Exchange of Alkali Trace Elements in Hemodialysis Patients:A Comparison with Na⁺ and K⁺

Abstract

Background: In the past, nephrologists have been troubled by electrolyte disturbances and consequently focused their attention on the importance of maintaining the concentrations of electrolytes within the normal range. However, information about the potential role of trace elements in chronic renal failure is scarce. Methods: During hemodialysis sessions, the concentrations of the five alkali metal cations lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs) have been determined in plasma and dialysis fluids of chronic hemodialysis patients by inductively coupled plasma mass spectrometry (Li, Rb, Cs) and by ion-sensitive electrodes (Na, K). Strict quality control schemes were applied to all analytical procedures to ensure accuracy and precision of the results. Results: The plasma concentrations of the elements Li, Cs, Rb, and K distinctly decreased to 29, 50, 69, and 71%, respectively, of their initial values during hemodialysis. Simultaneously, the concentrations of these elements in dialysis fluids at the outlet of the dialyzer increased approximately 13-fold for Rb, 11-fold for Li, 3-fold for Cs, and 2-fold for K as compared with the inlet values. The concentrations of Na in plasma and dialysis fluids were almost identical and did not change during hemodialysis. Conclusions: Li, Rb, and Cs were depleted in hemodialysis patients, although the plasma concentrations of these trace elements still remained within the reference ranges for healthy adults. Consequently, further studies are needed to elucidate the clinical importance and long-term effects of these trace element imbalances – for example, CNS disturbances associated with diminished concentrations of Rb – in hemodialysis patients.

Long-Term Changes of Plasma Trace Element Concentrations in Chronic Hemodialysis Patients

“…In previous studies, ICP-MS proved to be a very powerful analytical tool for the simultaneous determination of trace elements in whole blood, plasma and serum [3][4][5][6]15]. Therefore, in combination with strict quality control schemes, ICP-MS can considerably contribute to elucidate the meaning of trace elements in HD patients.…”

“…The final dialysate contained the following components: Na + 135-140 mmol/l and K + 0.5-2.5 mmol/l according to the patient's need, Ca 2+ 1.6 mmol/l, Mg 2+ 0.75 mmol/l, CH 3 COO -3.0 mmol/l, HCO -3 32.0 mmol/l and glucose 1.0 g/l, total osmolarity 291 mosm/l. Details are given elsewhere [5,6].…”

“…The centrifuged plasma was transferred into 2-ml sterile tubes (Nalgene ® , Nalge Company, Rochester, N.Y., USA). All samples were stored at 4°C in a refrigerator until they were mineralized [3,5]. During the observation period of 6 months, 3-5 blood samples before the start and after the end of the HD sessions of each patient were taken and subsequently plasma was prepared.…”

“…To reach that goal, whole blood was collected before and after HD, at baseline and during 6 months to investigate long-term changes of elemental compositions. Inductively coupled plasma mass spectrometry (ICP-MS), a very powerful and reliable analytical method for the ultra trace determination of elements in whole blood and plasma [3][4][5][6], was employed for this purpose.…”

Atomic spectrometry update. Clinical and biological materials, foods and beverages

“…Concentration changes of elements in plasma and dialysis fluids of seven patients on haemodialysis were followed by Krachler et al 27 by ICP-MS. In the patients' plasma, concentrations of Cu and Zn continuously increased during dialysis.…”