Kinetics of the metal cations magnesium, calcium, copper, zinc, strontium,barium, and lead in chronic hemodialysis patients

Background: Dialysis patients are at risk of developing trace element imbal ances. To further elucidate the origin of these potential trace element imb alances, plasma and dialysis fluids concentrations of the elements barium ( Ba), calcium (Ca), copper (Cu), lead (Pb), magnesium (Mg), strontium (Sr) a nd zinc (Zn) of seven maintenance dialysis patients were investigated. Pati ents and methods: In each hemodialysis session 10 to 15 samples of each, wh ole blood and dialysis liquid before and after passing the artificial kidne y were collected. Concentrations of elements were determined by inductively coupled plasma mass spectrometry following strict quality control schemes to guarantee the accuracy and precision of the results. Results: Plasma con centrations of Cu and Zn continuously increased during hemodialysis. Plasma Cu remained within the reference range for healthy adults, whereas plasma Zn was always at or below the reference range in our patients. The behavior of Ca and Sr exhibited extraordinarily strong similarities both in plasma and dialysis liquids, although concentrations of Sr are approximately 2000 times lower. Plasma Ca and Sr were at or above the upper level of the refer ence range. Plasma Mg concentrations decreased during clinical treatment, b ut were at the end of dialysis still more than 50% higher than the high end of the reference range. Although concentrations of Ba in dialysis fluids w ere approximately 10 times lower than in plasma, plasma Ba concentrations ( similar to 23 mu g/l) were significantly elevated compared to plasma Ba of healthy adults. Initial concentrations of Pb in plasma (0.74 mu g/l) were i ncreased by similar to 15% during the clinical treatment and were always hi gher than the high limit of the reference range. Dialysis liquids had appro ximately the same Pb concentrations (0.5 to 1.3 mu g/l) as found in the pla sma of our patients but with higher concentrations at the inlet of the dial yzer. Conclusion: This study could give an insight into the kinetics of tra ce element concentrations during dialysis, the clinical relevance of which needs to be further elucidated.