Effects of biofiltration versus hemofiltration in the treatment of chronic uremia.

Biofiltration (BF), a new depurative hemo-diafiltration employing a high efficiency membrane (acrylonitrile and metallylsulphonate of sodium) and reinfusion of 8-9 liters of fluid was tested as an alternative method to hemofiltration (HF). Sixteen uremic patients who showed circulatory instabilities during traditional hemodialysis (HD) were treated with HF (27 liters infused in postdilution), or BF (210 min/session) for 12 months. Low and middle molecular weight metabolites weekly clearances, calcium, phosphorus and bicarbonate serum levels in BF and HF showed no significant differences: in BF the incidence of symptomatic hypotension events and orthostatic changes of mean blood pressure were lower than in HD, but a little higher than in HF. Our results show that BF achieves satisfactory depuration of low and middle molecular weight metabolites in a shorter time than HF and an improvement of autonomic nervous system abnormalities is observed.