Can recovered protein from the CAPD patient's own dialysis effluent substitute for dextrose?

Albumin has been evaluated as an osmotic agent for peritoneal dialysis as being physiologically safe and having modest colloidal osmotic pressure. However its extremely high cost inhibits clinical applications, and hypoalbuminemia is often seen in continuous ambulatory peritoneal dialysis (CAPD) patients, especially those with high peritoneal equilibration test (PET) values and who lose a large quantity of albumin everyday. This study aims at recovering protein from CAPD effluent and reusing it safely at reasonable cost as a substitute for dextrose. The dialysis effluent was collected and concentrated with a semipermeable membrane. Uremic toxins and low-molecular-weight solutes were removed by repeated filtration and water dilution. The concentrate was acidified with hydrochloric acid down to pH 2, thence de-acidified with water dialysis up to pH 5. At this point, the isoelectric point of albumin, at which precipitate was deposited, the precipitate was separated from the supernatant and re-dissolved into electrolyte solution. The acidified concentrate exhaled an unpleasant odor, like that of decayed food. The precipitate solution, however, did not smell at all. The initial ultrafiltration rate of the recovered protein solution was measured and compared with that of dextrose and dextran by using a high-sensitivity differential manometer, one end of which was connected with the test solution cell, and the other with the serum cell. The ends were separated by a semipermeable membrane. The recovered protein solution at 20 g/dL concentration was almost equivalent in initial ultrafiltration rate to the 2.0 g/dL dextrose solution and to 20 g/dL dextran (MW: 75,000 dalton) solution.