Mortality