Influence of membranes on morbidity.

Haemodialysis, a life-saving treatment extending the life of many people for up to more than 20 years, causes acute complications and symptoms and long-term uraemic complications affecting the patient's morbidity and mortality. These inadequacies have been attributed not only to the dialysate composition but also to the membrane. In evaluating the benefits of biocompatible membranes reported in the literature, we have taken into account nutritional aspects, infections, cardiovascular effects, long-term effects, the potential renoprotective effect and patients with acute renal failure survival. In spite of the wide literature on biological effects of biocompatibility of dialytic membranes, stressing the superiority of synthetic membranes, proven causal relationships between clinical diseases and biological reactions are scarce and the true impact of biological effects on the clinical state is still debatable. The results of prospective randomized controlled trials in patients with chronic renal failure are conflicting. Large trials with long follow-up times are needed to further clarify the effects of biocompatible membranes and different treatment modalities on morbidity and mortality of patients on chronic replacement therapy, but these trials are difficult because of randomization and high patient drop-out rates. However, the results of the two controlled trials on patients with acute renal failure stress the importance of biocompatible membranes. Only cost is in favour of the use of cuprophane membranes, especially in patients with acute renal failure.