TRACE-ELEMENT BALANCE IN PATIENTS UNDERGOING HEMODIALYSIS

Concentrations of the essential trace elements chromium, cobalt, coppe r, molybdenum, nickel, selenium and zinc, as well as of the element al uminum were determined pre-, intra- and postdialytically in the plasma , whole blood and dialysate of patients undergoing hemodialysis, both before inflow and after outflow of the dialysator. The effect of the t reatment was determined from the temporal and the arterio-venous diffe rences in concentration from the start to the end of dialysis. By the simultaneous determination of total protein and hematocrit the hemocon centration was obtained and the absolute changes in trace element leve ls were estimated. The values in whole blood and hematocrit were used to determine the content of the elements in the blood cells and to det ect shifts between the plasma and the cells. For evaluating the system the mass balances were calculated for each element as the sum of the system's inflow and outflow. The high chromium value of 82 nmol/l in p lasma increased during dialysis (absolutely 47%) due to an uptake out of the contaminated dialysate, the content of the blood cells remained unchanged. The cobalt levels in plasma (10 nmol/l) were below the det ection limit; the median in the whole blood (11 nmol/l) was unchanged at the end of dialysis. The plasma values of copper lied in the refere nce range, with an absolute reduction of 5.7% postdialytically. The hi gh molybdenum concentration - reduced during dialysis by 57% in plasma - was still above the range of normals after dialysis. The increased plasma levels of nickel (initially 75 +/- 38 nmol/l) showed a further increase (absolutely 33%) at the end of the session. The plasma value of selenium, predialytically 0.63 +/- 0.15 mumol/l (below the referenc e range), increased slightly due to dialysis. The zinc levels in plasm a and whole blood were in the lower normal range initially and unchang ed in plasma or blood cells postdialytically. The aluminum load (1.30 +/- 0.62 mumol/l) showed a slight reduction due to the treatment.