What is dialysate?
Dialysate is a physiologic solution that consists of both inorganic ions found in the body and glucose.
The dialysate concentration of sodium and chloride is usually physiologic, whereas the concentration of magnesium and phosphorus is usually less than physiologic to allow for the removal of these substances on dialysis. The bicarbonate concentration is usually higher than the physiologic concentration to allow for the treatment of metabolic acidosis, which is common in patients undergoing dialysis. Typically, several different potassium and calcium concentrations are available so that the rate of removal of these ions can be varied as clinical circumstances dictate. The dialysate flows through the dialyzer in a countercurrent direction, preferably at a rate that is 1.5 times the blood flow rate to maximize diffusion. The temperature of the dialysate is usually set at just below the patient’s body temperature, as this setting will allow for vasoconstriction and thus minimize the risk of hypotension with volume removal on dialysis. The dialysate temperature can be adjusted by 1°C to 2°C to assist with volume removal.