Hypokalemia

  • Severe intradialytic hypokalemia can occur even when the dialysate contained a higher potassium concentration than the predialysis serum potassium concentration1
  • The cause of the hypokalemia is a rapid shift of potassium from the extracellular to the intracellular space secondary to correction of acidosis
  • Dialysis induced hyperkalemia is rare.
  • Reported causes include:
    • History suggesting prolonged potassium loss
    • Marked acidosis
    • Baseline moderate hypokalemia

Prevention and Treatment

  • Excess potassium removal during HD can prolong QTc interval on EKG preferentially and predispose to arrhythmia2
  • Try to keep post dialysis serum potassium 2-3 mEq/L
  • Use dialysate with 3.0 mEq/l of potassium in patients with CAD and/or on digoxin, unless there is chronic, severe hyperkalemia
  • Never use 0 mE/L potassium dialysate. Use of very low dialysate potassium (1 mEq/L) should be discouraged. Modelling of dialysate potassium could be helpful3

References:

  1. Wiegand CF, Davin TD, Raij L, Kjellstrand CM. Severe hypokalemia induced by hemodialysis. Arch Intern Med 141:167-170, 1981
  2. Cupisti A, Galetta F, Caprioli R, Morelli E, Tintori GC, Franzoni F, Lippi A, Meola M, Rindi P, Barsotti G. Potassium removal increases the QTc interval dispersion during hemodialysis. Nephron 82:122-126, 1999
  3. Morrison G, Michaelson EL, Brown S, Morganroth J. Mechanisms and prevention of cardiac arrhythmias in chronic hemodialysis patients. Kidney Int 17:811-819, 1980