Influence of exchange volume and dialysate flow rate on solute clearance in peritoneal dialysis.

To find the ideal dialysate flow rate and exchange volume for use in long-term peritoneal dialysis, 10 patients were studied over a period of 1.5 yr. Exchange volumes of 1 or 2 liters and dialysate flow rates of 1, 2, 3, 4, and 6 liters/hr were tested. Dextrose concentration remained constant at 1.5 g/100 ml. Peritoneal clearances for BUN, creatinine, and uric acid were calculated at 2, 5, 10, 15, and 20 hr during dialysis making a total of 120 clearances for each patient. All patients used a reverse osmosis automatic machine. The clearance of all three solutes tended to be higher with exchange volumes of 2 liters than they did with 1 liter; this trend was significant for BUN (P less than 0.025) and uric acid (P less than 0.025) but not for creatinine. There was a significant rise in clearance with increasing flow rates per hour for all solutes as shown in the following table. (Formula: see text), Since patients could not tolerate a flow rate of 6 liters/hr, we conclude that flow rate of 4 liters/hr with a 2-liter exchange will give maximum efficiency.