Replenishing Alkali During Hemodialysis: Physiology-Based Approaches

Area of Science:

• Nephrology
• Biochemistry
• Dialysis Therapy

Background:

• Intermittent hemodialysis aims to correct acid-base balance by replenishing bicarbonate lost due to endogenous acid production and metabolic acidosis between treatments.
• Traditional empirical methods for determining bicarbonate dosage result in varied global hemodialysis prescriptions.
• Current bicarbonate bath concentrations lead to rapid blood bicarbonate increases early in treatment, followed by a net loss due to body buffer responses.

Purpose of the Study:

• To investigate novel hemodialysis prescription strategies that moderate the rate of blood bicarbonate increase and mitigate the body's buffer response.
• To propose alternative approaches for optimizing bicarbonate delivery during intermittent hemodialysis.

Main Methods:

• Evaluating the efficacy of a lower bicarbonate bath concentration combined with increased acetate concentration.
• Assessing a stepwise increase in bicarbonate bath concentration during treatment.
• Considering reduced bicarbonate bath concentration as a sole intervention for patients with low endogenous acid production.

Main Results:

• The conventional approach leads to a rapid initial rise in blood bicarbonate, followed by a counterproductive buffer response that depletes extracellular bicarbonate.
• Proposed new strategies aim to create a more controlled and efficient bicarbonate replenishment during hemodialysis.
• These interventions seek to prevent the "futile and unnecessary event" of bicarbonate loss.

Conclusions:

• Current hemodialysis bicarbonate prescriptions may be suboptimal, causing inefficient acid-base management.
• Modulating the rate of bicarbonate increase and the body's buffer response through adjusted dialysis prescriptions is warranted.
• Further studies on alternative bicarbonate delivery methods, such as lower concentrations with acetate or stepwise increases, are recommended for improved patient care.