Effect of Potassium Removal during Hemodialysis on the Plasma Potassium Concentration

Abstract

The effect of potassium removal by hemodialysis on the plasma potassium concentration (PK) was observed during 20 studies on 7 anuric patients. The following was observed: (1) The pattern of change in PK is consistent with at least a two-compartment distribution; hence, in contrast to urea, PK shows a marked postdialytic rebound and the simple equation for solute removal from a single pool cannot predict postdialysis PK. (2) The magnitude of the fall in PK correlated with the predialysis PK; this was not only due to increased potassium removal, but also due to a dependence of the apparent volume of distribution of potassium on the state of potassium balance. The fractional decrement in plasma potassium concentration, contrary to that of urea, is a function of predialysis concentration, and prediction of the effect of dialysis on plasma potassium concentration can assume neither a single pool nor a constant distribution volume for this ion.