AMINO-ACID LOSSES AND HEMODIALYSIS MEMBRA NES

The losses of free amino acids during hemodialysis and its possible ef fects in the nutritional status have been investigated. In five patien ts on maintenance hemodialysis, the losses of free amino acids, essent ial (EAA), non-essential (NEAA) and total (TAA), were measured during 36 hemodialysis sessions using three different membranes: cuprophan, p olysulphone and polyacrylonitrile (AN-69). Every patient was dialyzed at least once with each membrane, and 12 hemodialysis sessions were pe rformed with every membrane. The hemodialysis schedule was similar in all procedures: mid-week dialysis, 3 hours, hollow fiber dialyzer, 1 m 2 of surface, blood flow of 300 ml/min and dialysate flow of 500 ml/mi n. The losses of total EAA were 820 +/- 366 mg/session for cuprophan, 1,014 +/- 381 mg/session for polysulphone and 1,821 +/- 869 mg/session for AN-69 (p < 0.01 vs cuprophan and polysulphone). The losses of tot al NEAA were 2,969 +/- 1,112 mg/session for cuprophan, 2,843 +/- 1,051 mg/session for polysulphone and 4,321 +/- 1,628 mg/session for AN-69 (p < 0.05 vs cuprophan and polysulphone). The losses of TAA were 3789 +/- 1385 mg/session for cuprophan, 3,858 +/- 1,345 mg/session for poly sulphone, and 61,42 +/- 2,308 mg/session for AN-69 (p < 0,01 and p < 0 ,05). The effects of the increased losses of amino acids on nutritiona l status were investigated in five patients on hemodialysis with AN-69 for more than six months. Anthropometric parameters (body weight, tri ceps skinfold thickness, and arm muscle circumference) and biochemical parameters (serum total protein, serum albumin, serum transferrin and plasma amino acids) were not different from those of eight patients w ith similar characteristics on hemodialysis with cuprophan. In conclus ion, although dialysis with AN-69 membrane increases the amino acid lo sses, a detrimental effect on nutritional status has not been observed .