Dialysat

Dialysat, commonly spelled dialysate in many contexts, is a sterile, specially formulated fluid used in renal replacement therapy to remove waste products and excess fluid from the blood. It serves as the counterflow medium in dialysis, enabling diffusion and, in some systems, convection across a semipermeable membrane while remaining separate from the blood.

In hemodialysis, dialysate flows on the opposite side of the dialysis membrane from the blood. Its electrolyte and acid–base composition is adjusted to resemble normal plasma, supporting safe and effective waste removal and fluid balance. Typical dialysate formulations include electrolytes such as sodium, bicarbonate, calcium, and magnesium, with potassium levels customized to the patient’s needs. Bicarbonate is commonly used as a buffer, helping to maintain the blood’s pH within a narrow range. The exact mix is chosen by the dialysis team and monitored by the dialysis machine.

In peritoneal dialysis, dialysate is infused into the peritoneal cavity and remains there for a dwell time. The solution is usually rich in dextrose (glucose) to provide osmotic pressure that draws water and wastes from the blood across the peritoneal membrane. Glucose concentrations commonly correspond to 1.5%, 2.5%, or 4.25%, with alternative solutions using other osmotically active agents such as icodextrin or amino acids. Buffers in PD solutions may be bicarbonate- or lactate-based to maintain pH balance.

Safety and quality control are essential in dialysate production. The fluid must be produced under sterile, endotoxin-free conditions from purified water and concentrates, and it is typically packaged for single use or carefully reprocessed according to protocol. Proper dosing and monitoring are critical to prevent electrolyte disturbances and infection.