Effect of the dialysis membrane in the treatment of patients with acute renal failure.

BACKGROUND: The mortality rate among patients with acute renal failure remains high, and the role of the biocompatibility of the dialysis membrane in the resolution of this disorder is not known.

METHODS: We prospectively studied 72 patients with acute renal failure who required hemodialysis and assigned them to two treatment groups. One group underwent dialysis with the widely used cuprophane dialysis membrane, which activates the complement system and leukocytes, and the other group underwent dialysis with a synthetic polymethyl methacrylate membrane, which has a more limited effect on complement and leukocytes. Scores on the Acute Physiology, Age, and Chronic Health Evaluation (APACHE II) were calculated at the initiation of dialysis. Survival and the recovery of renal function were determined with the use of proportional-hazards and exact logistic-regression analyses.

RESULTS: When dialysis was initiated, the patients in the two groups were similar in terms of age, APACHE II scores, the prevalence of oliguria, and biochemical indexes of renal failure. Twenty-three of the 37 patients (62 percent) in the group undergoing dialysis with the polymethyl methacrylate membrane recovered renal function, as compared with 13 of the 35 patients (37 percent) in the group undergoing dialysis with the cuprophane membrane (P = 0.04 after adjustment for the APACHE II score). The median number of dialysis treatments required before the recovery of renal function was 5 in the former group and 17 in the latter group (P = 0.02). Twenty-one patients (57 percent) undergoing dialysis with the polymethyl methacrylate membrane survived, as compared with 13 patients (37 percent) undergoing dialysis with the cuprophane membrane (P = 0.11). Of the 20 patients in each group who initially had nonoliguric acute renal failure, the survival rates were 80 percent with the polymethyl methacrylate membrane and 40 percent with the cuprophane membrane (P = 0.01).

CONCLUSIONS: Among patients with acute renal failure requiring hemodialysis, the use of the polymethyl methacrylate membrane, as compared with the cuprophane membrane, resulted in improved recovery of renal function.