Ionized calcium during dialysis and ultrafiltration.

Area of Science:

• Nephrology
• Biochemistry
• Physical Chemistry

Background:

• Dialysis and ultrafiltration involve fluid and electrolyte shifts.
• Albumin solutions are used in some renal replacement therapies.
• Accurate measurement of ionized calcium is critical in clinical settings.

Purpose of the Study:

• To investigate the factors influencing ionized calcium changes during dialysis and ultrafiltration.
• To determine the role of albumin and electrolyte concentration on calcium levels.
• To assess the applicability of the Donnan theory to these physiological processes.

Main Methods:

• Monitoring ionized calcium levels during dialysis and ultrafiltration procedures.
• Utilizing albumin-containing solutions.
• Varying total electrolyte concentrations.
• Analyzing ion distribution and membrane potential.

Main Results:

• Ionized calcium changes were strongly correlated with total electrolyte concentration.
• Protein interference with the calcium electrode did not account for the observed changes.
• Observed ion distribution patterns were consistent with the Donnan theory.
• Evidence of a Donnan membrane potential was observed due to uneven sodium ion distribution.

Conclusions:

• Total electrolyte concentration is the primary determinant of ionized calcium shifts during dialysis/ultrafiltration with albumin.
• The Donnan theory accurately predicts ion distribution and membrane potential in this context.
• Clinical protocols should consider electrolyte balance for accurate calcium assessment.