Calcium flux during hemodialysis

A system of equations has been derived, and examined, to decribed membrane permeability and calcium fluxes within a commonly used hemodialyzer, the Mini-Kiil. By a statistical technique of sequential multiple regression analysis, factors which might influence these variables were tested on data derived from 74 hemodialysis periods in 5 patients. Calcium flux from plasma to dialysate was influenced positively by dialysate calcium concentration and plasma volume flow and negatively by dialysate volume flow. Calcium flux from dialysate to plasma was influenced positively by dialysate calcium concentration and plasma volume flow and negatively by plasma phosphate concentration. Net calcium flux from dialysate to plasma was influenced positively by the calcium gradient (dialysate calcium minus plasma ultrafiltrable calcium) and plasma volume flow and negatively by plasma phosphate concentration (coefficient of multiple correlation =0.970). Because of the magnitude of regression coefficients, manipulations of the dialysate calcium concentration and plasma phosphate concentration were concluded to be the most practical means of adjusting calcium delivery during dialysis.