Clinical and technical aspects of hemofiltration

The removal of uremic substances in hemofiltration, in contrast to hemodialysis, is achieved by means of a convective transport across membranes of high porosity. Since 1974, more than 30 patients with chronic renal insufficiency have been treated with regular hemofiltration three times weekly for four to five hours each. After completing a pilot study, a controlled study to compare hemodialysis and hemofiltration was initiated during January, 1978. A normalization of blood pressure in patients with severe hypertension, and remarkable stability of the circulatory system, even after dehydration in patients who had hypotension in spite of fluid overload, could be demonstrated. Hemofiltration is preferred, especially in older patients with cardiovascular or cerebrovascular problems, because of its lower frequency of hypotensive episodes compared to dialysis. An important aim--the miniaturization of the artificial kidney--has not yet been achieved, however, because of the necessity for an extensive monitoring system for the exact proportioning of the sterile substitution fluid. First results in the application of a fluid regeneration system consising of a charcoal cartridge and a bioelectric cell, for degradation of urea, are presented.