Hydrogen ion balance in dialysis therapy

Area of Science:

• Nephrology
• Biochemistry
• Physiology

Background:

• Maintaining hydrogen ion balance (H+B) is crucial in dialysis therapy.
• Acetate and bicarbonate are common buffers used in dialysis, each with distinct metabolic effects.
• Understanding H+B dynamics is essential for optimizing dialysis treatment.

Purpose of the Study:

• To develop and validate a model for describing H+B during acetate and bicarbonate dialysis.
• To quantify metabolic hydrogen ion (H+) generation and buffer repletion during dialysis.
• To compare the cumulative H+B between acetate and bicarbonate dialysis therapies.

Main Methods:

• Developed a model incorporating metabolic H+ generation and net buffer repletion.
• Metabolic H+ generation was linked to protein catabolic rate and ion removal.
• Buffer repletion was calculated from acetate and bicarbonate flux during dialysis.

Main Results:

• The model demonstrated that metabolic H+ generation equals 0.77 times protein catabolic rate plus net ion removal.
• Cumulative H+B was significantly different between the two therapies: -7 ± 28 mmol/week for acetate vs. -175 ± 45 mmol/week for bicarbonate (P < 0.001).
• A strongly negative initial H+B was observed upon switching from acetate to bicarbonate dialysis.

Conclusions:

• Acetate dialysis is associated with a less negative H+B compared to bicarbonate dialysis.
• Conversion from acetate to bicarbonate dialysis therapy leads to an initial, significant negative H+B.
• The physiological implications of this initial negative H+B shift warrant further investigation.